UNIVERSITY OF PORT HARCOURT

FOOD, NUTRITION AND TOXICOLOGY:

IS YOUR LIFE IN YOUR HANDS?

An Inaugural Lecture

By

PROFESSOR EUGENE N. ONYEIKE

B.Sc (UPH), PGDE (UNN), M.Sc, Ph.D (UPH), MNSBMB
Department of Biochemistry, Faculty of Science

INAUGURAL LECTURE SERIES

NO. 99

13TH DECEMBER, 2012

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 DEDICATION

For their foresight in sending my wife and I to school, and commitment

to seeing us through, this Inaugural Lecture is dedicated to the blessed
and evergreen memory of my late parents

Ezinna Paul Nwaogwugwu Onyeike-Nwokolekwu

Ezinne (Mrs) Sussana Onuawuchi Onyeike

and late parent in-laws

Chief Louis Ejekwurumadu Nwosu

Chief (Mrs) Annasthesia Anuchuka Nwosu.

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 ACKNOWLEDGEMENT

My gratitude goes to the Almighty God for giving me life, protection, and
for His grace to my family and I, abundant mercies and making things
possible even when they appeared impossible. I most sincerely thank the
Vice-Chancellor Professor Joseph A. Ajienka for constantly reminding me
to find time to prepare and deliver my Inaugural Lecture. I cannot thank
him enough for encouraging me, approving my request to deliver my
Inaugural Lecture and making it possible for me to deliver the lecture
today. In the Department of Biochemistry, Uniport, it is a long standing
tradition that a minimum of two Lecturers supervise the
Thesis/Dissertation of a postgraduate student and also mentor him or
her. I am grateful to Prof. Edward O. Ayalogu, (FNSBMB) (former DVC
Administration) who supervised my B.Sc and Ph.D degrees for the
support and guidance in my academic pursuits. I sincerely thank him for
always standing by me whenever I am faced with life challenges. He is a
mentor par excellence. I would like to express my gratitude to Emeritus
Prof. Emmanuel O. Anosike, (FAS) who admitted me for an M.Sc
programme in Biochemistry which he supervised. I appreciate his
contributions toward the advancement of knowledge of Biochemistry
and for inspiring me to greater heights, and also employing me as a staff
in 1991 when he was Dean, Faculty of Science; a process that was initiated
by my then Head of Department, Dr. Patrick O. Uadia (now Professor at
the University of Benin). I am grateful to Prof. P.O. Uadia for believing in
me and facilitating my employment in Uniport.
Prof. (Mrs.) Bene W. Abbey (DV-C, Research and Development)
also supervised my M.Sc and Ph.D degrees. I appreciate her
encouragement and contributions to my success story in academics. I
acknowledge with thanks the advise and efforts of Prof. (Mrs.) Stella G.
Uzogara who was one of my Ph.D Supervisors, and who, as the then
Head of Department ensured that the External Examiner finally arrived
on February 2, 1993 (after ten months) to examine my Ph.D dissertation
which was sent out in May 1992. To Prof. and Chief (Mrs.) Celestine C.
Nwachukwu, I owe a debt of thanks for their encouragement and
concern for my well being.

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 My parents Ezinna Paul N. Onyeike-Nwokolekwu and Ezinne
(Mrs.) Sussana Onuawuchi Onyeike and parent in-laws Chief Louis
Ejekwurumadu Nwosu and Chief (Mrs) Annashesia Anuchuka Nwosu of
blessed memories are remembered for sending my wife and I to school,
nurturing us to maturity, providing and caring for us while they lived,
and for instilling in us the virtues of discipline, honesty and love for
mankind. May their souls rest in peace – Amen!
I am highly indebted to my wife, friend, confidant and help mate
Dr. (Mrs.) Victoria C. Onyeike and children Chidinma, Nzubechukwu
and Nneoma for their love, patience, understanding and unflinching
support in all that I have had the opportunity of doing. I cannot thank
them enough for providing a peaceful and happy home that enables me
to excel in my ever busy schedules of life in the academia and in
community service. I wish to appreciate the assistance and co-operation
of other members of my inner household especially Miss Francisca
Oluchi Aririguzo, Miss Augusta Onyinyechi Ufomadu and Miss Ndidi
Helen Onyeike. I thank my brothers and their families (Mr. & Mrs.
Romanus C. Onyeike; Mr. & Mrs. Vitalis A. Onyeike; Mr. & Mrs. Linus N.
Onyeike) and my sisters Joy, Sybilia, Juliet and their families (Mr. & Mrs.
Joseph N. Onuoha; Mr. & Mrs. Paul Onuoha and Mr. & Mrs. Christopher
Etim) for their prayers and contributions to my success in life. My niece
Rosana and her husband (Mr & Mrs Ndulaka Anyanwu) are appreciated
for their love and concern.
Barr. Lucius E. Nwosu Esq is a distinguished Senior Advocate of
Nigeria (SAN) with a human face having imparted positively to the lives
of many people. I thank him for his useful advise to me in taking certain
important decisions. My deep appreciation therefore goes to him and his
amiable wife Dr. Mrs. Chinelo Nwosu for their encouragement, love,
moral and financial support. I cannot thank them enough. For their
invaluable and wonderful assistance and concern, I thank Mrs. Celestina
Nwosu and Mr. & Mrs. Darlington C. Nnodi.
I am thankful to Prof. C.M. Ojinnaka, (FCSN) for his
encouragement in my academic pursuits and facilitating the Prima Facie
case for my Professorship. For his academic and professional advise and
support, I thank Prof. B.E. Okoli who was Dean when the Faculty of

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Science approved the Prima Facie case for my Readership. I am grateful
to Prof. & Mrs. C.T. Maduka for their encouragement at all times.
I am grateful to Prof. L.C. Amajor for advising me to complement
teaching with research and publications to enable me grow as an
academic. Having shared office with Professor Augustine A. Uwakwe
from 1991-2012 (21 years), it is understandable why he was appointed
University Orator to introduce me during this Inaugural Lecture. I
remain grateful to him for his love, understanding, cordial relationship
with me, useful discussions and academic interactions, and for accepting
to be Orator in today’s Inaugural Lecture. I am grateful to the Chairman
(Prof. Anthonia A. Okerengwo), and members of Academic Staff Union
of Universities (ASUU), Uniport Branch and ASUU National Executive
Council (NEC) for the struggles to improve the quality of education and
life of University Lecturers in Nigeria.
I thank my Traditional Ruler and Royal Father of today HRH Eze
Boniface N. Amaechi (Ogbodudu II of Mbaukwu Ihitte Autonomous
Community, Ezinihitte Mbaise) for his encouragement, support and
constantly identifying with my progress in life, and finding time to come
to Port Harcourt to grace this occassion.
My secondary school teachers at Ezzikwo High School, Abakaliki
(1972-1976) are highly appreciated especially, Mr. Cletus Eze (A.K.A. Eze
Junior) for stimulating my interest in Science especially Chemistry and
also Mathematics.
My current Head of Department Dr. (Mrs.) Eka B. Essien and the
Dean, Faculty of Science, Prof. (Mrs.) Nnenna Frank-Peterside are
appreciated for their support. I thank all my other academic colleagues,
technical and administrative staff in the Biochemistry Family, Uniport for
their understanding, co-operation and contributions to my career
especially Prof. Mike O. Monanu, Prof. (Mrs.) Joyce O. Akaninwor, Prof.
Comfort O. Monago, Prof. Matthew O. Wegwu, Dr. Eucharia O. Nwaichi,
Dr. Kingsley C. Patrick-Iwuanyanwu, Dr. (Mrs.) Catherine C. Ikewuchi,
Dr. Jude C. Ikewuchi, Dr. Francis C. Onwuka, Dr. Samuel Onuoha, Dr.
Lawrence C. Chuku, Dr. Donatus C. Beleonwu, Dr. (Mrs.) Mercy
Ifeanacho, Dr. (Mrs.) Blessing M. Onyegeme-Okerenta, Mr. Mark-Balm
Telema, Mr. Sam Idiasirue, Mr. Felix C. Ezenatein, Mr. Richard Ohiri, Mr.
Steve I. Omeodu, Dr. Emmanuel N. Agomuo and Dr. Benjamin A. Amadi.

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 I thank the Chaplain, Chapel of the Annunciation, Catholic
Chaplaincy, Uniport Rev. Fr. Joseph Kabari, the Assistant Chaplains
Msgr. Prof. Sylvanus I. Udoidem and Rev. Fr. John C. Nebo; the Resident
Associates Rev. Fr. Professors Chris I. Ejizu, Boniface E. Nwigwe and
Vincent G. Nyoyoko; then Rev. Fathers Anthony N. Nwudah, Jerome
Ogada Nwachukwu, Silas Onuoha, Leo Ekechukwu, Christian Echewodo,
Patrick Mbazuigwe, Innocent Uwah, Dr. K. K. Obasi, Sr. Onyegbule, Sr.
Felicia Ekpenyong and members of the Uniport Chaplaincy and St. Rose’s
Catholic Church Ihitte, Ezinihitte Mbaise for their prayers and
contribution to my spiritual growth.
I wish to express my sincere appreciation to the Director of
Academic Affairs, Uniport, Mrs. Dorcas D. Otto and Mr. G.C. Okezie for
encouraging me not to despair in the quest to deliver my Inaugural
Lecture in the face of other life challenges. I appreciate the support from
Prof. & Mrs. Eunice O. Nwachukwu and family, Prof. & Mrs. Enoch O.
Nwachukwu Mr. Roland Wabali (Director, Establishments)and Mr. &
Mrs. John Paul Enebeli.
I wish to acknowledge all the authors whose works are cited in
this lecture, including my past and present supervisees. The technical
assistance of Dr. and Dr. (Mrs.) Jude C. Ikewuchi and Dr. Eucharia O.
Nwaichi in the course of my preparation of the lecture manuscript is
highly appreciated. I appreciate the effort of Mr. Kenneth Onyenkwere in
typing the manuscript of this lecture.
For their encouragement and support, I remain grateful to Prof.
and Prof. (Mrs.) Ethelbert C. Nduka (DVC Administration) Uniport, Prof
& Barr. (Mrs.) A.I. Joe, (DVC Academic), Mrs. Matilda Nnodim
(Registrar) Uniport, Mr. Vitalis Aliezi (Bursar), Dr. (Mrs.) Cordelia O.
Nwodo (University Librarian), Mr. Williams Wodi (University PRO),
Chief & Mrs. Callistus A. Imo and Mr & Mrs. Vitalis C. Ugbaja.
For their friendship, love and prayers for the well-being of my
family and I, the following persons are appreciated Prof. & Dr. (Mrs.)
Nnaemeka F. Ukaigwe, Dr. & Dr. (Mrs.) Leo Osuji, Prof. & Mrs. Lawrence
U.S. Ezeanyika, Prince and Mrs. Malachy K.O. Mbazuigwe, Mr. & Mrs.
Eugene O. Odom, Mr. & Mrs. Desmond U. Alozie, Mr. & Mrs.
Christopher C. Iwuchukwu, Mr. & Mrs. Joachin U. Odom, Mr. & Mrs.
Innocent O. Nwaogwugwu, Mr. & Mrs. Donatus Oguh, Mr. & Mrs.

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Richard Nwudah, Mr. & Mrs. Echeme Ukpong Ukpai, Mr. & Dr. (Mrs.)
Innocent O. Onyido, Engr. and Dr. (Mrs.) Goddy Asodike, Prof. and Mrs
Cyriacus C. Ekennia, Prof. and Dr. (Mrs.) O.C. Umeozor, Prof. and Mrs.
Augunus N. Uhegbu, Prof. & Mrs. Emmanuel I. Akubugwo, Prof. & Mrs.
Emma C. Emasealu, Prof. & Mrs. Dennis P. Ekpo, Prof. & Dr. (Mrs) Obi
U. Njoku, Mr. & Mrs. Brendan C. Imoh, Mr. & Mrs. Damian Ugbaja, Dr. &
Mrs. Success A.C. Anyanwu, Mr. & Mrs. Gabriel Awuja, Mr. & Mrs.
Anthony Njoku, Dr. & Mrs. Matthew N. Adindu, Sir & Lady Livinus
Njoku, Engr. & Ezinne Sylvester C. Nwachukwu, Dr. & Mrs. Protus O.
Kemdirim, Mr. & Mrs. Chukwuma Ebere, Mr. & Mrs. Paschal Ibeh and all
members of Mbaise Senior Staff Association, Uniport.
For their love, friendship and support, I appreciate Prof. & Mrs.
Ferdinand C. Chilaka, Arc. Sir & Lady Zaccheus O. Ijeoma, Dr. & Mrs.
Hilary N. Ezeh, Mr. & Mrs. Michael A. Uzor, Ven. Prof. & Mrs.
Wellington O. Wotogbe-Weneka, Prof. & Mrs. Frank A.O. Ugiomoh,
Prof. & Mrs. Paul Eke, Prof. & Mrs. Victor U. Ukaegbu, Prof. & Dr. (Mrs)
Martins I. Ifeanacho, Dr. & Dr. (Mrs) Greg O. Agabi, Engr. & Mrs. Felix
Uhegbu, Engr. & Mrs. Patrick I. Imoh, Mr. & Mrs. Livinus Uhegbu, Engr.
& Mrs. Chris Iwu, Mr. & Mrs. Theophilus Umunakwe, Dr. & Dr. (Mrs.)
Augustine O. C. Imo, Dr. & Dr. (Mrs.)Obioma N. U. Ekennia, Dr. & Dr.
(Mrs.) Francis Amaechi, Prof. A. E. Arinze, Prof. & Mrs. Anthony E.
Ataga, Mr. & Mrs. Raymond Anyanwu, Prof. & Dr. (Mrs.) Donatus I.
Anyanwu, Dr. & Mrs. Clement C. Iro, Barr. & Mrs. Pat Ekeanyanwu, Chief
Sir Paul A. Iwunna, Engr & Prof. (Mrs.) B.N. Obasi, Prof. & Dr. (Mrs.)
Chinedu C. Chukueggu, Dr. & Mrs. G.B. Eke and Prof. & Mrs. I.L.
Nwaogazie.
For their encouragement over the years, I thank Dr. (Mrs.) Irene
I. Ijeh, Prof. & Dr. (Mrs.) C.S. Nwodo, Chief (Mrs.) Bridget I. Nzimiro, Dr.
& Mrs. Etiido Inyang, Prof. & Prof. (Mrs.) Ndu Eke, Prof. & Mrs. P.C.
Stanley, Prof. & Prof. (Mrs.) O.A. Ejele, Prof. (Mrs.) Roseline S. Konya
(JP), Prof. Edith N. Elenwo, Prof. & Dr. (Mrs.) Mark Anikpo, Prof. & Dr.
(Mrs.) Benjamin A. Eheazu, Prof. & Mrs. Onyewuchi Akaranta, Prof. &
Dr. (Mrs.) A.K. Okorosaye-Orubite, Mr. & Mrs. Alex E. Onuoha, Mr. &
Mrs. Ferdinand Opara, Mr. & Mrs. Charles Onwuanuogu, Chief & Mrs.
Peter Chikere, Mr. & Mrs. Luke Ajero, Mr. & Mrs. Ezumah Igwiloh and
Mr. & Mrs. Okezie O. Ochuba. I wish to thank the following persons for

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their encouragement, Prof. & Mrs. Peter O.M. Nnabuo, Dr. & Mrs. S.O.
Oluwuo, Prof. & Mrs. Nich C. Oforka, Prof. & Mrs. Julian O. Osuji, Mr. &
Mrs. Cajetan J. Ihejirika, Prof. & Mrs. B.J.O. Efiuvwevwere, Prof. & Mrs.
Blessing C. Didia and Mr. Iyke Oke.
I am sincerely grateful to the following for their immense
support, kindness and encouragement to my family and I, Prof. & Mrs.
Don M. Baridam (Immediate Past Vice-Chancellor, Uniport), Prof. & Dr.
(Mrs.) John O.E. Otaigbe, Prof. & Mrs. Samuel N. Okiwelu, Sir & Dr.
(Mrs.) Jude E. Onuoha and Sir & Dr. (Mrs.) Michael N.A. Eke. I
remember and appreciate the following for their encouragement, Mr. &
Mrs. Pius Ugochukwu, Mr. & Mrs. Vitalis Onyemachi, Prof. & Mrs.
Francis D. Sikoki, Prof. & Mrs. Joseph O. Ebeniro, Prof. & Mrs. O.E.
Abumere and Prof. & Mrs. John T. Agberia.
Indeed, the list is inexhaustible. I therefore remain indebted to
many of my colleagues, friends, relations, well-wishers and students who
have imparted positively to my life, and whose names could not be
mentioned here for constraint of time and space. I remember and love all
of you.
Finally, I thank every member of Uniport Community and those
from outside the University who found time to attend this Inaugural
Lecture. May God bless and keep all of you in Jesus name – Amen!

Professor E.N. Onyeike.

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 TABLE OF CONTENT

Preliminaries ………………………………………………………………… i
Introduction …………………………………………………………………. 1
Rationale for the choice of lecture topic……………………………………. 4
The subject matter of Biochemistry…………………………………………. 4
Brief History of Biochemistry………………………………………………… 5
Food and its classification……………………………………………………. 7
Food science and its sub-disciplines…………………………………………. 8
Food processing and its merits and demerits ………………………………. 12
Effect of processing on nutrient composition and toxicants in foods…… 16
Food preservation: Physical and chemical methods ……………………….. 20
Reasons for which foods are preserved and commonly used
preservatives... 24
Nutrition, nutrients in foods, sources and functions……………………….. 31
Essential nutrients…………………………………………………………... 35
Nutritional Disorders: Aetiology, Features, Prevention and Food
sources of deficient nutrients that should be consumed ………………….. 37
Malnutrition, undernourishment, over-nourishment, balanced and
unbalanced diet, Clinical Nutrition………………………………………… 55
Nutritional disorders due to mineral deficiency and clinical
malnutrition…58
Toxicology and branches……………………………………………………. 60
Some terminologies used in toxicology……………………………………... 62
Toxicants in natural association with foods………………………………... 65
Environmental toxicants and contaminants in foods and health effects…..
72
Other environmental food contaminants…………………………………... 76
Carcinogenesis and its Mechanism………………………………………… 77
Contamination of foods by microbes………………………………………. 78
Toxicants produced during heat treatment of foods………………………. 78
Summary of my research publications and contributions to knowledge…..
81
Recommendations …………………………………………………………. 101
Concluding Remarks ………………………………………………………. 102

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References …………………………………………………………………. 105
Citation on the Inaugural Lecturer………………………………………... 120

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Introduction
In one of the seven second-generation Universities in Nigeria in which 98
Professors had delivered their Inaugural Lectures and more than 150
others are awaiting for the opportunity to perform this academic and
intellectual ritual, I consider myself privileged to have been granted the
th
request to deliver the 99 Inaugural Lecture of this Unique and
Entrepreneurial University.

An Inaugural Lecture is one delivered by a University Professor

in which the Professor is expected to make public pronouncements on
his/her contributions to knowledge through research findings and new
ideas in the area of specialization before a multi-disciplinary audience. It
affords the Lecturer the opportunity to share with the public his
academic achievements, and the area he wishes to make impact in the
future. Realizing that an Inaugural Lecture may not be delivered more
than once in a period of academic career, the Inaugural Lecturer tries to
show what he professes, and the extent to which his work over many
years have imparted positively on the lives of people in the society.
Vice-Chancellor Sir, in preparing and delivering this lecture, the
greatest challenge which I have faced, is how to simplify the language
and depth of instruction to the level that may make sense to, and
facilitate comprehension by non-experts without compromising quality
and standard. For instance, how do I, as a Nutritional Biochemist and
Toxicologist explain to non-experts in Biochemistry that the reaction of
an enzyme trypsin (a biological catalyst) with a synthetic substrate α-N-
benzoyl-DL-arginine-paranitroanilide hydrochloride (BAPNA) would
produce para nitroaniline, which absorbance is measured
spectrophotometrically at 410nm as a function of trypsin inhibitor
activity in the widely consumed African yam bean seeds (Sphenostylis
stenocarpa)? It is also a challenge to reduce the volume of information
emanating from my many years of teaching, research, publications and
community service which form the basis for my new ideas for the sole
aim of not making this scientific discourse boring to the distinguished
audience here present. I will try the best I can to explain in simple and

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understandable terms, the concepts associated with the lecture topic,
and I invite you to please relax and listen to the lecture.

When Should a Professor Deliver an Inaugural Lecture?

There appears to be divergent views on when a Professor should deliver
an Inaugural Lecture. According to Akinpelu (1987) as reported by
Eheazu (1998), Inaugural Lectures should be made to assume their true
essence of introducing new Professors to mark a fresh beginning of a
deeply and mature scholarship and productivity rather than a
termination of same. Four months after he was appointed to the Chair of
Regius Professor of Modern History in February 1895 by the University of
Cambridge, the new Professor Lord Acton delivered his Inaugural
Lecture (Figgis and Laurence, 1960). In Nigeria, it may take some
Professors between two and ten years before they can deliver their
Inaugural Lectures.

Vice-Chancellors Sir, it may be that

(i) Some Professors do not show interest because of absence of cash
price award for preparing and delivering such a lecture.
(ii) A number of Professors may feel that they do not need to deliver
an Inaugural Lecture for promotion having attained the status of
“Academic Generals”.
(iii) There is the uncertainty of a candidate being promoted to the
rank of Professor by the University especially when a particular
Vice-Chancellor is on seat. It is today common knowledge that
the Vice-Chancellor sends out a candidate’s publications for
external assessment for Professorship after the candidate has
scaled through the internal assessments at the Department,
Faculty and Central University Appointments and Promotions
Committee (Academic). The Vice-Chancellor alone also knows
when the external assessment reports have been received and
whether they are positive or negative. If there is the unfortunate
problem of abuse of position, it may affect a candidate for
promotion who is listed either for reasons known or unknown to
him in the Vice-Chancellor’s black book, as it did happen in 2008
and 2009 in one of the Universities in the South-South
geopolitical zone of Nigeria (not Uniport). This uncertainty

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 affects one’s desire to start early enough to prepare a lecture
he/she is not sure to deliver.

(iv) Some Professors may be too busy with research activities,

academic and administrative work, politics as well as other
engagements within and outside the University that they do not
find time to prepare and deliver an Inaugural Lecture.

In the analysis of Uniport Professors and Inaugural Lectures, and

defining the time interval between becoming a Professor and delivering
Inaugural Lecture as the waiting time, Nduka (2007) reported an average
waiting time before Inaugural Lectures of 8, 4, 3, 5, 6 and 6 years for
Professors in the Faculties of Education, Engineering, Health Sciences,
Humanities, Science and Social Sciences respectively. My five years and
nine months (approximately 6 years) waiting time as Professor before
this Inaugural Lecture is consistent with the report of Nduka (2007) for
the average waiting time of 6years before Inaugural Lectures for
Professors in the Faculty of Science.

Rationale for the Choice of the Lecture Topic

Hardly would you find a Professor of Computer Science delivering an
Inaugural Lecture in Religious and Cultural Studies which is not his area
of specialization. The topic of this lecture is indeed a logical outcome of
my teaching, research and publications from 1991 to date, for which I was
th
elevated to the rank of Professor of Biochemistry with effect from 19
March, 2007.
Vice-Chancellor Sir, I have for many years of my research in
Biochemistry been associated with foods, their nutrient composition and
the toxicants that occur in natural and synthetic association with such
food materials. Due to the current global food crisis, part of our challenge
today in Nutritional Biochemistry and Toxicology is how to ensure
adequate food production and supply, food processing, food
security/safety, consumption and utilization for appropriate nutrients
needed for healthy living. As the food we eat contain nutrients and
toxicants, there is therefore food in health and in disease. In a hunger-
prone Nigerian society where many households are managing but
pretend that all is well, people tend to eat anything they see as food.

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 The dilemma faced by Nigerian food consumers and the need for
information-knowledge-awareness on foods informed my choice of the
topic for this lecture thus “Food, Nutrition and Toxicology: Is Your Life in
Your Hands?”

The Subject Matter of Biochemistry

Biochemistry is a discipline that deals with the application of Chemistry
to the study of biological processes at the cellular and molecular level. It
is derived from the Greek word Bioxnueia biochemeia, which means “the
chemistry of life”. It studies the structures and functions of cellular
components (carbohydrates, lipids, proteins and nucleic acids).
Biochemistry explores the chemistry of living systems, and the molecular
basis for the changes that take place in living cells, and it is hence both a
life science and a chemical science. Biochemistry is not a combination of
Biology and Chemistry, but a discipline that applies the methods of
Chemistry, Biology, Mathematics, Physics, Microbiology, Immunology,
Thermodynamics and Genetics to study the structure and behaviour of
the complex molecules found in biological systems and the manner in
which these molecules interact to form biological cells, tissues and whole
organisms. This subject has become the foundation for understanding all
biological reactions, and has provided explanations for the aetiology of
many diseases in animals, plants and microbes. It also frequently
suggests the ways by which such diseases may be treated or cured, and
can therefore be regarded as an “essential science”.
Biochemistry is also considered as a practical science since it
unravels the complex chemical reactions in many living systems and
provides the basis for practical advances in Agriculture, Biotechnology,
Molecular Genetics, Genetic Engineering and Medicine.

Brief History of Biochemistry

Compared to other sciences, Biochemistry is a relatively young discipline
th
which emerged about the 19 Century when scientists used Chemistry,
Physiology and Biology to study the Chemistry of living organisms.
Lomonosov (1748) was the Russian who discovered the Law of
Conservation of Matter and its applicability to both living and non-living
things. Hitherto, it was believed that only living things could produce the
molecules of life from already existing biological molecules. The

4
discovery of oxygen
needed for respiration in plants and animals by Scheel and Priestly, led
to the discovery of the process by which plants manufacture
food (photosynthesis) from water and carbon(IV)oxide
6CO2  6H 2O chlorophyll, light C6 H12O6  6O2 .


Between 1748 and 1828, many organic molecules such as urea,

acids, alcohols, fatty acids and amino acids were isolated from living
things. To establish for instance that organic compounds can be made
artificially, the German Chemist Friedrich Wohler published a paper on
the laboratory synthesis of urea (Wohler, 1828), a major product of
nitrogen metabolism in many living systems including man. The
synthesis of urea was an accomplishment of great importance, and the
year 1828 was regarded as a turning point in the establishment of
Biochemistry as a science (Ekeke, 2000). The dawn of Biochemistry may
have been

(i) the discovery of the first enzyme amylase or diastase by Anselme

Paven in 1833
(ii) the discovery of DNA (the genetic material of most plants and
animals) by the Swiss Biochemist, Miescher in 1869)
(iii) the first demonstration of a complex biochemical process outside
the cell (alcoholic fermentation in cell extracts of yeast) by
Eduard Buchner in 1896.

Although the history of Biochemistry spans nearly 405 years, the term
“biochemistry” which was formerly referred to as or called Physiological
Chemistry was first used in 1882 while the formal coinage was by a
German Chemist Carl Neuberg in 1903.

Among the major landmarks in Biochemistry since 1903 were

(i) The establishment of the secondary structure of
deoxyribonucleic acid or DNA (the molecule that carries
heredity) by the British Biochemists, Watson and Crick in 1953.
(ii) The ability of yeast extracts to ferment sucrose in the absence of
living yeast cells was studied by Eduard Buchner as from 1897 at

5
 the University of Berlin. He found that sucrose was fermented
even without living yeast cells in the extract mixture and named
the enzyme that caused the fermentation zymase, for which he
was awarded a Nobel Prize in Chemistry in 1907 for his
biochemical research and discovery of cell-free fermentation.
(iii) In 1926, James B. Summer crystallized urease as a pure protein
and also catalase in 1937. The conclusion that pure proteins can
be enzymes was demonstrated by Northrop and Stanley (1930)
who worked on the digestive enzymes pepsin, trypsin and
chymotrypsin. The three scientists (Summer, Northrop and
Stanley) were awarded the 1946 Nobel Prize in Chemistry. One
can at this point see the basis for the strong relationship that
exists between Chemistry and Biochemistry, and why the
founding fathers of this University established the former School
of Chemical Sciences that comprised the disciplines – Pure
Chemistry, Biochemistry and Applied Chemistry, and which
lasted from 1977 to the end of 1982.
(iv) The first controlled experiments in human metabolism was
published by Santorio Sanctorius in 1614 in his book Ars de
Statica Medecina in which he described how he weighed himself
before and after eating, sleeping, working, sex, fasting, drinking
and excreting and found that most of the food he took in was
lost through what he referred to as “insensible perspiration”.

Since 1903, Biochemistry has till date, advanced with the development of
new techniques which have facilitated the discovery and analysis of
biomolecules and metabolic pathways of the cellular systems. It is
therefore evident that like other sciences, Biochemistry is rapidly
evolving, and the future of this discipline will continue to be assured so
long as life on earth persists.

Vice-Chancellor Sir, the findings in Biochemistry are today

applied in many disciplines from Genetics to Molecular Biology and from
Agriculture to Medicine and Industry.

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Branches of Biochemistry
Among the basic sciences, Biochemistry is one of the broadest disciplines
and is therefore a varied science. The sub-specialities of Biochemistry
include Enzymology, Nutritional Biochemistry and Toxicology, Medical
and Clinical Biochemistry, Environmental Biochemistry, Pharmacological
Biochemistry, Industrial Biochemistry, Food Science and Technology,
Neurochemistry, Physical Biochemistry, Immunochemistry, Molecular
Genetics, Genetic Engineering, and Bioinformatics.
Vice-Chancellor Sir, having studied the various areas of
Biochemistry, I decided to narrow down to Nutritional Biochemistry and
Toxicology where most of my contributions in teaching, research and
publications are domiciled.

Food
In the olden days, food was simply considered as anything people ate or
took in, in response to hunger or illness. When one got up from sleep, he
ate, and when he travelled from one place to another, he simply ate. No
one really understood what was good or bad to eat. The Physicians then
attempted to prescribe diets as remedies for illness, but the process was
more of astrology than medicine (Mckenny, 2009).
The tenet “let food be thy medicine and medicine be thy food”
was exposed by Hippocrates about 2500 years ago, to predict the
relationship between foods for health and their therapeutic uses (Hasler,
1998 a,b; Bagchi, 2006; Ikewuchi, 2012)
Today, food can be defined as any edible substance that is of
plant, animal or microbial origin, which is a source of nutrients and
which when consumed, absorbed and oxidized (broken down) provides
energy which the body uses to do all forms of biological work, maintain
and repair damaged tissues, enhance growth and development, aid
mental development and proper functioning of the brain as well as giving
well being or nourishment to the food consumer.
When we say that an animal food such as meat contains protein,
it simply means that it contains the nutrient protein in the highest
amount relative to other nutrients (carbohydrate, fats, ash, vitamins,
minerals and water). Hence, a plant food such as yam contains other
nutrients but with the highest carbohydrate content.

7
Classification of Foods According to Nutrient Levels
i. Proteinous Foods: These contain mainly protein in relation to
other nutrients. Examples are meat from poultry (chicken), pig
(pork), cow (beef), sheep (mutton). There are snake, rabbit,
weevil, grasshopper, dog and goat meat. Other proteinous foods
are egg, milk, microbes (processed yeast powder and edible
cultured microbes such as single cell protein), fishes, legume
seeds (soy bean, cow pea, lima bean etc).
ii. Energy-giving Foods: They contain more of proteins,
carbohydrates and fats/oils. Carbohydrate foods include yams,
cassava, sweet potato, cereals (maize, rice, and millet) while fat-
containing foods include oil seeds (coconut, groundnut, melon,
dikanut), red palm oil etc. Proteinous foods are also energy-
giving foods.
iii. Vitamin and mineral foods: They are required in minute
amounts for the proper functioning of the body. They include
fruits (oranges, pineapples, bananas etc), edible leafy vegetables
(pumpkin leaf, bitter leaf, hard leaf, water leaf etc). Apart from
providing vitamins A, D, E, K, B and C and the minerals Mg, Na,
Fe, Zn, Cu, etc, they are good sources of fibre (roughages) which
aid digestion of food and the removal of bulk stool from the
alimentary canal, thereby preventing cancer of the colon.

Classification of Foods According to Sources

i. Plant Sources: they include
(a) Cereal grains (rye, oat, maize, rice, sorghum) which can be
processed into flours, biscuits, beer, bread, beverages etc.
(b) Roots and stem tubers such as yams, carrots, cassava,
potatoes
(c) Fruits (apples, oranges, bananas, paw-paw, mangoes, pear
etc)
(d) Vegetables of all kinds (water leaf, spinach, tomatoes, hard
leaf, green, okra, fluted pumpkin etc)
(e) Legumes (Cowpea, African yam bean, Bambara groundnut
and Soyabean.

8
 (f) Nuts (Coconut, Pea, Palm, Walnut etc).
ii. Animal Sources – meat, egg, fish, milk etc.
iii. Microbial Sources: Example is single cell protein (SCP) obtained
from edible cultured micro organisms (bacteria, mould, yeast). It
is used mainly as animal feed to improve carcass quality, animal
growth and for better meat.

Single cell protein is not directly consumed by most humans despite its
high protein due to the problem of production and acceptability. By
enhancing animal production, SCP is indirectly beneficial to human
nutrition. There are also mushrooms which are cultivated, harvested and
processed into foods or used in preparing soup and stew.

Food Science
Food science deals with the scientific and technological aspects of foods
and related products beginning with harvesting (slaughtering) and
ending with cooking and consumption. It is concerned with the study of
the composition and properties of food. In the October 2006 issue of
Food Technology, the 2006/2007 President of the Institute of Food
Technology (IFT) Dennis R. Heldman noted that the IFT Committee on
Higher Education currently defined food science as a discipline in which
the engineering, biological and physical sciences are used to study the
nature of foods, the causes of deterioration, the principles underlying
food processing, and the improvement of foods for the consuming public
(Heldman, 2006; Wanucha, 2009). Food science is a highly
interdisciplinary applied science that embodies concepts from fields of
chemistry, biochemistry, nutrition, microbiology and chemical
engineering which are studied to provide nutritious, safe and wholesome
food supply to food consumers. Two major options in food science are
(i) Food Science and Technology
(ii) Food Health and the Environment.
Food scientists are involved in the development of new food products,
design of processes to produce these foods, choice of packaging
materials, shelf-life studies, sensory evaluation of the products with
trained expert panels or potential consumers as well as microbiological
and chemical testing (Food Science-Wikipedia)

9
 The food scientist is concerned with the determination of the
biological, chemical and physical nature of food in terms of composition,
quality, safety and consumption with the application of science and
engineering to the processing, preservation, storage and use of food and
its related products.
Subdisciplines of Food Science
Some of the subdisciplines of food science (Wikipedia, 2009) include
(i) Food Safety: This is concerned with the causes, prevention and
communication dealing with food-borne illness. It also tells us
about methods of ensuring that foods may not lead to harmful
effects when consumed.
(ii) Food Microbiology: It is concerned with the positive and
negative interactions between microorganisms and foods
(iii) Food Preservation: This deals with the causes and prevention
of quality degradation in food samples.
(iv) Food Engineering: It is concerned with the industrial processes
used to manufacture food.
(v) Product Development: Here, we learn about the invention of
new food products from existing food materials.
(vi) Sensory analysis/evaluation: This is the study of how food is
perceived by the consumers’ senses in terms of the organoleptic
properties such as colour, texture, taste, aroma, consistency and
overall acceptability.
(vii) Food Chemistry: This deals with the molecular composition of
food and the involvement of these molecules in chemical
reactions. It also gives information about the quality,
concentration and value of nutrients in foods.
(viii) Food packaging: This is the study of how packaging is used to
preserve food after it has been processed.
(ix) Molecular gastronomy: This is the scientific investigation of
processes in cooking, social and artistic gastronomical
phenomena
(x) Food Technology: This deals with the technological aspects of
food
(xi) Food Physics: This deals with the physical aspects of foods such
as viscosity, creaminess and texture.

10
Among the subdisciplines of food science, food technology assumes
prominence that we now talk more of the Department of Food Science
and Technology. Food technology is the application of food science to
the selection, preservation, processing, packaging, distribution and use of
safe, nutritious and wholesome food. Food Scientists and Technologists
study biological, chemical and physical composition of foods and develop
ways to process, preserve, package or store foods to meet government
and industry specifications and regulations.
Early history of food technology dates back to 1810 when
Nicholas Appert developed the canning process which has had a major
impact on food preservation techniques, without knowing the principle
on which the process worked. Louis Pasteur’s (1864) researches on the
spoilage of wine, production of alcohol, vinegar, beer and the souring of
milk were early attempts to put food technology on a scientific basis.
Pasteur developed the process of heating milk and milk products to
destroy food-spoilage and disease-producing micorganisms
(pasteurization), and in his research into food technology, he became the
pioneer in bacteriology and of modern preventive medicine. Among the
landmarks in food technology are
 The development of instant milk powder (instantized milk
powder) which has become the basis of a variety of new products
for which D.D Peebles received a Patent (U.S Patent 2,835,586).
These new products are rehydratable in cold water or milk- a
process that increases the surface area of the powdered product
by partial rehydration of spray-dried milk powder.
 The development of continuous freeze-drying of coffee.
 Decaffeination of coffee and tea which was first developed on a
commercial basis in Europe around 1900 and described in U.S.
Patent 897, 763. Green coffee beans are treated with steam or
water around 20% moisture. The added water and heat separate
caffeine (an alkaloid) from the bean to its surface. Solvents are
then used to remove the caffeine from the beans.
 Food technology now allows production of foods to be more
efficient i.e. there is process optimization. Methods of food
production are now more sophisticated.
Presently, food technology is considered under

11
(i) Commercial Products- These include vegetable oil, margarine,
beer, baked products, marshed yams and alcoholic beverages.
These are produced in the industries for commercial purposes.
(ii) Removal of harmful ingredients and toxicants to make the food
fit for consumption.
(iii) Food stability in which meals are made more palatable and
presentable by the addition of emulsifiers and food stabilizers
during food processing. When food containers (cans, bottles,
polyethylene bags) are opened for a long time, there is microbial
deterioration and spoilage. For example, oil becomes rancid, beer
develops haze (polyphenolic compounds) and milk becomes
sour.
(iv) Supplementation with ingredients such as vitamins and protein
which are added to enrich the food. Spices are added to enhance
flavour
(v) Production of new foods such as semovita, cocoa butter,
semolina and soy-ogi which in Nigeria are products of the
Federal Institute of Industrial Research at Oshodi, Lagos.

Through food technology, food is produced faster and in a commercial

quantity at low cost. It saves labour but results in unemployment.

Food Processing
Food processing covers a field of study from simple cooking, drying and
heating to the use of irradiation. It is the set of methods and techniques
employed in the transformation of raw food materials into commercially
sterile food products of highly extended shelf-life and stability. Food
processing is also the act of converting foods into forms that can enhance
their utilization or consumption by humans or animals either in the
home or by the food processing industry. In food processing, harvested
crop plant and animal food products are used to produce attractive,
taste-appealing, marketable, long shelf-life food products.
The food processing methods often used in the homes include
(i) cooking, boiling, steaming, autoclaving, frying, roasting and
baking. These are all forms of heat treatment/processing

12
(ii) Grinding into flour as in the case of legume seeds, cereal grains
and crayfish etc.
(iii) Mashing as in barley used in the brewing industry during the
manufacture of beer.
(iv) pounding as in the production of fufu from cooked
yam/cocoyam/cassava.
(v) Sun-drying and oven-drying of foods to reduce the moisture
content and prevent microbial spoilage thereby increasing the
shelf-life and keepability (keeping quality) of such foods. High
moisture promotes deterioration and spoilage by
microorganisms.
(vi) Soaking and dehulling as in cowpea seeds used to make akara.
(vii) Canning: Canned foods such as tomatoes, beer, jollof rice, milk,
beverages (bournvita, milk, nescafe) are processed from their
various raw materials
(viii) Fermentation: This is a food processing method that effectively
removes toxicants from cereals and legumes and improves their
digestibility and sensory characteristics (Reddy and Pierson,
1994). During fermentation, enzymes produced by microbes
breakdown proteins and starches to produce amino acids and
sugars. Levels of riboflavin, niacin and methionine are increased,
vitamin B12 is synthesized and there is increase in the amount of
available iron (Ackroyd and Doughty, 1964).
Most foods especially roots and tubers are usually consumed after
processing since the latter may increase their safety, keepability,
palatability, digestibility and utilization. One’s life is in his hands if he
decides to consume foods that are not processed and the quality not
evaluated, not palatable, cannot keep for a long time without spoilage by
microbes, cannot easily be digested and utilized by the body for growth
and energy, and whose safety is not guaranteed. Yam tubers are peeled,
washed, boiled and pounded in a wooden mortar to produce a dough
called pounded yam. Yams are also eaten boiled, fried, baked or roasted
and may be processed into flour used to prepare composite flour with
cereal (wheat) used in baking. The yam flour can also be used as soup
thickener.

13
 Cassava is a good source of carbohydrate for human and
livestock. For the red species, the root may be boiled and eaten with oil.
The roots may be peeled, sliced, sun-dried, ground into flour and used to
prepare various local diets. To process into garri, the roots are peeled,
washed, grated, fermented and fried into white garri flour. Red garri is
produced by the addition of red palm oil prior to frying. I recommend
red garri to the white one because red garri contains little or no cyanide
and the latter is detoxified by red palm oil.
Like other edible leaves, cassava leaves are processed into leaf
protein concentrate (LPC) which is one of the ways of addressing the
world protein needs. Many other foods are processed into various
products – the processing methods of which vary with the types of food
materials being processed. At the industrial or commercial level, many
food industries are involved in the processing of food materials into
various products. Some examples are
(i) the processing of malted barley or cassava, cereal adjuncts and
hops used in the manufacture of lager beer in the brewing
industry
(ii) the degumming of fats and vegetable oils with dilute sodium
chloride solution (brine) to remove gum particles, resins and
proteins which are nutrient sources for microganisms and the
hydrogenation of the oil in the presence of nickel catalyst at 160-
0
220 C to manufacture margarine.
- CH = CH - H 2 , nickel catalyst - CH 2 - CH 2 -

unsaturate d fat 160 - 220 0 C saturated fat

(margarine)

(iii) The processing of cassava to produce industrial starch used in

laundry services
(iv) The processing of wheat into flour used in baking of bread,
biscuits etc by the baking industry.
(v) The processing of palm oil or palm kernel oil into vegetable oils.

14
Merits of Food Processing
(i) The manufacturers and suppliers of processed foods enjoy higher
profit since mass production of food is much cheaper than
individual production of meals from raw materials.
(ii) Food processing increases seasonal availability of foods and
enables transportation of delicate and perishable foods such as
tomatoes across long distances.
(iii) Processing results in better food preservation, reduces the tasks
of marketing and distribution and increases food consistency.
(iv) Through processing, toxic factors in foods as well as spoilage and
pathogenic microbes are removed thereby making such foods
safe to eat.
(v) Without modern food processing techniques, supermarkets and
long voyages would not be feasible.
(vi) Processed foods are less susceptible to spoilage than fresh foods,
and are suited for long distance transportation from the
producer to the consumer. Fresh plant and animal foods are
more likely to harbour pathogenic microbes such as Salmonella
typhii and Clostridium botulina capable of causing illnesses.
Demerits of Food Processing:
(i) Generally, unprocessed foods contain higher percentage of
naturally-occurring vitamins, minerals and dietary fibre than
processed foods. Heat processing for instance, destroys vitamins
A and C and hence, canned fruits have a lower content of these
vitamins than fresh fruits. It is advisable to consume more of
natural foods with low level of toxicants.
(ii) Food processing can lower the nutritional value of foods, and
introduce contaminants not naturally associated with the food
materials.
(iii) Processed foods contain some additives (stabilizers, flavouring
and texture-enhancing agents) which have little or no nutritive
value, or preservatives (nitrites etc) added to extend the shelf-life
of commercially available food products which may affect the
health of the consumers.
(iv) Processed foods usually have a higher ratio of energy to other
essential nutrients than unprocessed foods – a phenomenon

15
 called “empty calories”. Most often, mass produced processed
food products are the so called junk foods to satisfy consumer
demand for convenience.

Effect of Processing on the Nutrient Composition of Foods

Processing increases food digestibility, palatability, keepability and
safety. Cooking causes food sterilization, starch solubilization, food
availability and reduces soluble nutrients (sugars, minerals, vitamins and
amino acids of proteins) which are lost to the cooking water when
discarded.
Boiling or cooking of yam results in the removal of free amino
acids, a reduction in the mineral (P, Mg, Fe, Na, Ca, etc) levels, but
increases the availability of proteins and carbohydrates in cocoyam
tubers. Moisture content of roots and tubers generally increase with
0
boiling (98 ± 2 C), but baking which occurs at a higher temperature of
0
about 205 C decreases moisture level in foods. Ash content of foods is
decreased by boiling due to loss of water-soluble minerals (Na, K, P, S)
when the boiling water is discarded.
There is inevitable losses due to processing and cooking and
both have positive and negative effects on the nutritional value of foods.
For instance, cooking improves the digestibility of proteins and starches
and destroys the toxicants in foods, but there is inevitable leaching of
nutrients into the cooking water that is sometimes discarded.
Nutrients can be lost from food intentionally as occur when
cereals are milled, vegetables are peeled or individual nutrients are
extracted from raw materials, and also by inevitable processing methods
such as blanching, sterilizing, cooking and drying of foods (Henry and
Massey, 2001). They also reported accidental or avoidable losses due to
inefficient processing or storage systems and that milling (mechanical
separation of the endosperm from the germ, seed coat and pericarp)
results in losses in B-vitamins, iron and calcium in cereals. For nutrient
losses, Henry and Massey (2001), further reported that
(i) Commercial milling removes 68% thiamine (Vit. B 1), 58-65%
riboflavin (Vit. B2) and 85% pyridoxine (Vit. B6) from whole
wheat, and also reduces the levels of zinc and iron.

16
(ii) Milling results in beneficial loss of phytic acid (Kent, 1974). The
phytic acid forms insoluble complexes with calcium and iron,
thereby reducing the bioavailablity of these minerals. The
reduction in phytic acid level through milling may improve the
bioavailability of the remaining nutrients.
(iii) Milling and polishing of rice results in nutrient losses.
(iv) Washing and peeling of fruits and vegetables result in loss of
water-soluble vitamins B and C since these vitamins are more
concentrated in the peel and outer layers. To reduce losses of
vitamins and minerals, peeling of roots and tubers should be
minimized without affecting palatability.
(v) Blanching which is used to inactivate enzymes before vegetables
are preserved is carried out by immersion in boiling water or
treatment with hot air or steam results in loss of water-soluble
nutrients such as mineral salts, proteins, sugars and vitamins.
Higher losses occur on foods with large surface to volume ratio.

Effect of Processing on Toxicants in Foods

Processing, by whatever method, generally reduces to physiologically
tolerable levels, the concentrations of toxicants found in natural or
synthetic association with foods thereby making the foods safe for
utilization by humans. For instance, calcium oxalate causes acridity and
scratchiness that is irritating to the digestive tract, and can result in
death when raw or not well cooked cocoyam is eaten. When ingested in
high concentration by the consumer whose life is in his hands, the
calcium oxalate crystals can cause the deposition of kidney (renal)
2+
stones/calculi. Oxalate binds minerals especially divalent cations (Mg ,
2+ 2+
Ca , Zn ) making them unavailable for utilization by the body for
growth.
Today, all roads lead to India, Germany and the United States of
America for the use of laser to crush kidney stones instead of the delicate
surgery that one is not sure of in Nigeria. In addition to avoiding foods
that contain high levels of oxalic acid, water therapy is also
recommended from time to time.

17
 Bean shaped kidney cortex
where urine is produced

Kidney stone imparted on the

wall of the urethra
Urethra

Bladder

Simple processing methods that remove antinutrients in foods have

significant impact on nutrient bioavaidability, and should be encouraged
as part of the routine processing of food samples. The cyanogenic
glycosides (linamarin, lotaustralin and amygdalin) in cassava, when
hydrolysed by the enzyme linamarase, produce toxic hydrogen cyanide
(HCN). Cyanide blocks oxidative phosphorylation (Osuntokun, 1973) by
inhibiting cytochrome C oxidase responsible for electron transport from
+
NAD to molecular oxygen to form water thereby hindering respiration
and resulting in death. The lethal dose of HCN when taken by mouth is
0.50-3.30 mg/kg body weight and the concentrations of HCN (mg/kg) in
cassava and their consequences are shown in Table 1.

Table 1: Concentrations of hydrogen cyanide (HCN) in cassava and

implication
Concentration of HCN Consequence
(mg/kg cassava)
0 – 50 Harmless
51-80 Slightly toxic
81 – 100 Toxic
Above 100 Fatal
Source: Montgomery (1980).

18
The level of HCN in cassava and similar food products can be reduced by
post harvest processing involving peeling, washing, soaking,
fermentation, boiling, frying and roasting which result in the production
of various cassava products such as loi-loi, garri, tapioca etc.
Most legume seeds provide a valuable source of proteins in the
diet of the world’s poor as they contain 20-40% protein on dry matter
compared to cereals which contain 7.0 – 15% protein. Processing, to
remove antinutrients in legumes is an important step in the preparation
of most legume diets.
When foods are exposed to heat (high temperature) and light,
the nutrient fats and vitamins B1, D and E are easily oxidized and
destroyed. Vitamin A is very heat labile and is easily destroyed and
oxidized by heat. When exposed to heat and light, carotene oxidizes,
isomerizes and get destroyed. Folic acid is destroyed by the use of copper
utensils and its level in foods decreases with storage/prolonged heating
and is lost in cooking water when discarded. Vitamin C level decreases
during storage, heating, drying, oxidation and cell damage such as
chopping or slicing of food. The denaturation of proteins by heat
treatment improves protein digestibility and retains amino acid
composition because of heat inactivation of antinutrients such as trypsin
inhibitors (Onyeike et al., 1991). Riboflavin (vitamin B 2) and niacin
(vitamin B3) are stable to heat. Reducing sugars (glucose, mannose,
galactose and lactose) in foods react with some amino acids such as
lysine during non-enzymatic browning (Maillard reaction) to form an
indigestible complex, and thus reduce the protein quality of the food.
Heat processing causes the dehydration of food samples thereby
decreasing the moisture content and increasing the concentration of
other nutrients.

Salting of meat and fish prior to smoking causes the exudation of liquid
containing water soluble protein, vitamins and minerals from the flesh,
and the salt denatures the proteins resulting in increased protein
digestibility.
Smoking of meat and fish to make them dry is bacteriocidal and
reduces oxidative changes in fats (rancidity), proteins and vitamins, but

19
causes nutrient losses due to heat involved; flow of gases and interaction
of the components of smoke with proteins.

Food Preservation
Food preservation is the process of treating and handling food in order to
stop or greatly slow down its spoilage (loss of quality, edibility or
nutritive value) caused or accelerated by microbes. Preservation usually
involves preventing the growth of bacteria, fungi and other
microorganisms, as well as retarding the oxidation of fats which cause
the fats and oils to become rancid (Wikipedia, 2009). It also includes
processes to inhibit natural ageing and discolouration that occurs during
food preparation such as the enzymatic browning when yams, cocoyams
and apples are cut open.
Common methods of preservation include drying, spray drying,
freeze drying, vacuum packing, canning, preserving in syrup, food
irradiation and adding preservatives or inert gases such as CO 2. Pickling,
salting, smoking, preserving in alcohol, curing and sugar crystallization
are other methods that add flavour to food in addition to preserving it.
The principles of food preservation are based on the knowledge
of agents that cause food spoilage and how to prevent deterioration, and
how biological and chemical reactions, physical agents and attack by
insects, rodents and microbes bring about reduction in food quality.

Methods of Food Preservation

There are two main methods of food preservation namely physical and
chemical.

Physical Methods
i) Cold preservation: Here, changes which occur in food and
affect palatability and result in spoilage are slowed down. In
preservation by freezing, the temperatures used freeze or kill the
cells leading to greater keepability since enzymes no longer have
aqueous environment for activity that lead to food decay. Frozen
cells (foods) retain their enzymes but activity that lead to
decomposition is retarded. Freezing methods include slow

20
 freezing of packaged and unpackaged foods in still cold air; quick
freezing in rapidly moving air of high relative humidity; contact
freezing in cold brine where temperature is close to the freezing
point of the salt solution; indirect freezing in cans dipped in
0
freezing liquids such as propylene glycol at -52 C etc.
ii) Heat preservation: This involves adequate heating at high
0
temperatures (100 C and above) in hot water, steam or
autoclaves to destroy microbes and prevent food decay.
0
Sterilization occurs at 100-130 C and is suitable for foods whose
structure and consistency are not affected by high temperature.
Such foods include meat, fruits and vegetables. Pasteurization
0
occurs at temperatures below 100 C and is used for juices, milk
and fish whose protein and vitamins would be destroyed by
higher temperatures used for sterilization.
iii) Vacuum packing: This method stores food in a vacuum
environment in air-tight canisters, plastic bags or bottle or pack
and presenting it for sale. The vacuum environment removes
atmospheric oxygen, protecting the food from spoilage by
aerobic bacteria, fungi and preventing evaporation of volatile
components. Vacuum packing is used for long term storage of
dry foods (nuts, cereals, coffee, smoked fish, cured meat, cheese)
and fresh foods (meat, vegetables, soups). Here, the food is
stored in an airless environment and bacteria are stripped of
oxygen needed for survival. This method is used to store nuts to
reduce loss of flavour.
iv) Drying: The aim of drying is to withdraw water from food
(dehydration) to significantly reduce water activity in order to
inhibit chemical and enzymatic reactions and delay/stop growth
of microorganisms. Drying reduces weight and makes food more
portable and ensures the retention of other nutrients. Foods that
can be dried include fish, meat, cereal, grains, legume seeds,
fruits (apples, pears, paw-paw, mangoes, banana, coconut,
grapes, etc). In vapourization drying, water is removed from food
to produce dry product at low temperature and pressure, while
evaporation drying occurs at temperature and pressure close to
the boiling point of water. Vacuum drying is an evaporation

21
 drying under vacuum. In contact drying, liquid foods are
converted into powdered food using warmed rollers or driers.
Freeze drying is mainly an industrial method in which water in
food is frozen and passed directly from solid to gaseous state and
here, sensitive substances and aroma are preserved. Freeze-dried
foods include meat, fish, milk, eggs, fruit juices, greens, onions,
soup, coffee, potatoes, etc.
v) Irradiation of food: This is the exposure of food to ionizing
radiation, either high energy electrons or x-rays, from Van der
Waal accelerators or by gamma rays emitted from radioactive
sources such as Cobalt-60 or Caesium-137 to destroy
microorganisms (bacteria, virus) or insects that might be present
in the food. Other effects of this treatment include inhibition of
sprouting as in yams, delay of ripening, increase of the yield of
juice, destruction of bacteria, moulds, insect pests and at higher
doses causing sterility. It is also called cold pasteurization as the
food is not heated. Because ionizing radiation is hazardous to
life, irradiation facilities have a heavily shielded irradiation room
where the process takes place. Scientists are protected from
receiving radiation dose from the facility. Irradiated foods do not
become radioactive and national and international expert bodies
(FAO and WHO) have declared food irradiation as wholesome,
but the wholesomeness of consuming such food is disputed by
opponents (Hauther and Worth, 2008) and consumer
organizations (Consumer International, 2009). However, it is
estimated that in more than 40 countries, about 500,000 tons of
food items are irradiated per year world-wide, and these are
mainly spices and condiments with an increasing segment of
fresh fruit irradiated for fruit fly quarantine (American Diet
Association, 2000; Deeley et al., 2006 and Kume, 2009).

Radiation Absorbed Dose

Dose is the physical quantity governing the radiation processing of food,
relating to the beneficial effects to be achieved (Wikipedia, 2009). The
dose of radiation is measured in the S.I. unit known as Gray (Gy), and
one Gy dose of radiation is one joule of energy absorbed per kilogram of

22
food material. In radiation processing of foods, the doses are generally
measured in kilo Gray (K Gy) or 1000 Gy. Dosimetry is the measurement
of radiation dose.

Table 2. Radiation dose and applications in foods

Radiation Application
i. Low dose up to - sprout inhibition in bulbs and tubers 0.03-
1 KGy 0.15 K Gy.
- Delay in fruit ripening 0.25-0.75 K Gy
- Insect disinfestations 0.07-1.00 K Gy.
ii. Medium Dose - Reduction of spoilage microorganisms to
1 KGy to 10 KGy prolong shelf-life of meat, poultry and
seafoods under refrigeration 1.50-3.00 KGy.
- Reduction of pathogenic microbes in fresh
and frozen meat, poultry and sea foods 3.00-
7.00 KGy
- Reducing the microbial population in spices
to improve the quality of hygiene 10.0KGy.
iii. High Dose - Sterilization of packaged meat, poultry and
Above 10KGy their products which are shelf stable without
refrigeration 25.0-70.0KGy.
- Sterilization of hospital diets 25.0-70.0 KGy.
Source: Wikipedia (2009)

Chemical Methods of Food Preservation

i. Salting or curing: A food sample such as meat is treated with
salt which removes water from it by osmosis thereby preserving
the food. Nitrates and nitrites (also used as additives) are used to

23
 cure meat and inhibit the action of Clostridium botulinum that
causes spoilage.
ii. Pickling: Here, food is preserved in an edible anti-microbial
liquid that inhibits or kills bacteria and other microbes.
Examples of pickling agents are alcohol, vegetable oil, brine and
vinegar while chemically pickled foods include eggs, corned beef,
cucumbers, pepper, etc.
iii. Sugaring: In this method, sugar is used to preserve fruits such as
apples, citrus fruits, pears either in syrup with the fruit or in
crystallized form where the preserved food is cooked in sugar to
the point of crystallization.
iv. Use of lye or sodium hydroxide: This makes food alkaline for
microbial growth and the alkali saponifies fats and oils in the
food resulting in flavour and texture changes.

v. Jugging: This is the process of stewing food such as meat or fish

cut into pieces in a covered earthen-ware or tightly-sealed jug
with brine and stewed. Red wine and/or the animal’s own blood
may be added to the cooking liquid.
vi. Jellying: This is the preservation of food by cooking in a material
(gelatin, agar or maize flour) that solidifies to form a gel. Some
foods such as meat form protein gel. Fruit preserved by jellying is
known as jelly, marmalade or fruit preserves, and the jellying
agent is usually pectin added during cooking or arising naturally
from the fruit.
vii. Potting: In this method, the food is set in a pot and sealed with
a layer of fat. Potted foods include meat, liver, chicken, shrimp
and other sea foods etc.

Reasons for which Foods are Preserved

i. To prevent spoilage and production of toxins.
ii. To prevent nutrient losses. Milk exposed for a long time turns
turbid and sour due to action of lactic acid bacteria while edible
oil undergoes rancid if not preserved.
iii. To make food available all the year round to feed the hungry
people of the world and reduce starvation and acute food
shortage.

24
Commonly used Preservatives
i. Sorbic acid: CH3CH = CH – CH = CHCOOH
it inhibits yeasts and moulds in bread without affecting smell,
flavour and structure of foods and is physiologically safe.
ii. Benzoic acid and sodium benzoate
COOH COONa

They preserve acid foods such as fruits, jams, fruit drinks,

vegetables, fish and egg products.
iii. Propionic acid, CH3CH2COOH
it is effective against microbes and prevents mouldiness in bread.
iv. Sulphur(IV)oxide SO2 inhibits enzymic processes and browning
reactions. It is used to preserve meat, wine and fruits.
v. Pyrocarbonic acid diethylether preserves wine, beer, fruit drinks
and is effective against lactic acid bacteria, yeast and mould.
vi. Nitrite inhibits the action of Clostridium botulina (bacteria) and
contributes to the flavour of cured meat.
vii. Parahydroxybenzoic acid
COOH

OH
It has antimicrobial effect on foods.
viii. Biphenyl

This preserves citrus fruits.

Effects of Preservatives on Foods

25
Preservatives affect food colour. H2SO3 and SO2 cause bleaching.
Sometimes the taste and smell of the preservative may be transferred to
the food to be preserved. Gases used to preserve foods can be absorbed
by the latter bringing about secondary reactions between the food and
the preservative resulting in changes in food flavour. Oxidizing
preservative such as H2O2 may destroy vitamins A and C in foods which
are sensitive to oxidation. However, these effects of preservatives on
foods are negligible unless excessive or uncontrolled
concentrations/amounts of preservatives are used.

Genetically Modified Organisms (GMOs)

Any organism (animal, plant or microbe) whose genetic material has
been altered by means of genetic engineering techniques is referred to as
a genetically modified organism (GMO). The GMOs include animals,
plants/crops and microorganisms and are the source of genetically
modified foods and are widely used in scientific research and to produce
goods other than food (Wikipedia, 2012).

Genetic Modification: This involves the insertion or deletion of genes.

When genes are inserted, they usually come from a different species
(horizontal gene transfer). Transfer of gene occurs by (i) Penetration of
the cell membrane by DNA for any reason (ii) Artificial attachment of the
genes to a virus (iii) Physical insertion of the extra DNA into the nucleus
of the intended host with a very small syringe or with very small particles
fired from a gene gun (Johnston and Tang, 1994).
The general principle of producing a genetically modified
organism (GMO) is to add new genetic material into an organism’s
genome. This is called genetic engineering, and was made possible
through the discovery of DNA and the synthesis of the first recombinant
DNA molecules by Paul Berg in 1972 (Jackson et al., 1972).

History of Genetically Modified (GM) Plants/ Crops

It was first discovered that DNA can transfer between organisms
(Lederberg and Tatum, 1946), and the first genetically modified plant was
produced in 1983 using an antibiotic-resistant tobacco plant. In 1994, the
transgenic Flavr Savr tomato was approved by the Food and Drug
Administration (FDA) for marketing in the US – the modification

26
allowed the tomato to delay ripening after picking. Hence, it was in 1994
that the commercial sale of GM foods began when Calgene first marketed
its Flavr Savr delayed ripening tomato (James, 1996). The transgenic
crops in the US which received approval for marketing in 1995 were
(i) Canola with modified oil composition (Calgene)
(ii) Bacillus thuringiensis (Bt) corn/maize (Ciba-Geigy)
(iii) Cotton resistant to the herbicide, bromoxynil (Calgene)
(iv) Bt cotton (Monsanto)
(v) Bt potatoes (Monsanto)
(vi) Soybeans resistant to the herbicide, glyphosate (Monsanto)
(vii) Additional delayed ripening tomatoes (DNAP, Zeneca/Peto, and
Monsanto) (James, 1996).

By 2011, the United States leads the list of countries in the production of
GM crops and foods and 25 GM crops had been granted regulatory
approval to be grown for commercial purpose (James, 2011).

Method of Production of GM Plants/Crops

GM crops or biotech crops are plants, the DNA of which has been
modified using genetic engineering techniques which are then used in
agriculture. Methods of producing GM plants are
(i) Transgenesis: Transgenic plants have genes obtained from
another species inserted into them. These plants have been
engineered for research to form new colours in plants and to
make different crops.
(ii) Cisgenesis: Cisgenic plants are made using genes from the same
species or a closely related gene where conventional plant
breeding can occur. Cisgenesis is useful for plants such as
potatoes that are not easy to crossbreed by conventional means,
and these plants should not require the same level of legislation
as other GMOs (Mackenzie, 2008).

When plants are produced and seeds obtained, the seed producer
(Company/Industry) will apply for regulatory approval to field-test the
seeds. If field test is successful, the Company will then seek regulatory

27
approval for the crop to be marketed. Once approval is given, the seeds
are mass produced and sold to farmers. The farmers will produce GM
crops which contain the inserted gene and its protein product. The
farmers then sell their crops as commodities into the food supply market
in countries where such sales are permitted.

Genetically Modified (GM) Animals

The process of genetically engineering animals is slow, tedious and
expensive. Many animals have been genetically engineered for various
purposes. For example
(i) Green Fluorescent Protein (GFP) for medical research purposes
for which Chalfie, Shimoura and Tsien (2008) were awarded the
Nobel Prize in Chemistry.
(ii) A Japanese-American Team produced green-flourescent cats
inorder to find therapies for HIV/AIDS and other diseases
(Wongsrikeao et al., 2011).
(iii) Targeting Parkinson’s disease, scientists in Japan successfully
transferred a gene into a primate species (Marmosets), and
produced a stable line of breeding transgenic primates for the
first time (Sasaki et al., 2009; Schatten and Mitalipov, 2009).
(iv) Pigs have been engineered to produce omega-3 fatty acids
through the expression of a roundworm gene (Lai et al, 2006),
and goats have been genetically engineered to produce milk with
strong spiderweb-like silk proteins (Zyga, 2010).
(v) In China, scientists have produced dairy cows genetically
modified with genes for human beings to produce milk that
would be the same as human breast milk (Stevenson, 2011), and
this is of benefit to mothers who cannot produce breast milk
which they want their babies to have rather than the use of
infant formula.
(vi) Transgenic animals have been developed that produce human
therapeutics or biotherapeutics (Houdebine, 2009).
(vii) GM fishes are used for research in genetics and as pets. They are
being considered as food and as aquatic pollution sensors.

Genetically Modified (GM) Mammals

28
GM mammals are a category of GMO (EFSA, 2012) and include GM pigs,
rats, mice, rabbits, sheep and these were the first GM Models of human
disease including the first carcinoma caused by a transgene.

Genetically Modified Microorganisms

Bacteria have been genetically engineered (Melo et al., 2007) and are
important in producing large amounts of pure human protein for
medicinal purposes (Leader et al., 2008). Also genetically modified
bacteria are used to produce insulin used to treat diabetes mellitus
(Walsh, 2005). The enzyme alpha-amylase from GM bacteria is used to
convert starch to simple sugars and fungal pectinesterase has been
engineered to improve the clarification of fruit juice (Panesar et al., 2010).

Genetically Modified Foods

Genetically modified foods also known as GM foods or biotech foods are
foods obtained from GMOs such as GM crops or GM fish. The GMOs
have their DNAs altered by genetic engineering techniques which are
much more precise (King, 2003) than mutagenesis (mutation breeding)
where an organism is exposed to radiation or chemicals to create a non-
specific but stable change. Humans can also modify food organisms by
selective breeding, plant breeding or animal breeding other than by
genetic engineering.
Typically, GM foods are genetically modified (transgenic) plant
products such as soybean, corn, cotton seed oil, and golden rice which
contains beta carotene – a precursor of vitamin A. Golden rice was the
first GM crop in which an entire biosynthetic pathway was engineered,
for faster growth, resistance to pathogens, increase in nutrient value or
any other beneficial purpose. Although GM livestock have been
developed experimentally, as at July 2010, none are currently on the
market
(http://www.fda.gov/animalveterinary/developmentapprovalprocess/gen
eticengineering/geneticallyengineeredanimals/ucm113672.htm).

Foods Made From GM Crops/Plants (Wikipedia, 2012)

(i) Paw-paw has been engineered to resist the deadly ringspot virus,
and save the Hawaiian Papaya Industry from collapse in 1990.
Today, 80% of Hawaiian Carica papaya is genetically engineered,

29
 and there is still no conventional or organic method to control
ringspot virus (Ronald and McWilliams, 2010).
(ii) Most vegetable oils used in prepared foods in the U.S are
produced from GM crops (corn, soybeans, canola) and are sold
to consumers as cooking oil, margarine and shortening
(Michelle, 2011).
(iii) Canola, of which 93% of the U.S crop is genetically engineered to
resist the herbicides glyphosate and glufosinate and for
improved oil composition is used to produce vegetable oil
(approximately 43% of the canola seed is oil) (Soyatech.com).
(iv) About 95% of the U.S soybeans is GM and approximately 85% of
the world’s soybean crop is processed into soybean meal and
vegetable oil (Soyatech.com).
(v) In U.S, maize is known as corn. Maize is a staple food in many
parts of the world, and 86% of U.S maize was GM in 2010 (NASS,
2010). In 2011, 32% of maize crop world-wide was GM, 49% was
used for livestock feed, 27% went to ethanol production, 13% was
exported while 4.1% of the U.S corn harvest was made into high
fructose corn syrup, and the rest was used for other sweetners,
corn starch, alcoholic beverages.
(vi) Cotton crop: About 93% of the U.S cotton crop is GM and the
cottonseed oil produced is used as a salad and cooking oil, both
for industrial and domestic purposes (National Cottonseed
Producers Association, n.d.)
(vii) About 95% of the sugar beet acres in the U.S. were planted with
glyphosate herbicide – resistant seeds (James, 2011). Sugar beets
that are herbicide-resistant have been approved for the
production of refined sugar (sucrose) in countries like USA,
Mexico, Singapore, Korea, Japan, Canada and Colombia.

Foods from GM Animals

As of September 2012, no genetically modified animals had been
approved for use as food, but a GM Salmon was near U.S Food and Drug
Administration approval at that time (Andrew, 2012).

Controversies around Genetically Modified Foods

Criticisms around GM foods have centered on

30
(a) The issue of the safety of the food produced from GM crops
(National Research Council, 2004) for consumption, ecological
concerns and economic concerns raised by the fact that GM
plants (and potentially animals) that are food sources are subject
to intellectual property law and market dynamics.
(b) Whether
(i) The food should be labeled and if so, how.
(ii) Agricultural biotechnology (GM crops) are needed to
address the world food crisis and hunger now or in the
future.
(iii) Environmental effects of GM food crops have been
adequately considered to permit the consumption of
such foods.
(iv) It is ethical to make GM organisms and GM foods.
(c) Some critics argue that GM crops which have been used mainly
to produce animal feed do not address the problem of hunger
and poverty. The report of the recent International Assessment
of Agricultural Knowledge, Science and Technology for
Development (IAASTD) showed that there were no conclusive
evidence that GM crops have increased yields, and that GM
soyabeans for example, suffer from “yield drag” resulting in a 5-
10% reduction in yield (Friends of the Earth, 2008). It was further
argued that as yet, no GM crops modified to increase yield or
resist drought are on, or even close to the market; instead crops
have been modified to be resistant to insect pests and tolerant to
herbicides resulting in increased use of chemicals to deal with
the weeds that develop resistance to the chemicals over time.

Plate 1. GM Honeysweet plum. These transgenic plums contain a gene that makes them
highly resistant to plum pox virus

31
Source: http://www.ars.usda.gov/is/br/plumpox/12/11/2012

Nutrition
Nutrition is the provision of food to living organisms in order to support
life. The condition or health of the body depends on nutrition, and hence
the latter is not merely food nor that which nourishes. Food is the
substance of nourishment, while nutrition is the act of using food in a
series of coordinated processes whereby the nourishment/aliment of the
body is effected. Nutrition is the science of food values or the study of
food, its properties and the ways the body utilizes it to produce energy
used to do all forms of biological work and for growth and maintenance
of tissues and mental development. Nutrition can be looked at in the
context of the types of atoms and molecules present in foods, their
reactions and effects on human and animal subjects consuming such
foods.
A primary purpose of the function of nutrition is to establish and
sustain the structure and function of all organs and parts of the body, to
keep the mechanism of the body in order and prevent disease.

History of Nutrition Science

This dates back to about 400 B.C, when food was just considered as food.
You got hungry; you ate. Hippocrates, the “Father of Medicine” said to
his students, “Let food be thy medicine, and medicine thy food”, and that
“a wise man should consider that health is the greatest of human
blessings”. Foods were often used as cosmetics or as medicines in the
treatment of wounds. One story described the treatment of eye disease,
now known to be due to a vitamin A deficiency, by squeezing the juice of
liver unto the eye. Vitamin A is stored in large amounts in the liver. No
one really understood what was good for you or why, at least not in a
physiological, scientific way, and Physicians attempted to prescribe diets
as remedies for illness, (McKenney, 2009).
Foods which may be in solid or liquid state were then classified
as hot, cold, wet or dry based on an association with one of the four
classical Greek elements namely fire, air, water, earth. It was believed
that these qualities of food interacted to create “humors” within the
body. For example, cold and dry interact to create “black bile” (a humor),
which was blamed for liver problems and would be treated with a diet of

32
hot and wet foods. Nutrition science continued in this way for many
centuries, but today, we understand our diet as the source of six major
nutrients namely carbohydrates, fats, proteins, water, vitamins and
minerals.

Nutrients
These are constituents of food that allow the organism to grow, maintain
itself and function normally. A nutrient is a chemical substance required
by an organism to live and grow, and is used in an organism’s
metabolism. Nutrients enrich the body, build and repair worn out
tissues, give heat and provide energy to enable the body function
efficiently and regulate body processes. Methods for nutrient intake vary
with animals consuming foods that are digested by enzymes, but most
plants ingest nutrients directly from the soil via their roots or from the
atmosphere.
Nutrients needed in relatively large amounts are called
macronutrients. Examples are carbohydrates, proteins and fats which are
organic nutrients. Water is also consumed in large quantity but is not
always considered as nutrient when consumed in isolation. Salt (sodium
chloride), calcium (Ca), potassium (K), Magnesium (Mg), Phosphorous
(P) and Sulphur (S) are usually added to the list of macronutrients
because they are required in large quantities compared to other minerals.
Nutrients required in relatively small quantities are called
micronutrients and they include the remaining minerals and then
vitamins (both water-soluble and fat soluble).

Classes of Nutrients in Foods, Sources and their Functions

There are six major classes of nutrients, namely carbohydrate, fats,
proteins, water, vitamins and minerals.

Table 3a: Energy-giving nutrients, their sources and functions

Nutrient Sources Functions
1. Carbohydrates – the two Tubers (yam, (a) Source of energy (4.20 Kcal/g)
components are cocoyam), grains to do biological work
nitrogen-free extractive (wheat, rice, (b) Building block for other
(soluble sugars, starches) maize), bread, nutrients and dietary excess stored

33
 and crude fibre (mainly potatoes, as glycogen.
cellulose) spaghetti, candy,
pastries.
2. Fats (Lipids) – they are Oils from fish, (a) Keep cell membranes
composed of fatty acids soybean, castor, functioning.
bonded to glycerol. lard or tallow from (b) Rich and cheap source of
Mono- or poly livestock. energy (9.10 Kcal/g) which is twice
unsaturated fats are the energy content of 1.0g of
liquid fats which are carbohydrate or protein.
healthier (e.g. olive oil) (c) Source of heat to the body
than saturated fats or (d) Insulate body organs against
solid fat such as butter, shock thus protecting them
lard, at room (e) Helps to keep body
temperature temperature constant and maintain
healthy skin and hair.
3. Proteins: True protein is Fish, eggs, meat, (a) Source of energy (4.10 Kcal/g)
made up of amino acids. legume seeds, soy and essential amino acids.
Crude protein contains products, (b) Basic structural unit required in
true protein and other microorganisms metabolism and in production of
nitrogenous products or (single cell DNA, antibody and hormones.
non-protein nitrogen (N- protein), dairy Hormones are secretions of
PN), while N-PN can be products (milk, ductless glands important in
converted to true protein cheese, etc). metabolic regulation.
by rumen bacteria for
ruminants.

34
Table 3b: Non energy-giving nutrients, their sources and functions
1. Water (a chemical Rain, borehole/ (a) Functions in transport,
compound made up of ground water, chemical reactions,
hydrogen and oxygen in rivers, seas and lubrication and the
the ratio of 2:1, and oceans. maintenance of body
whose molecules are temperature.
held together by (b) A cell deprived of
hydrogen bonds. water gets dehydrated
resulting in electrolyte
imbalance and death.
(c) H2O is an essential
nutrient, and the solvent
in which all the chemical
reactions of life take place.
(d) Water is also a coolant
2. Vitamins Sources include (a) Metabolic functions
There are two classes vegetables, fruits, and as coenzymes in
namely: etc. enzyme reactions.
(i) Fat-soluble vitamins (b) They regulate
A,D,E and K called metabolic reactions and
ADEK. help to ensure healthy
(ii) Water soluble living.
vitamins B (B1, B2, B3, B5,
B6, B12 and C).
3. Minerals – these are Sources are fruits, (a) Involved in protein
inorganic substances vegetables, nuts synthesis, as component of
that originate from and seeds. skeleton, oxygen
rocks and ores which transport, fluid and acid-
enter the food chain base balance in the body
through the soil. There and as cofactor for
are two classes namely enzymes.
(i) Major minerals (Na, (b) Ca, Mg and P are the
Mg, Ca, P, Cl, K, S) major constituents of bone
(ii) Minor (trace) and teeth.
minerals such as Co, Cu, (c) Other minerals are
F, I, Fe, Mn, Mo, Se, Zn needed for various
Humans get minerals by biochemical processes
consuming plants grown occurring in the body.
on mineral-rich soils or
by eating animals that

35
 feed on these plants.
Note: Each of carbohydrate and protein contains 4 kcal/g of energy, fat
contains 9 kcal/g while ethanol (an alcohol) has an energy content of 7.0
kcal/g. This may in part, account for why some individuals who wish to
engage in strenuous physical activity may like to drink a big bottle of an
alcoholic beverage (stout).

Essential Nutrients
An essential nutrient is one required for the normal functioning of the
body that either cannot be synthesized by the body at all, or cannot be
synthesized in amounts adequate for good health, and thus must be
obtained from an external dietary source (Wikpedia, 2010). Water and
oxygen are essential for human health and life, because oxygen cannot be
synthesized by the body and water is not formed in sufficient amounts.
Water is used as a solvent, carrier, coolant and integral polar structural
member, but both oxygen and water are not often included as nutrients
or food when consumed in isolation (Wikipedia, 2010). Most mammals
make their own vitamin C, and the latter is hence not considered an
essential nutrient for such species, but ascorbic acid is an essential
nutrient for human beings who cannot synthesize it and thus require
external source of the ascorbic acid. Types of essential nutrients are those
of amino acids, fatty acids, vitamins and dietary minerals.
The essential amino acids are very important for the body to
function. They are eight of them for adults and ten for children. The
eight essential amino acids for adults can be recognized by the statement
“very important men lose their pride to ladies” for the amino acids valine,
isoleucine, methionine, leucine, tryptophan, phenylalanine, threonine
and lysine. Additional two for children are arginine and histidine. If a
single essential amino acid is missing in a diet, there will be retardation
of growth. They are required by the body during early development and
maturation, pregnancy, lactation and injury.

Note: A complete protein contains all the essential amino acids, while an
incomplete protein source is deficient in one or more of the essential
amino acids.
The amino acid which the body does not recognize its absence
and which it can synthesize is known as non-essential amino acid. The

36
absence of non-essential amino acid in a diet does not affect growth.
Examples of non-essential amino acids are glycine, asparagine, serine,
proline, alanine, cysteine, tyrosine and glutamic acid. Non-essential
substances in foods can have beneficial or toxic effects on health. Dietary
fibre for instance is not absorbed by the human digestive tract, but is
important in digestion and absorption of otherwise harmful substances.
Interest has recently increased in plant chemicals which include many
non-essential substances that may have health benefits (Whitney and
Sharon, 2005).
There are three essential fatty acids which the body cannot
synthesize from other precursors and are important for cardiovascular
health. They are
(i) α-linolenic acid or the shortest chain omega-3 fatty acid (LNA)
which is taken in through marine food sources and serves as a
building block for series 3 prostaglandins (e.g. weakly
inflammatory PGE 3).
(ii) Arachidonic acid (AA) – a building block for series 2
prostaglandins e.g. pro-inflammatory PGE 2.
(iii) Linoleic acid or the shortest chain omega-6 fatty acid (Omega –
6 dihomo-gamma-linolenic acid, DGLA) which serves as the
building block for series 1 prostaglandins e.g. the anti-
inflammatory PGE 1, the shortest chain omega-6 fatty acid. Both
AA and DGLA can be made from omega-6 linoleic acid (LA) in
the human body or can be taken in directly through food.

Very good food sources of essential fatty acids are marine oils, vegetables,
fish and fish oils, soybeans, nuts, walnuts, sunflower seeds, pumpkin
seeds and cotton seed. Both omega-3 and omega-6 long chain
polyunsaturated fatty acids are substrates for a class of eicosanoids called
prostaglandins.
A diet high in saturated fat is harmful to the body, but a diet that
is high in mono- and polyunsaturated fat is less harmful and more
beneficial to health. One’s life is therefore in his hands if he decides to
consume diets high in saturated fat which is not recommendable.
By 2005, about 12 out of the 14 vitamins and 12 out of 18 minerals
were recognized as essential nutrients, because the body cannot

37
synthesize them, and they have to be consumed and absorbed from
diets/external sources. Vitamin D though present in salmon fish, cod
liver oil, eggs, and steroid-containing foods irradiated with ultra violet
(UV) light, is an example of a non-essential vitamin, because it is
synthesized by the body when ultra violet light strikes the human skin.
You are advised not to keep your new-born baby under the sun for
vitamin D, but only in mild sunlight. Vitamin K is synthesized by
intestinal bacteria, and is hence non-essential.
In large amounts, many essential nutrients are toxic while some
can be taken in amounts larger than required without toxic effects as
reported by Pauling (1986). He reported with regard to vitamin B 3, “what
astonished me was the very low toxicity of a substance that has such very
great physiological power; a little pinch, 5mg every day, is enough to
keep a person from dying of pellagra, but it is so lacking in toxicity that
ten thousand times as much can (sometimes) be taken without harm”
(Pauling, 1986).

Nutritional Disorders
Nutritional disorders are nutrient-deficient diseases in humans that are
caused by the consumption of diets that do not meet quantitative
requirements of essential nutrients that ensure good health. These
disorders are associated with chronic malnutrition and may also be
caused by over-eating as in obesity. Excessive consumption of some
nutrients can cause acute poisoning resulting in serious health problems.
For the attainment of good health, since one’s life is in his hands,
appropriate diets which provide adequate amounts of nutrients to meet
physiological requirements and prevent the development of nutritional
disorders are highly recommendable.

Nutritional Disorders: Aetiology, Features, Prevention and Food

Sources of Deficient Nutrients that should be Consumed

ii) Protein-Energy Malnutrition (PEM): This is nutrient

deficiency disorder caused by inadequate intake of protein and
energy-giving foods. It can also be caused by poverty, maternal
malnutrition, infections, ignorance and wrong child feeding
practices. PEM is common in African countries particularly

38
 among infants/children under the age of five years. To prevent
PEM, foods containing protein and energy (beans, meat, fish,
maize) should be consumed and the use of pap, banana and
plantain as main food for children should be discouraged.
Nutrition education is important and there should be dietary
modification, surveillance on infant/child growth monitoring,
improvement in income and balanced diets should be consumed.

Acute Malnutrition
Ch ild re n wh o a re su ffe rin g fro m e xtre me n u tritio n a l d e ficie n cy ma y
fa ll in to o n e o r two d istin ct typ e s, o r ma y o ve rla p b o th :
Kwashiorkor Marasm us
Swollen body, feet Loss of fat, muscle
Poor appetite very hungry
Lethargic, sad Irritable, anxious
Pale fragile skin/hair Skin loose, wrinkled

Kwashiorkor Marasmus
Plate 2. Patients Suffering from Kwashiorkor and Marasmus
Source: www.MAMAProject.org

iii) Kwashiorkor: This is the acute form of childhood PEM caused

by insufficient protein consumption due to low level of protein
in diet, but with sufficient calorie intake. In severe cases it may
lead to death.
Features include growth failure, pedal oedema, severe anaemia
poor apetite, wasting of muscle, dull hair with lack of luster,

39
 irritability and anorexia, swollen scrotum, moon-face which
appears oedemacious, skin changes such as peeling off and
pigmentation, distended abdomen (stomach protrudes) with
small buttocks, enlarged liver with fatty infiltrates, diarrhea,
loose and offensive stool and mental changes. For prevention
and treatment, dietary protein content of foods consumed
should be increased. Dried skim milk, soy ogi, leaf protein
concentrate (LPC) and all forms of animal and plant food
proteins should be used therapeutically to reverse the conditions
that characterize kwashiorkor.

Plate 3. Kwashiorkor sufferers show signs One of many kwashiorkor cases

of thinning hair, edema, inadequate growth, in relief camps during the
and weight loss. The stomatitis on the Nigerian–Biafran War
pictured infants indicates an accompanying Source:
Vitamin B deficiency. http://upload.wikimedia.org/wiki
Sources: pedia/commons/thumb/4/47/Starv
A=http://upload.wikimedia.org/wikipedia/co ed_girl.jpg/200px-
mmons/thumb/4/4d/Kwashiorkor_6180.jpg/2 Starved_girl.jpg
30px-Kwashiorkor_6180.jpg ;
B=http://bio.illinoisstate.edu/jearmst/syllabi/c
assava/cassava8.jpg;
C=http://drugline.org/img/ail/150_151_3.GIF

iv) Marasmus: This is a severe form of PEM that results from

energy deficiency and starvation due to lack of proteins, fats and
carbohydrates that give calorie in diets. It is characterized by
emanciation, reduced body weight, growth failure but no
oedema, severe muscle wasting, less common hair and skin
changes, no mental changes and no fatty infiltration of the liver.

40
 Anaemia is present but less severe. Ribs are prominent and the
face looks like that of old-world monkey; there is diarrhea and
stool is loose but with consistent feature and not offensive.
Patient has good appetite, voraciously hungry, wild awake, less
miserable and irritable. To prevent marasmus, there should be
adequate calorie in the diet of susceptible individuals.

Marasmic patients A marasmic patient A child suffering the effects of

Source:http://en.wikipedia.org/ Source:http://malnutrition911 severe hunger and malnutrition
wiki/Marasmus .webs.com/reality%205.jpg during the Nigerian blockade
Source:http://www.glahaiti.org/comi
ngsoon/user_files/Before%20and%2
0AFter%20photos/Myrlene.JPG

Plate 4: Patients Suffering from Marasmus

v) Marasmic-Kwashiorkor: This is caused by deficiency of both

energy and protein in diets consumed. It is in the middle of PEM
spectrum in which there are both features of kwashiorkor and
marasmus. This disorder can be prevented by consuming diets
that give adequate energy and protein.
vi) Goitre: Goitre is an enlarged or swollen thyroid gland caused by
lack/insufficient iodine in diet and water, and intake of foods
which contain goitrogenic agents. Such foods include cabbages,
turnips and groundnuts.
The thyroid gland produces the hormones thyroxine T4 and
triiodothyronine T3 which are found in the bloodstream. If T4
accumulates instead of being released, the thyroid gland swells resulting

41
in a condition known as goitre. To prevent goitre that is due to lack of
iodine in the diet, iodine replacement is done using iodized salt and
onions in diets. Prevention can also be by eating foods such as fruits,
vegetables, meat, sea foods but avoiding foods containing goitrogenic
agents e.g. cabbage. Nutrition education is important and so, the public
should be enlightened to create awareness that goitre is not an inherited
trait, but a nutrient-deficient disease.

For a small goitre that is not due to a cancerous nodule and the thyroid
gland produces normal amount of T4 and T3, then no treatment is
desired, but if there is cancer of the thyroid, surgery to remove the cancer
and some of the thyroid gland is required (Mulinda, 2007).

Sources: A B C
B
A=http://3.bp.blogspot.com/NeyiMYSRsQY/T4rLjmP5KI/AAAAAAAAAmc/hjFo_P7T_kE/s1600/D
B
SC_0245.JPG
B = http://medicscientist.com/wp-content/uploads/2012/07/GOITERandTHYROIDITIS_thumb.jpg
C = http://goiterpictures.com/images/Goiter-Pic.jpg

Plate 5 Individual s suffering from goitre.

vii) Obesity: This is a medical condition in which excess body fat

accumulates to the extent that it may affect health resulting in
reduced life expectancy (http://en.wikipedia.org/wiki/obesity,
2011). It is one of the leading preventable causes of death in
adults and children world-wide and was sometime in history
perceived in the Western world as a symbol of wealth and
fertility. The less activity one does, the fewer calories he burns
and the higher the risk of becoming obese. Obesity is caused by
excessive intake of fatty foods, carbohydrate, sweetened

42
 beverages and drinks, potato chips and fast foods. It also results
from increased use of medications that can cause weight gain
e.g. antipsychotics and antidepressants, and lack of physical
activity as well as genetic susceptibility. Smoking suppresses
appetite and lowered rate of smoking can make people become
obese. About 12% of people who stop smoking gain a large
amount of weight. In obesity, it is difficult to move about, and
there is arthritis.

The status of individuals susceptible to obesity is determined by the body

mass index (BMI), which is a statistical measurement derived from the
weight and height of the individual. BMI is calculated by dividing the
weight of an individual in kilogram by his height in metre squared.
weight of the individual in kilogram
BMI = = kg / m 2
height of the individual in metre squared
Table 4. Classification of obesity
Classification BMI (kg/m2)
Underweight Less than 18.5
Normal weight 18.5-24.9
Overweight (pre-obese) 25.0-29.9
Class 1 obesity 30.0-34.9 (reduces life expectancy by 4 years)
Class 2 obesity 35.0-39.9
Class 3 obesity Greater than or equal to 40.0
Severe obesity Greater than or equal to 35 or 40 (reduces life expectancy
by 10 years)
Morbid obesity Greater than or equal to 35 or 40-44.9 or 49.9
Super obesity Greater than or equal to 45 or 50
Source: http://en.wikipedia.org/wiki/obesity
The surgical literature breaks down Class 3 obesity into severe, morbid
and super categories whose exact values are still disputed.
Obesity results in mortality and is a risk factor for cardiovascular
diseases, type 2 diabetes mellitus, obstructive sleep, cancer, osteoarthritis
(degeneration of bones and cartilages), stroke, hypertension, high
cholesterol, gall bladder disease and respiratory problems (Wikipedia,
2010).

43
 An obese woman An obese man Obese children
Source:http://www.chilloutpo Source:http://www.topnews. Source:http://www.topnews.i
int.com/images/2009/april/fat/ in/health/files/obesity2_0.jpg n/health/files/obesity2_0.jpg
funny-fat-gigantic01.jpg

Plate 6: Patients suffering from Obesity

Prevention and treatment of obesity can be achieved through

(a) Regular exercise: This helps to burn off excess calories
consumed. Walking a kilometer daily for 15 days in a month is
recommended to enhance one’s mood, reduce anxiety, make the
bones stronger, reduce hypertension and the chance of a heart
attack or stroke.
(b) Diet consumed should be healthier (lower food energy diet). Eat
more fruits, whole grains and vegetables and reduce intake of
carbohydrate and fatty foods.
(c) Treatment can be by use of over-the-counter diet products or
prescription medications for losing weight such as herbal
remedies like Orlistat (Xenical) and Phentermine (Lonamin,
Adipex-P, Fastin) prescribed by the Healthcare Provider. These
drugs are taken indefinitely because as soon as their intake is
stopped, overweight comes back.
(d) Weight Loss Surgery (WLS) or Bariatric surgery can be done for
Class 3 obese individuals with severe, morbid or super obesity to
lose weight. The two most common weight loss surgeries are
Laparaoscope gastric binding and Gastric bypass surgery.

Note that heart disease, cancer, obesity and diabetes are commonly
called “Western” diseases because these maladies were once rarely seen
in developing countries. People whose diets are rich in vegetables, fruits
and whole grains do not suffer from “Western” diseases and diseases of

44
affluence like heart disease and cancer. The United Healthcare/Pacificare
Nutrition Guideline recommends a whole plant food diet and the use of
protein only as a condiment with meals. A National Georgraphic cover
article from November, 2005, entitled “The Secrets of Living Longer” also
recommends for longevity, whole plant food diet.
viii) Hypertension: Blood pressure results from the force of the
heart as it contracts and the resistance of the arteries to blood
flow. Blood pressure is hence the force exerted by the blood
against the walls of the arteries (Leikin and Lipsky, 2003).
Hypertension or high blood pressure (an opposite of
hypotension) is a heart, chronic medical condition in which the
systemic arterial blood pressure is elevated. That is, a sustained
systolic pressure above 140mmHg and/or diastolic pressure
above 90mmHg (Wardlaw, 1999). Systolic blood pressure is
blood pressure in the vessels during a heart beat, while diastolic
blood pressure is the pressure between heart beats. A prevalence
of 36.6% among the 167 million Nigerians has been reported, and
the rate increases with age and is high among Nigerians with
diabetes mellitus (Adedoyin et al., 2008).

Types of hypertension:
a) Primary (essential) hypertension is high blood pressure with no
obvious medical cause and it occurs in 90-95% of the cases
(Carretero and Oparil, 2000).
b) Secondary hypertension (5-10% of the cases) is caused by other
conditions that affect the kidneys, heart, arteries or endocrine
system (Mayo Foundation for Medical Education and Research,
2008).
c) Persistent Hypertension: This is one of the risk factors for stroke,
myocardial infarction, heart failure, arterial aneurysm, and is a
leading cause of chronic kidney failure (Pierdomenico et al.,
2009). Changes in diet and lifestyle can improve blood pressure
control and decrease risk of health complications although drug
treatment is important in patients for whom lifestyle changes are
ineffective or insufficient (Nelson, 2010).

45
d) Resistant hypertension occurs when medications fail to reduce
blood pressure to normal levels (Chobanian et al., 2003).
e) Exercise hypertension is high blood pressure during exercise and
its normal range for systolic values is 200-230mmHg (Klaus, 1987;
Jette et al., 1987).
f) Accelerated hypertension: This is associated with headache,
drowsiness, confusion, disorder of vision, nausea, vomiting.
These symptoms are collectively referred to as hypertensive
encephalopathy (Oppenheimer and Fishberg, 1928). It is caused
by severe blood vessel congestion and brain swelling which can
be reversed if blood pressure is lowered (Papadakis and McPhee,
2008). Symptoms in new borns and infants are failure to thrive,
irritability, lack of energy, seizures and difficulty in breathing,
while in children, there is headache, fatigue, blurred vision, nose
bleeds and facial paralysis (Rodriguez-Cruz and Ettinger, 2010).
g) Diet-related hypertension is caused by high intake of sodium salt
(more than 4g table salt daily). Other causes are high intake of
alcohol, cadmium, lead, saturated fats and a deficiency of
magnesium in diet.

Table 5. Sub-classification of hypertension

Sub-class Range of Systolic Range of Diastolic
pressure (mmHg) pressure (mmHg)
Normal 90-119 60-79
Prehypertension 120-139 80-89
Stage 1 hypertension 140-159 90-99
Stage 2 hypertension ≥ 160 ≥ 100
Isolated systolic hypertension* ≥ 140 < 90
Source: Chobanian et al. (2003)
* This is common in the elderly in which systolic pressure is elevated with normal
diastolic pressure as measured using a sphygmomanometer.

Risk Factors of Hypertension

These are age, diabetes, obesity, heredity, stress, anxiety, high salt diet,
low potassium (potassium balances sodium concentration in the body),
excessive consumption of alcohol which damages the heart by causing
the release of hormones that increase heart rate (Leiken and Lipsky,

46
2003). Smoking is another risk factor because the chemicals in tobacco
can damage the lining of arterial walls and cause the arteries to narrow
thereby elevating the blood pressure

Plate 7. Individuals with diet – related hypertension.

Source: http://www.webmd.com/hypertension-high-blood-pressure/guide/high-blood-
pressure-diet

To prevent or treat diet-related hypertension, avoid high intake of foods

rich in salt, alcohol, cadmium, lead, saturated fats. Ensure high intake of
foods rich in potassium, calcium, phosphorous, magnesium, fibre and
polyunsaturated fatty acids. Nutrition education is important.
ix) Diabetes Mellitus: This is a metabolic disorder of carbohydrate
metabolism which as yet, has no cure, in which glucose is
underutilized. Diabetics either do not produce insulin or
produce very little or their body cells are unable to respond to
insulin (insulin resistance) or recognize and utilize insulin,
leading to hyperglycaemia (high blood glucose). Diabetes is a
major cause of heart disease, erectile dysfunction in men,
blindness, high blood pressure and kidney failure. Diabetics are
25 times more likely to undergo foot and other “lower extremity”
amputations due to circulatory problems. In insulin-dependent
diabetes mellitus (IDDM) or juvenile onset diabetes (Type 1
diabetes), diet is not implicated in the aetiology. In non insulin-
dependent diabetes mellitus (NIDDM) or adult onset diabetes
(Type 2 diabetes), diet is implicated in its aetiology. Gestational

47
 diabetes is a temporary and less common one that occurs during
pregnancy.
Diabetes is caused by lack of insulin due to the destruction of beta cells
of Islets of Langerhans in the pancreas where insulin is produced. The
beta cells can be destroyed by drugs (alloxan or streptozotocin) used to
induce diabetes or by the immune system (a combination of genetic
predisposition and other factors provoke the immune system into
attacking and destroying the cells that produce insulin in the pancreas).
Diabetes occurs when the blood glucose level is 126mg/dl or more after
an overnight fasting (not eating any food). Another cause is defect in the
utilization of insulin by the liver and other tissues, and is aggravated by
high carbohydrate food intake (resulting in chronic hyperglycaemia) and
obesity.
Prevention of Type 1 diabetes requires insulin injections. Type 2
diabetes can be prevented by eating small meals at a time, restricting
total carbohydrate intake, eating liberal amounts of fibre-containing
foods to minimize postprandial rise in blood glucose, consuming foods
with low glycemic index (legumes, unripe plantain), exercising regularly,
and if treated with insulin, synchronizing food intake with insulin action.
Delivering the Diabetes Association of Nigeria (DAN) Annual
Lecture on the theme “Diabetes Education and Prevention” in
collaboration with the College of Health Sciences and University of Port
th
Harcourt Teaching Hospital (UPTH) on Wednesday, 7 December, 2011
at the Conference Room of the Hospital, during the celebration of World
Diabetes Day, the National President of DAN, Dr. Sunny Chinenye
revealed that “a contributing factor to the epidemic of diabetes is
ignorance, which is due to lifestyle which is a factor because obesity is on
the increase, and the more obese we are, the more diabetic we become”
(Chinenye, 2011). To avoid being diabetic and obese, he advised that
people should monitor their blood glucose level regularly, be physically
active, avoid excessive intake of calories, reduce food intake when
confirmed over-weight as measured by body mass index of 25.0-29.9
2
kg/m , consume balanced diet – a little carbohydrate, some protein,
herbs, vitamins and minerals in every meal.
Presenting a paper earlier titled “What can I do to prevent
diabetes mellitus?” the Guest Lecturer Dr. Olubi Adesina (Consultant at

48
the Federal Medical Centre, Abeokuta) advised early diagnosis, regular
testing of blood sugar to reduce the risk of long term complications from
diabetes (Adesina, 2011). According to him, anyone can come down with
diabetes pointing out that high risk of diabetes includes one’s race which
is common among blacks; listing age, ethnic group, heredity,
hypertension, sedentary lifestyle and obesity as risk factors. Adesina
(2011) outlined signs of diabetes as fatigue, slow healing of wound,
impaired vision, skin infection, itching sensation, infertility and
miscarriages in women, increased thirst, unusual weight loss, stroke and
poor sexual performance; stating that for prevention, patients should
exercise regularly to burn enough calories, maintain a healthy weight,
consume a healthy diet with lots of vegetables, fruits and take a lot of
water instead of sweet drinks.

In people with Type 1

diabetes, the pancreas
cannot make insulin. They
often present with unusual
weight losses.

Source:http://www.medicinen
et.com/type_1_diabetes_pictur
es_slideshow/article.htm

Plate 8a. Cases of diabetes

Foot ulcers. A=leg, B=toe. In Type
2 diabetes, cuts or sores that are
slow to heal.
Sources: A:http://dermnetnz.org/site-
age-specific/img/ulcer-ven1-s.jpg
B:http://www.woundcarespray.com/wpc
ontent/uploads/2010/04/diabetic_foot_ul
cer_before.jpg

A B

Plate 8b. Cases of diabetes

x) Night blindness: (Nyctalopia) is a disorder caused by low
dietary intake of vitamin A. Vitamin A helps one to adapt to dim
light in man thereby increasing visual sharpness because in the

49
 presence of vitamin A, rhodopsin (the light-sensitive pigment in
the rod cells of the retina) is formed. In vitamin A deficiency,
there is (i) hyperkeratosis (excessive deposition of keratin of the
epithelium of the eye cornea leading to eye irritation and dryness
of the eye cornea resulting in blindness) (ii) Reproductive failure
in male rats and foetal resorption in females (iii) Poor resistance
to infection and stunted growth. Food sources are red palm oil,
whole milk, butter fat, egg yolk fat, liver, fish, cod liver oil,
tomatoes, pumpkin, spinach, paw-paw, carrots, peas, β-carotene
which the body converts to retinol (vitamin A1).
xi) Rickets and Osteomalacia: This is caused by the deficiency of
vitamin D (calciferol) in diets consumed. Vitamin D increases
the absorption of calcium and phosphorous from the intestine,
and helps to transport intestinal calcium and phosphorous to
parts of the body where they are used to build up strong teeth
and bones. Vitamin D prevents rickets and osteomalacia,
enhances normal growth, is needed for normal bone formation
by increasing mineral uptake by the bone (mineralization).
In vitamin D deficiency (i) bones are not well formed and are softened
(poor development of bones) due to poor calcium absorption and
incorporation into bone tissues – a condition called rickets in children
and osteomalacia in adults. (ii) Capillaries and bone-forming cells
(osteoblasts) are not formed (iii) there is resorption of bone minerals (Ca
and P), enlargement of wrists, knee, ankle joints, bowed legs and delay in
teeth eruption in infants.

Rickets
Source:http://www.thachers.org/images/
50 Rickets_family_1.jpg
 Plate 9. Rickets in children and osteomalacia in adults. (Vitamin D deficiency) shown by poor
development of bones.

Osteoporosis is characterized by low bone mass and structural

deterioration. Normal homeostatic bone remodeling is altered –
the rate of bone resorption is greater than the rate of bone
formation
Source:http://www.austincc.edu/nursmods/evc/evc_lev3/rnsg_1
247/musculoskeletal/documents/OsteomalaciaOsteoporosis.ppt

To prevent rickets/osteomalacia, eat food sources for vitamin D3

(cholecalciferol) such as fish and cod liver oil, cheese, egg yolk, milk,
butter and liver. Obtain vitamin D2 (ergocalciferol) by irradiation of
sterols in vegetables and grains (ergosterol) using UV light.

xii) Red Blood Cell Hemolysis: This is due to deficiency of vitamin

E (α-tocopherol). There is no true disorder in humans due to
daily dietary intake of vitamin E sources. In male rats and
rabbits, deficiency causes nutritional muscular dystrophy
(wasting of muscle fibres) and liver necrosis. In female rats, there
is resorption of the foetus 9-12 days after conception. The
tocopherols are good antioxidants and prevent oxidation of
unsaturated fatty acids (oleic, linoleic, linolenic and arachidonic
acids), protect vitamin A in foods from undergoing oxidation and
enhance growth in rats. Unlike synthetic antioxidants butylated
hydroxy anisole (BHA) and butylated hydroxytoluene (BHT), α-
tocopherol is a natural antioxidant which prevents fats and oils
from undergoing rancid. Vitamin E functions in reproduction
and its administration during early gestation results in the birth
of normal young. Plant food sources that prevent disorder are
cereals (wheat germ, rice, maize), legumes (soy bean, African
yam bean, cowpea), vegetable oils from (coconut, palm,
groundnut, castor seed, fluted pumkin). Animal sources include
liver, fish oils, butter, milk, egg.
xiii) Hemorrhage: This is caused by low dietary intake of vitamin K
or its deficiency in diet, and occurs mainly in chicks and birds.
Vitamin K1, K2 and K3 are phylloquinone, menaquinone and
menadione respectively. Hemorrhage is characterized by internal
bleeding which may lead to death, delayed blood clotting time
such that the removal of a few feathers from vitamin K deficient

51
 chicks may cause them to bleed to death. Deficiency of vitamin K
may also be due to prolonged intake of antibiotics that inhibit
the growth of gut or intestinal bacteria that synthesize vitamin K
to make its deficiency in humans and rats rare. In hemorrhage,
there is decrease in the production of blood coagulation factors.
Animal sources of vitamin K include fish meal, pig liver, cow
milk, egg yolk while plant sources include alfalfa and cereals.
Vitamin K is involved in liver synthesis of blood coagulation
factors which prevent hemorrhage. Vitamin K reverses the action
of anticoagulants such as dicoumarol and warfarin sodium
(vitamin K antagonists which in animals produce
hypoprothrombinemia) which prevent the normal functioning of
vitamin K in the liver synthesis of prothrombin.
xiv) Beriberi: This may be dry/wet/infantile and is due to dietary
deficiency in man of vitamin B1 (Thiamine) and high
carbohydrate intake in which only about 0.10-0.16 mg vitamin B1
is supplied daily. In animals, beriberi is known as polyneuritis. In
thiamine deficiency, there is impaired carbohydrate metabolism.
Symptoms characteristic of beriberi are headache, muscle ache,
constipation, anorexia (loss of appetite), loss of weight, tiredness,
general body weakness (fatigue), degeneration of the blood
pumping capacity of the heart, nausea, gastrointestinal upset and
vomiting. Vitamin B1 abolishes the symptoms of beriberi
resulting in the normal functioning of the body. In the form of
its coenzyme thiaminepyrophosphate (TPP), thiamine functions
in carbohydrate metabolism.

52
 Plate 10. Patients suffering from Beriberi (vitamin B1 deficiency).
Source: http://brain.otremba.org/images/beriberi1.jpg

Beriberi can be reversed by dietary intake of vitamin B 1 containing plant

foods such as soy beans, orange juice, rice polishings, whole wheat bread
flour, peanuts, potatoes and white/brown rice. Animal food sources of
vitamin B1 are cow milk, organs of beef and pork, cheese and eggs.
xiv) Abnormal external (ectodermal) maintenance of tissues:
This results from deficiency of vitamin B2 (Riboflavin), and is
characterized by glossitis (inflammation of the tongue making its
colour that of magenta), angular stomatitis (lesions of the lips
and mouth) and scrotal and nose dermatitis in man. Vitamin B 2
promotes growth in man and animals; helps in keeping the lips,
eyes, mouth and skin healthy; activates vitamin B 6 to convert
tryptophan to niacin and helps in energy release in the cell
because it is a component of flavinmononucleotide (FMN) and
+
flavinadenine dinucleotide, FAD (prosthetic groups of enzymes
that are hydrogen transport carriers). The nutritional disorder
can be prevented by intake of milk, liver, kidney, meat, eggs,
yeast, polished rice, muscle, potatoes and wheat germ.
xv) Pellagra (Rough skin): This nutritional disorder in humans is
caused by lack of vitamin B3 (Niacin) in diets. Pellagra is
characterized by diarrhoea, discolouration and scaling of the
skin (dermatitis), pigmentation, dementia (disorder of the brain
and nervous lesions). In dogs, deficiency results in black tongue
syndrome which characteristics are similar to human pellagra.
Niacin protects against pellagra in humans and black tongue in
+ +
dogs and via its coenzyme forms (NAD , NADP ), helps in
energy generation in intermediary metabolism. Pellagra, which is
common among humans who feed on maize or corn-based diets
can be prevented or treated by intake of protein rich in the
essential amino acid tryptophan which concentration is low in
corn. Food sources that contain niacin that can be eaten to
abolish pellagra are fresh fish, egg, milk, lean meat, crustaceae,
organs (liver, heart, kidneys) as well as rice polishings, whole
grains, legume seeds, green leafy vegetables and fruits.

53
 A B C

Plate 11. Patients suffering from Pellagra (Rough skin or vitamin B3 deficiency).
Sources: A&B:www.medicalook.com/Nutritional_supplement/Pellagra.html.
C:http://www.nutriweb.org.br/n0201/pelagra.gif

xvi) Poor Conditional Reflex: This occurs in man and dogs due to
lack of vitamin B5 (Panthothenic acid) in the diet. However, in
man this disorder is rare because vitamin B 5 is widely distributed
in plant and animal foods. In rats, there is poor growth and
inability of implantation to occur (reproductive failure). In dogs,
there is loss of conditional reflex, hypoglycemia, respiratory
problems leading to convulsion, coma and eventual death.
Vitamin B5 helps to maintain normal conditional reflex thus
ensuring good mental health. Excellent food sources among
others are yeast, liver, eggs, skim milk, sweet potatoes, meat,
fruits and vegetables.
xvii) Variable Nutritional Specie-dependent Disorders: This is
caused by deficiency of vitamin B6 (pyridoxine). In man, disorder
is rare but in infants there is convulsion due to loss of the
vitamin of infant formula during processing. In rats, there is
dermatitis, oedema, convulsion and abnormal growth.
Deficiency results in anaemia in dogs and dermatitis especially in
new world monkeys. Vitamin B6 prevents microcytic
hypochromic anaemia and dermatitis and in infants, protects
against convulsive seizures and promotes growth. Food sources
that prevent the disorder include rice bran or polishings, yeast,
egg yolk, liver, vegetables, whole grains, meat and kidney.
xviii) Pernicious Anaemia: In humans, dietary deficiency of vitamin
B12 (cyanocobalamine) is rare, but individuals consuming diets

54
 that lack this vitamin and animal products develop pernicious
anaemia which is characterized by decreased red blood cells,
impairment of nervous system and poor gastric secretion. In rats
and chicken, deficiency of vitamin B12 results in poor growth and
eventual death. Vitamin B12 is required for normal growth and
protects against pernicious anaemia since it aids the formation of
mature red blood cells. Animal food sources that prevent
pernicious anaemia include liver, kidney and fish. Plant foods
lack vitamin B12.
xix) Scurvy: This nutritional disorder is due to lack of vitamin C
(Ascorbic acid) in diets consumed by man, guinea pigs and other
primates. Scurvy is characterized by the rupture of blood
capillaries, hemorrhage, oedema, inability of collagen to form
and wounds to heal, loss of weight, bleeding and inflammation
of the gums, painful swelling of the joints and low blood tension
as well as poor tooth development. There is failure of osteoblasts
of the bone to form osteoid needed for the deposition of bone
salts to prevent the formation of weak bone that fractures easily.
Scurvy can be prevented by intake of foods containing ascorbic
acid such as tomatoes, potatoes, spinach, beans, mango, fresh
green pepper, guava, juices of citrus fruits (oranges, limes,
lemons). Note: Animal products contain little amount of
ascorbic acid due to losses during heat processing.

Scorbutic gums (Gingival Periungual hemorrhage Corkscrew hairs

haemorrhage) Source:http://www.nlm.nih.gov/medl Source:http://www.nlm.nih.gov/m
Source:http://www.monzy.com/s ineplus/ency/imagepages/2344.htm edlineplus/ency/imagepages/3036.
curvy/
htm

55
Plate 12. Patients suffering from scurvy (vitamin C deficiency)

xx) Poor growth, dermatitis and muscle pains: These occur in

humans, rats, chickens and monkeys that consume diets
deficient in vitamin H (Biotin). In biotin deficiency, there is
weight loss, irritability, swollen mouth and hair loss in hamsters.
The practice of drinking raw egg should be discouraged because
it could result in severe biotin deficiency. Avidin in raw egg
white binds to biotin to form biotin-avidin complex making the
biotin unavailable for cell utilization. Prevention of the disorder
due to biotin deficiency can be achieved through dietary intake
of egg yolk, liver, kidney, yeast, milk, nuts, grains and vegetables.

An advantage in man is that bacteria in the large intestine synthesize

large amount of biotin thereby lowering dietary intake.

xxi) Macrocytic/Megaloblastic Anaemia: Deficiency in diet of folic

acid (folacin) causes the disorder. Folic acid was formerly called
vitamin M (a hematopoietic factor for monkeys), vitamin BC
(chick growth factor), vitamins B10 and B11 as well as factor R
(bacterial growth factor). The deficiency of folic acid results in
the formation of megaloblastic cells containing abnormal levels
of DNA, and which in the bone marrow, matures leading to
anaemia due to decrease in red blood cell synthesis.

Folic acid is involved in normal red blood cell formation and prevents
anaemia. Food sources of folic acid are liver, kidney, fresh fish, yeast,
grains and green leafy vegetables.

Malnutrition
Malnutrition is a condition that develops when the body does not obtain
the right amount of nutrients. It refers to insufficient, excessive or
imbalance in the consumption of nutrients. People who suffer from
malnutrition are said to be malnourished. Malnourished individuals
consume enough calories, but not enough specific essential nutrients.
Poverty affects at least 1 billion people (16.7% of the world’s population)
and is the main cause of undernourishment and malnourishment.
Although poverty is a problem in developed nations, it is in the

56
developing countries of Asia, Africa and Latin America where hunger is
common, that you find the world’s most poorest people who do not own
land on which to grow food and have no money to purchase food.
st
According to the United States Report, as at 31 October, 2011, the world’s
th
population was 7.0 billion and Nigeria was ranked the 6 most populous
nation with a population of 167 million people. It was reported by the
th
Africa Independent Television News of Monday, 27 February, 2012 that
112 Million Nigerians are poor. Based on this report, 67.1% Nigerians are
poor.
In developed nations (Europe, North and South America),
malnutritional disorders are most often associated with nutritional
imbalances or excessive consumption rather than insufficiency of
nutrients in diets. Corn provides carbohydrate and protein and this does
not mean that a diet heavy in corn is a healthy one, because corn lacks
two essential amino acids, lysine and tryptophan required for normal
growth and development. Quantity of food refers to producing enough
calories while quality involves producing food with the appropriate
nutrients. Malnutrition occurs in people who are either undernourished
or overnourished.

Some Terminologies Associated with Malnutrition

i) Undernourishment: This results from consuming too few
essential nutrients or using/excreting them more rapidly than
they can be replaced, bringing about nutrient deficiency
disorders such as kwashiorkor, marasmus, avitaminosis and
mineral deficiency diseases. Underconsumption refers to the
long term consumption of insufficient sustenance in relation to
the energy that an organism expends, resulting in poor health. In
developing nations, you mainly find individuals who consume
fewer calories in their diets than they need, and are hence said to
be undernourished.
The main cause of undernourishment and malnourishment
which affects at least one billion people in the world is poverty.
In 2008, the Food and Agriculture Organization (FAO) of the
United Nations estimated that 850 million people (about 13% of
the world’s population) suffer from undernutrition.

57
ii) Overnourishment: Overnutrition or overnourishment is the
most prevalent form of malnutrition in America, and results
from eating too much of wrong foods. Over consumption is the
long term eating of excess sustenance in relation to the energy
that an organism expends, leading to poor health, as in obesity in
humans. Overnourishment is the main nutritional problem not
only in America but in other developed nations. In these nations
you mainly find people who consume food in excess of their
nutrient requirements and are said to be overnourished. They
also consume diets high in carbohydrate, fats and salt.
Foods that result in overnourishment include junk foods
found in fast food restaurants especially those containing white
sugar and many nutrients and not taking enough exercise. Junk
food is a slang name for food item which is low in, or contain
limited nutritional value. It includes foods high in salts, fats,
sugars, additives and calories, and low in nutrient composition.
Acute overeating is a symptom of eating disorder.
An excess intake of fat-soluble vitamins A and D for example
could be toxic. The junk foods are presented by the
manufacturers in such a way as to maximize taste and flavour
and minimize nutritional value and this results in “empty
calories”. Like white sugar, the process of refining white flour
used to produce white bread causes the leaching out of most of
the nutrients, that it is possible to have “zero fat” cookies
sweetened with white sugar which turns to fat as soon as the
body digests it (Anderson and Barbara, 1995;
<http://www.nutrition.gov/>
iii) Balanced and Unbalanced Diet: A balanced diet is one which
contains all the essential nutrients in required proportion with
water and roughage.A diet is said to be unbalanced when too
much of one or more nutrient(s) is/are present in the diet to the
exclusion of the appropriate amount of other nutrients.
iv) Clinical Nutrition: This deals with the application of nutrition
in health and disease. It is the nutrition and management of in-
patients in hospitals and out-patients at clinics. Clinical nutrition
incorporates the scientific fields of both nutrition and dietetics

58
 that aim to keep in patients, a balance in energy as well as
providing a balanced amount of nutrients in the diets consumed
by the patients.
In methods of clinical nutrition, the preferred route of
administration is oral intake of diets. Alternative methods
include enteral administration in nasogastric feeding and
intravenous administration in parenteral nutrition.
v) Clinical Malnutrition: This refers to insufficient, excessive or
imbalanced consumption of nutrients by in-patients in hospitals
and out-patients at clinics. Clinical malnutrition may be caused
by diseases, injuries and/or aging and by difficulties with the
ingestion of food such as dementia (loss of memory), stroke,
depression and dysphagia. These may be worsened by iatrogenic
factors or inability of the health care entity to compensate for the
aetiology of malnutrition. Many nutritional disorders/diseases
require clinical nutritional approach in their management. These
disorders (kwashiorkor, goiter, obesity, marasmus, beriberi,
scurvy, rickets) may have arisen either as a result of starvation,
undernutrition, overnutrition and nutrient deficiency. Criteria
for the classification of clinical malnutrition are embodied in
Table 6 below.

Table 6: Classification of Clinical Malnutrition

Patients Criteria for Clinical Malnutrition
2
(a) Moderately (i) Body mass index of 20.1-22.0kg/m
undernourished (any of the (ii) 5-10% unintentional weight loss in the past six
two criteria) months.

2
(b) Severely (i) Body mass index less than or equal to 20kg/m
undernourished (any of the (ii) Greater than or equal to 5% unintentional
three criteria) weight loss in the past one month.
(iii) Greater than or equal to 10% unintentional
weight loss in the past six months.
Source: Kruizenga et al. (2010).

59
Nutritional Disorders due to Mineral Deficiency
Minerals are inorganic substances originating from rocks and ores which
enter the food chain through the soil. There are 18 mineral nutrient
elements which are classified as major or minor (trace) elements. The
major minerals are calcium, phosphorous, sodium, chlorine, magnesium,
potassium and sulphur. The minor ones are cobalt, copper, fluorine,
iodine, manganese, molybdenum, selenium, zinc, chromium and nickel.
These minerals function generally as components of the skeleton, in
protein synthesis, oxygen transport, fluid and acid base balance in the
body as electrolytes and as metal cofactors in enzyme reactions. Both
deficiencies and excesses of these minerals can lead to diseases or
nutritional disorders. Humans obtain minerals by eating plants grown on
mineral-rich soils or by consuming animals that have fed on these plants.
Some of these disorders are
(i) Rickets and osteoporosis: This is due to calcium defiency in
diets. Long term calcium deficiency leads to rickets, and in
menopausal women, it can lead to osteoporosis in which the
bone deteriorates resulting in increased risk of fractures. Trace
amounts of calcium are essential to blood clotting, intracellular
signaling and muscle contraction. Large amounts are required in
stronger, dense bone and teeth formation and in the diet
especially during infancy, childhood and pregnancy.
Over retention of calcium or high calcium intake or
absorption causes hypercalcaemia (elevated level of calcium in
the blood), development of kidney stones, impaired kidney
function, nausea, vomiting, constipation and increased
urination. Food sources to prevent deficiency are vegetables,
fruits.
(ii) Iron Deficiency Anaemia (IDA): This is due to inadequate iron
intake in foods consumed. The groups most prone to the disease
are infants, children, pre-menopausal women or women of child-
bearing age. Iron is a component of haemoglobin, cytochrome
and myoglobin. As haemoglobin, iron carries oxygen from the
lungs to the tissues. Lack of sufficient iron in blood is a reason
that some people cannot donate blood. Symptoms of IDA are
fatigue, hair loss, weakness, irritability and brittle or grooved

60
 nails. This IDA (severe lack of iron stores in the body resulting in
low haemoglobin concentration) is the most widespread
micronutrient deficiency affecting human health and well-being,
work capacity and reproductive performance of individuals.
Excess iron or iron overload disorder is a disease caused by
over-accumulation of iron in the body which affects the heart,
liver and endocrine glands. IDA can be prevented by adequate
intake of iron from the diets consumed. Food sources of iron
include red meat, poultry, insects, beans, fortified bread,
breakfast cereals and leafy vegetables.
(iii) Keshan Disease: This is caused by selenium deficiency, and also
occurs in people who consume foods grown from selenium
deficient soils.
(iv) Growth Retardation: This is due to deficiency of zinc in diets.
In children, there is also impotence and delayed sexual
maturation, diarrhoea, susceptibility to infection and death.
Deficiency may be due to low dietary intake, malabsorption,
chronic kidney and liver diseases, diabetes, sickle cell disease,
eye and skin lesions and poor appetite. Food sources of zinc that
prevent zinc disorder are soy foods, cooked dried beans, nuts,
fortified cereals, peas and seeds.
(v) Hypertension: This is caused by lack of magnesium in diets.
Excess magnesium causes weakness, nausea, vomiting, impaired
breathing and hypotension. Note that calcium, magnesium and
phosphorous are the major constituents of bones. Food sources
of magnesium include fruits, nuts and vegetables.
(vi) Hyponatremia: This is low level of sodium in blood caused by
inadequate sodium in diets consumed. Excessive sodium intake
causes hypernatremia and hypertension. Excess water intake
without replenishment of sodium and potassium salts also
causes hyponatremia which can lead to water intoxication.
(vii) Hypokalemia: This is low level of potassium in blood due to
deficiency of the mineral in foods consumed. Excess potassium
in diets causes hyperkalemia and palpitations. Both potassium
and sodium control water balance in the body.

61
Toxicology
Toxicology is a branch of medical science that deals with the type,
nature, reactions and effects of toxins or poisons. In the biomedical
sciences, toxicology deals with the adverse effects in humans resulting
from exposure to drugs and other chemical substances. Human beings
live in environments where hundreds of chemicals abound, and they
ingest, inhale or absorb a number of these chemicals. Monosson (2006)
defined toxicology as the dynamic interaction of chemicals with living
systems. Toxicologists investigate how chemicals interact with biological
systems by focusing on the adverse effects and outcomes caused by such
interactions (http://www.eoearth.org/article/toxicology).
Historically, toxicology began with the early cave dwellers who
recognized poisonous plants and animals and used their extracts for
hunting or in warfare, and by 1500 B.C, written evidence showed that
hemlock, opium, arrow poisons and certain metals were used to poison
enemies or for state executions. By 1500 AD, Paracelsus determined that
specific chemicals were actually responsible for the toxicity of a plant or
animal poison, and stated that the response of the body to those
chemicals depended on the dose received. From his studies, it was
evident that small doses of a substance might be harmless whereas large
doses could be toxic, and this is presently known as the “dose-response
relationship” which is a major concept of toxicology. Vice-Chancellor Sir,
Paracelsus is often quoted for his statement that “All substances are
poisons; there is none which is not a poison. The right dose differentiates
a poison and a remedy” I agree with this statement because people have
even died of water intoxication.
A Spanish physician, Orfila is often referred to as the founder of
toxicology because he was the first to establish a systematic correlation
between the chemical and biological properties of poisons of the time. By
1800 AD, he demonstrated effects of poisons on specific organs by
analyzing autopsy materials for poisons and their associated tissue
damage.
th
By the 20 century, the knowledge of toxicology and toxic effects
of chemical agents on organs and cells had advanced with the discovery
of the molecule of life, DNA, and is now being revealed at the molecular

62
level with virtually all toxic effects caused by changes in biochemicals
and specific cellular molecules (Monoson, 2006).

Some Branches of Toxicology

Toxicology is a broad discipline that cannot solely be dealt with in this
lecture, and hence a few branches and terminologies used are stated
based on current knowledge and reports by Monosson (2006) and Plaa
(2007).
(a) Environmental Toxicology: This deals with the adverse effects
of chemicals present as pollutants of the air, water and soil to
biological systems. Biologic targets to these pollutants are
human beings, terrestrial and aquatic lives. The Food and
Agriculture Organization of the World Health Organization
(FAO/WHO) Joint Expert Commission on Food Additives has
adopted the term “acceptable daily intake (ADI)” to denote the
daily intake of a chemical which, during an entire lifetime,
appears to be without appreciable risk.
(b) Ecotoxicology: This deals with the impact and toxic effects of
chemical and physical agents on the populations and
communities of living organisms within an ecosystem.
Ecotoxicology differs from environmental toxicology in that an
environmental process may exert severe effects on individual
organisms, without having important impact on populations or
on an ecosystem.
(c) Occupational Toxicology: This branch of toxicology deals with
the study on chemicals found in a work place. The task of an
occupational toxicologist is to identify the chemical agents,
define the conditions for their safe use and prevent the
absorption by the body of amounts that may cause harm. The
American Conference of Governmental Industrial Hygienists
periodically prepares lists of recommended threshold limit
values (TLVs) for about 600 such chemicals, and these guidelines
are re-evaluated as new information become available (Doull,
2001).
(d) In Vitro Toxicology: In vitro is “in glass or in the test tube” and
it is different from In vivo or in the cell”. This is the study of the

63
 effects of toxic chemical substances on cultured bacteria or
mammalian cells, and is employed primarily to identify
potentially hazardous chemicals and/or to confirm the lack of
certain toxic properties in the early stages of the development of
potentially new useful substances such as therapeutic drugs,
agricultural chemicals and direct food additives
(http://en.wikipedia.org/wiki/ Invitrotoxicology, 2011). The in
vitro toxicity testing can be a useful, time and cost-effective
supplement to toxicity studies in living animals, especially now
that animals cannot be used for laboratory experiments without
ethical clearance from the “Animal Rights Group”.
(e) Aquatic Toxicology: This is the study of the effects of
manufactured chemicals and other anthropogenic and natural
materials and activities on aquatic organisms at various
organizational levels from subcellular via individual organisms to
communities and ecosystems (Rand and Petrocelli, 1985). In
addition to analytical testing for known pollutants, aquatic,
whole effluent toxicity tests have been standardized and
performed routinely as a tool for evaluating the potential
harmful effects of effluents discharged into surface waters
(United States Environmental Protection Agency, Whole
Effluent Toxicity)
(http://www.epa.gov/waterscience/methods/wet)
(f) Food Toxicology: This is the study of the types, nature,
properties and effects of toxic substances found in natural or
synthetic association with food. Vice-Chancellor Sir, of the
different areas of toxicology explained so far, I wish to narrow
down this lecture to food toxicology which is part of my field of
specialization as a Nutritional Biochemist and Toxicologist.

Some Terminologies used in Toxicology

i) Toxicant: This is a chemical or physical substance that produces
adverse biological effects (acute or chronic) of any nature. It may
also be referred to as a xenobiotic or a chemical that is foreign to
living organisms. The location in the body where these chemicals
interact to cause adverse effects is known as the target tissue or

64
 the site of action. Toxicants may affect only specific tissues or
organs and not the whole body. These specific sites are known as
the target organs or target tissues.
ii) Toxin: A toxin is a specific protein produced by a living
organism such as plant or animal which exhibits immediate
effect on an organism. Examples are mushroom toxin, and
tetanus toxin. Organic toxins are large molecules which occur in
living organisms and can be synthesized as well as be obtained
from natural sources. Inorganic toxins are specific chemicals
(minerals) that are not obtained from living systems.
iii) Poison: This is a toxicant that causes immediate illness or death
when it is taken into the biological system in very small amount.
iv) Toxic Agent: This is any physical, chemical, or biological
substance that produces an adverse biological effect. Example of
a physical toxic agent is radiation; chemical toxic agent is
cyanide and biological toxic agent is snake venom.
v) Toxic Organisms: If an invading organism excretes chemicals
which is the basis for toxicity, the excreted substances are called
biological toxins and the organisms are referred to as toxic
organisms. Example is tetanus which is caused by a bacterium,
Clostridium tetani. The latter does not cause disease by invading
and destroying cells. It is the toxin (neurotoxin) excreted by the
bacterium that travels to the nervous system that produces the
disease.
vi) Toxic Substance: A toxic substance is a material which has toxic
properties and even in low concentrations, results in abnormal
metabolism in the organ such as the liver. It may be a discrete
toxic chemical or a mixture of toxic chemicals, for e.g. lead
chromate, asbestos and gasoline are all toxic substances. Lead
chromate is a discrete toxic chemical. Asbestos is a toxic material
that does not consist of an exact chemical composition, but a
variety of minerals and fibers. Gasoline is a toxic substance
rather than a toxic chemical because it contains a mixture of
many chemicals. Toxic substances may not always have constant
composition, and the composition of gasoline for example varies
with the octane level, manufacturer and season

65
 (http://www.eoearth.org/article/ toxicology). A toxic substance
may be a systemic toxicant or organ toxicant. A systemic
toxicant is one that affects the entire body or many organs rather
than a specific site. For example, potassium cyanide (KCN) is a
systemic toxicant because it affects virtually every cell and organ
in the body by interfering with the ability of the cell to utilize
oxygen.
vii) Potency of a Chemical: The potency of a chemical or its level of
toxicity depends on its movement through the body to the target
tissue (toxicokinetics), its ability to interact with the body to
cause harm (toxicodynamics), and the dose the body receives
(level of exposure). The concentration of a chemical that reaches
the target tissue is a function of its kinetics, dynamics and
exposure level and both the kinetics and dynamics depend upon
the current biochemical status (enzyme concentration during
the time of exposure and nutritional status) of the living
organism.
viii) Median Lethal Dose: This is the dose of a chemical or drug
required to kill 50% of the experimental animals or test
population. It is denoted by LD50 defined over a period of time.
These studies are called lethality studies and the most common
LD50 test is the acute toxicity test. Here, experimental animals
(rats) are given a single dose of a chemical and the LD50 is
determined over a 24 hour period of time. Lethality test is used
to provide insight into the relative potency of new chemicals
(http://www.eoearth.org/ article/toxicology).
ix) Hazard: This is the ability of a chemical agent to cause injury or
harm in a given situation. In order to assess hazard, the
knowledge of the toxic effect of the hazardous substance and the
concentration to which individuals are liable to be exposed is
important.
x) Risk: This is the expected number of times (frequency) of
occurrence of undesirable effect due to exposure to a chemical or
physical agent. Dose-response data are used in the estimation of
risk.

66
xi) Route of Exposure: Inhalation is the major route of entry of
chemicals and atmospheric pollutants such as gases (SO 2, H2S)
into the body. There is also oral ingestion which is a minor route.
For soil and water pollutants (e.g. heavy metals), the major route
of exposure for human beings is oral ingestion.
xii) Time of Exposure: Toxic reactions differ based on the duration
of exposure. Time of exposure is the duration of exposure of a
test organism to a test solution. Single or multiple exposures that
occur(s) over 24 or 48 hours denote acute exposure resulting in
acute toxicity while multiple exposures occurring over a longer
period of time represent a chronic exposure that brings about
chronic toxicity.

Toxicity: This is the ability of a text substance (poison, toxicant) to cause

adverse and undesirable effect on living systems. Toxicity is a function of
the dose administered, the exposure concentration and duration of
exposure.

Dose: This is the amount of a toxicant or poison or chemical agent that

an organism receives into its system.

Lethal Concentration: This is the concentration of a toxic factor that

causes death in a specified proportion of test organisms and is usually
expressed as LC. LC50 is the concentration that kills 50% of exposed
organisms at a specific time of observation, say 96 hours.

Inhibiting Concentration: This is toxicant concentration that impairs

the activity of a biosystem. It is represented by IC such that IC75 is the
concentration that will, for example, cause 75% impairment in the
growth of fish relative to control.

Effective Concentration: This is denoted as EC and is the concentration

of a toxicant estimated to cause a known sublethal effect in a given
proportion of test organisms under a specified time such as 48 or 96 hr. A
48-hour EC25 is the effective concentration for 25% of the test organism
in 48 hour for a change in biological activity. The sublethal effect may be
loss of balance or change in respiration.

67
Toxicants in Natural Association with Foods

Natural Toxicants in Foods: These are called biological toxicants or

endogenous dietary toxins found naturally in plant foods which interfere
with the processes of living cells and tissues. They are also known as
antinutritional factors. It has been reported that a major factor that limits
the wider use of tropical plant foods is the widespread occurrence in
them of a diverse range of natural compounds capable of precipitating
deleterious effects in man and animals, and manifestations of toxicity
range from severe reduction in food intake and nutrient utilization to
profound neurological effects and even death (Osagie, 1998).
The toxic factors are widely distributed in the plant kingdom and
in all parts of the plant, but the seed contains the highest concentration
of the toxicants. The toxicants are found in roots and tubers, cereal
grains, leafy vegetables, nuts and seeds and fruits with a more complex
array of these antinutritional factors found in tropical legumes than any
other species of crops.
Osagie (1998) reported that knowledge of toxic substances
present in plant foods are useful in that (i) the toxicants are recognized
as components of diet of humans and domestic animals and affect the
overall nutritional value of foods (ii) it helps dieticians to avoid
recommending foods that their patients cannot tolerate possibly because
of inability to metabolize or detoxify certain substances therein (iii)
amounts of certain substances that are relatively safe when consumed
alone can sometimes, when taken together, have serious and even fatal
effect e.g. tannins in a protein-marginal diet (iv) food regulatory bodies
and public health authorities need to be informed about possible dangers
related to widespread, long standing practice previously regarded as safe.
For example, cassava has been consumed in the tropics for a long time
without apparent consideration for the high cyanide content.

NATURAL TOXICANTS, THEIR DISTRIBUTION IN PLANTS AND

PHYSIOLOGICAL EFFECT
1. Protease inhibitors: These are toxic proteins which constitute
the most potent inhibitors and the most studied toxicants in
plant foods. Examples are (i) trypsin inhibitors in legumes

68
 (cowpea, groundnuts, African yam bean, bambara groundnut)
and in eggs. (ii) Chymotrypsin inhibitor in potatoes (iii) Papain
inhibitor in soybean, broad bean and egg white (iv) Elastase
inhibitor in kidney bean (v) amylase inhibitor in wheat, mangoes
and banana. These inhibitors have growth depressing effect in
rats, mice and humans. Mechanisms of action of protease
inhibitors is that of their ability to form stable complexes with
the enzyme; the irreversible complexes undergo many types of
enzyme-substrate complex interactions that bind the protein,
making it unavailable for digestion to release the constituent
amino acids of protein required for growth. For example,

Trypsin + trypsin inhibitor  Trypsin-trypsin inhibitor complex

Protein
Trypsin – trypsin inhibitor – protein – complex.

The presence of protease inhibitors in foods that we consume

result in pancreatic hypertrophy (enlargement) and hyperplasia.

2. Lectins: These are toxic proteins that can bind specific sugars or
glycoproteins – a reaction shown in vitro by the clumping or
agglutination of erythrocytes (red blood cells) from various
animal species, for which reason, they are also known as
haemagglutinins. Lectins are found highest in cowpea (Vigna
unguiculata) (2.17g/kg) followed by pigeon pea (Cajanus cajan)
(1.28g/kg) and then soybean (Glycine max) (0.95g/kg) as reported
(Ikegwuonu and Bassir, 1976a). Lectins also occur in lima beans
(Phaseolus lunatus).

Physiological effects of lectins include:

(i) They cause the clumping of red blood cells.
(ii) They bind to the epithelial cells lining the small intestine
resulting in severe growth depression and death.
(iii) Their toxicity stem from the production of intestinal
lesions and histopathological changes in organs (liver,
lungs, kidney and heart).

69
 (iv) Oedema and fatty infiltration of the liver.

3. Cyanogenic glycosides: These are compounds which on

hydrolysis by an enzyme or acid, produce toxic hydrogen
cyanide. They include linamarin, lotaustralin and amygdalin.
Linamarin (95%) and lotaustralin (5%) occur mainly in bitter
cassava roots and leaves and not the sweet cassava. They occur in
legume seeds (soybean, cowpea, African yam bean etc), yams,
sorghum, sweet potatoes, lettuce and peas, while amygdalin
occurs in almond, pear and the apples. In terms of chemical
structure for linamarin and lotaustralin in particular, one of the
methyl groups (–CH3) in linamarin is replaced by an ethyl group
(– C2H5) to obtain lotaustralin. Hence;
(i) Hydrolysis of linamarin produces glucose, dimethyl ketone
and hydrogen cyanide (HCN).
(ii) Hydrolysis of lotaustralin produces glucose, ethylmethyl
ketone and HCN

CH2OH CH2OH
O C N O
H H O C CH3
acid pH 6.0 H H OH
Enzyme + CH2OCH3
OH H CH3 linamarase HO OH H
HO H H
+ HCN
H OH H OH
Linamarin Glucose

The consumption of foods containing cyanogens could cause

acute or chronic cyanide toxicity. Acute toxicity is fatal resulting
in a high rate of mortality and morbidity, while chronic toxicity
has been linked to goitre (Ekpechi, 1967) and tropical ataxic
neuropathy (Osuntokun, 1972) which is due to demyelination of
the nervous tissues. In the mitochondrial electron transport
chain, HCN, which is consumed as part of our diet inhibits the
enzyme, cytochrome C oxidase, thereby hindering the transport
of electrons to molecular oxygen to form water. The resultant
effect is respiratory failure and death.

70
4. Oligosaccharides: These are carbohydrates which contain three
to eight monosaccharide units linked together by glycosidic
bonds. They are widely distributed in legumes, roots and tubers.
Major producers of flatulence when these foods are eaten are
raffinose, starchyose and verbascose. Man and animals lack the
enzyme α-1,6-galactosidase in their intestinal mucosa, and hence
cannot digest these oligosaccharides . When the legume source
is not properly cooked and eaten, the raffinose oligosaccharides
are found undigested, pass into the wall where intestinal
bacterial fermentation occurs producing gases mainly hydrogen
and carbon(IV)oxide, and hence flatulence (Wagner et al., 1976;
Fleming, 1981). The reaction of these gases with water produces
acid resulting in stomach discomfort, but the acidity can be
neutralized by the intake of mist mag (magnesium trisilicate).
Flatulence is accompanied by frequent belching, abdominal
distention and pain, release of nauseating gas, diarrhoea and
weakness.
5. Dhurrin: This is a poisonous natural compound found in millet
and in the shoots, seeds and roots of sorghum and in local foods
and beverages produced from sprouted sorghum grains. Its
presence in these food materials detracts from their full
nutritional potentials.
6. Saponins: These are glycosides found in sugar cane, pea,
soybean and sugar beets, millet, bitter kola, mango, plantain,
walnut, cocoyam tuber, pigeon pea and lima bean with high
foaming capacity, and hence used to generate foam in beer. They
have bitter taste. Deleterious effects of saponins include their
hemolytic effect on red blood cells. They are cytotoxic and affect
intestinal permeability. However, the beneficial effect of saponin
is that it has cholesterol-lowering property (Oakenful and Sidhu,
1989). Since your life is in your hands, it will be your decision to
consume or desist from foods high in saponin content.
7. Favism: This is induced by glycosides found in faba beans. The
glycoside alters the membrane permeability of red blood cells
leading to rupturing tendencies and hemolytic anaemia found
associated with the favism-inducing glycosides.

71
8. Gossypol: It is a plant phenolic complex structure found in
cotton seed and cotton seed oil which is toxic to various animal
models. Symptoms of its toxicity include loss of body weight and
apetite, diarrhoea, hemolytic anaemia and impairment of blood
clotting mechanisms. Physiological effect is that it interferes
with the digestion of proteins.
9. Mycotoxins: These are toxic substances produced as fungal
metabolites. The search for environmental contaminants
responsible for the high cancer frequency in Nigeria had
inadvertently focused attention mainly on the presence of
mycotoxins (Bababunmi et al., 1977). Most studied mycotoxin is
aflatoxin which is produced by the fungus that belongs to the
Aspergillus species. Aflatoxins are designated AFB 1, AFB2, AFG1,
AFG2 to show their fluorescence in blue or green UV light.
Aspergillus species (which produce Aflatoxins) grow on foods
(rice, groundnuts, garri, beans, yams) containing major nutrients
and water. It also grows as mould on moist bread left for
sometime. The practice in the village whereby consumers use
knife to cut off the mould and eat the bread should be
discouraged, because what they are consuming is aflatoxin that
has permeated the entire loaf of bread. Aflatoxins are
hepatotoxic (toxic to the liver), carcinogenic, prolong blood
clotting time and produce osmotic swelling of the mitochondria
thereby affecting biochemical pathways that generate energy.

Plate 13. A man in a Nigerian village cutting off mould that has grown on a N250.00 loaf of
stale bread prior to consumption
72
10. Goitrogens: are toxins which cause goitre in animals and
humans by interfering with iodine utilization. They are usually
called glucosinolates, because on enzymatic
hydrolysis/breakdown, they produce glucose, a sulphur
containing group and isothiocyanate. The breakdown of
isothiocyanate produces the main toxic factor, hydrogen cyanide
(HCN). Goitrogens occur in vegetables, kale and cabbage.
11. Alkaloids: These are a class of basic, aromatic, nitrogen-
containing plant products which have complex structures and
possess significant pharmacological properties. They are found in
some species of bitter yam, kola nuts, Mucuna pruriens, cocoa
beans which contains the alkaloid theobromine, potato which
contains the steroidglyco alkaloid e.g. solanine that interferes
with transmission of nerve impulses and is hemolytically active
and toxic to humans causing neurological disorders and
gastrointestinal upsets. Examples of alkaloids are morphine,
cocaine, nicotine (a stimulant whose metabolite N-nitroso
nicotine is a potent carcinogen), indometacin, caffeine, heroin,
etc.

12. Oxalate: is a two-carbon dicarboxylic acid anion produced and

accumulated in crop plants as soluble salts of sodium, potassium
or ammonium oxalate. It also occurs as oxalic acid or as
insoluble calcium oxalate in vegetables (spinach) cocoa, tea,
yams, cocoyams, fruits, sweet potatoes. Oxalate interferes with
2+ 2+
mineral availability by binding to divalent cations (Ca , Mg ,
2+
Zn ) making them unavailable for cell utilization. Calcium
oxalate crystals in food crops cause acridity irritating to the
digestive tract when the foods are eaten. High concentration of
oxalate in the diets we consume can increase the risk of kidney
calcium absorption, resulting in renal calculus or kidney stone
and hence, oxalate poisoning.
13. Tannin: It is any polyphenolic compound having a molecular
weight greater than 500. There is hydrolysable tannins (those
that can be hydrolysed into carbohydrate mixture and phenols)

73
 and condensed tannins, which are complex polymers. Tannins
occur in root crops, legumes, cowpea, lima bean, pepper, fruits,
various yam species, sorghum, plantain, sweet potatoes, millet,
maize, breadfruit, star apple, raphia palm (peel and pulp).
Although tannins play a major role in the plant’s defense against
fungi and insects, they have the following deleterious effects as
reported (Butler, 1989).
(i) Tannins decrease protein quality by interfering with
protein digestibility and palatability.
They cause damage to the intestinal tract, and interfere with the
absorption of iron, and its toxicity may result in a carcinogenic
effect.
14. Phytate: Phytic acid is a hexaphosphate derivative of inositol
and is a form in which phosphorus is stored in plants. It is found
in tubers and roots, cereals, vegetables, most legumes such as
soya bean, then in palm kernel seed and cotton seed meal. It
forms insoluble salts with divalent metal ions (calcium,
magnesium, iron and zinc), and hence interferes with mineral
availability since it renders the minerals unavailable for
absorption into the body. Phytate also affects protein
digestibility by binding with proteolytic enzyme and forming a
chelate with divalent metals.
15. Other Toxicants: These include avidin in egg white which is a
biotin antagonist, and citral found in orange peel as a vitamin A
and C antagonist. In linseed meal is linetin which interferes with
vitamin B6 (pyridoxine) utilization. Lathyrus sativus used as
cattle feed and in making bread in the absence of wheat can
cause a neurological disease (lathyrism). Lathyrism is
characterized by a feeling of heaviness of the legs and weakness.
The disease is caused by the toxic agent (β-amino propionitrile)
in the seeds of Lathyrus sativus.

Environmental Toxicants/Contaminants in Foods

These are toxic factors found in the environment (air, water, soil) which
interact with the foods we consume. They include:

74
(i) Pesticides: They destroy pests such as mosquitoes, cockroaches
etc. Example is such as dichlorodiphenyltrichloroethane (DDT)
which is toxic to humans but mosquitoes can metabolize active
DDT to inactive compound that is not toxic to them.

Cl C Cl

Cl C Cl

Cl
Dichlorodiphenyltrichloroethane (DDT)
The organo phosphorus compound parathion (an insecticide) is
non-toxic, but insects (mosquitoes) metabolise it to the toxic
compound, paraoxon.
(ii) Herbicides are used to kill weeds, examples are 2, 4-
dichlorophenoxy acetic acid and 2,4,5-trichlorophenoxy acetic
acid, and in the process of using them, they get into foods and
are consumed by humans.
(iii) Rodenticides kill rodents. Example is α-naphthylthiourea which
is not toxic, but is metabolized to produce toxic hydrogen
sulphide that can poison the respiratory system.

Environmental Contaminants
These are chemicals found in the environment in which food is grown,
harvested, transported, stored, packaged, processed and consumed. The
physical contact of the food with its environment results in food
contamination. Possible sources of food contamination are:
(i) Soil which contains perchlorates, toxic heavy metals (cadmium,
nickel, mercury, arsenic etc).
(ii) Water due to the presence of mercury, arsenic etc.
(iii) Air which contains polycyclic aromatic hydrocarbons,
90 137
radionuclides such as Strontium and Caesium.
(iv) Processing and cooking equipment which are the sources of
copper, cleansing agents, lubricants, etc.
(v) In air, soil and water are polychlorinated biphenyls (PCB) and
polybrominated biphenyl ethers (PBBE) and dioxins.

75
(vi) Packing materials which contain tin, lead, antimony,
perfluorooctanoic acid as food contaminants.
(vii) Naturally-occurring toxins such as mushroom toxins, mycotoxins
(aflatoxins), shell fish toxins that cause shellfish poisoning,
alkaloids, phytolectins etc.

Food Contamination
This is the unintentional introduction or occurrence of a contaminant
(any biological, chemical or physical agent or substances foreign to food)
in food which may compromise food value, quality,safety and edibility.
The physical agent could be high dose irradiation. Contamination may
occur via environmental pollution as in the case of toxic metal
pollutants/toxicants or via the intentional use of agrochemicals such as
pesticides (insecticides, rodenticides, herbicides), plant growth
regulators (gibberellins, auxins, ethylene), fertilizers and veterinary drugs
(nitrofuran, chloramphenicol, fluoroquinolones and bovine
somatotropin). These contaminants in food can cause consumer
illness/adverse health effects. Apart from food, the contaminants enter
the body through the skin, eyes, lungs, and mouth where they are stored
in body fat and accumulate over time if the body cannot eliminate them.
The emerging food contaminants are those that have been found in foods
most recently, as compared to most contaminants that have been known
for many years. Examples of the emerging food contaminants are
perchlorate, perfluoro octanoic acid (PFOA), furan, acrylamide, benzene
and monochloro propane diol (MCPD).

Health Effects of Environmental Toxicants/ Contaminants in

Foods that we Consume
Dr. Joseph Mercola is a Leader in the United States Wellness Movement,
a New York Times best selling Author and founder of Mercola.com, the
second most visited non-governmental health website after web MD.
Below are the top ten most common environmental toxins that
are among the most prevalent in the air, water and/or food supply, their
sources and health effects, as reported (Mercola.com).

76
(i) Polychlorinated biphenyls (PCBs): These are environmental
organic pollutant found in farm-raised salmon fed meals of
ground-up fish that have absorbed PCBs in the environment.
PCBs cause cancer and impaired foetal brain development.
(ii) Pesticides: Pesticides are highly toxic and neurotoxic. The
sources are foods (fruits, vegetables, apple or its juice and
commercially raised meat) and bug sprays. According to the U.S.
Environmental Protection Agency (EPA), 60% of herbicides, 90%
of fungicides and 30% of insecticides are known to be
carcinogenic as they cause cancer. They also cause Parkinson’s
disease, birth defects, miscarriage, brain and nerve damage,
blocking the absorption of nutrients in foods.
(iii) Mould and other fungal toxins: Example is the mycotoxin/
fungal toxin such as aflatoxin. Sources are contaminated
buildings, foods like peanuts, wheat, corn and alcoholic
beverages. These food toxicants/contaminants cause cancer,
heart disease, asthma, multiple sclerosis, diabetes and allergic
reactions.
(iv) Phthalates: They are used to lengthen the life of fragrances and
soften plastics. The major sources are plastic wrap, plastic
bottles, plastic food storage containers – all of which leach
phthalates into the food we eat. They are dangerous to children
in particular by mimicking hormones and so, causes damage to
the endocrine system.
(v) Volatile organic compounds (VOCs): These are a major
contributing factor to ozone (O3), and are air pollutants. They
are present in many household products such as drinking water,
carpets, paints, deodorants, cosmetics, air freshners, cleaning
fluids, dry cleaned clothing and moth repellants. These get into
foods we eat, and health risks include cancer, eye and respiratory
track irritation, visual disorders, headache, dizziness and
memory impairment.
(vi) Dioxins: These compounds are formed from combustion
processes such as waste incineration and smoke from burning of
wood and coal. High concentrations of dioxins are found in
smoke due to fires from oil and gas explosion/flaring as in the

77
 th
16 January, 2012 Chevron gas explosion in Koluama I & II
Communities in Brass Local Government Area of Bayelsa State
that lasted 46 days before the fire was put off. Major sources are
all forms of animal fats. Over 95% of exposure to dioxins comes
from eating commercial animal fats. Health risks include cancer,
reproductive and developmental disorders, chloracne (a severe
skin disease with acne-like lesions), skin rashes and
discolouration, excessive body hair and mild liver damage.
(vii) Asbestos: These are insulating materials which when old and
crumbly, release fibres into the air. Sources are insulation on
floors, ceilings, water pipes and heating ducts. Health problems
include cancer, scarring of the lung tissue and mesothelioma (a
rare form of cancer).
(viii) Heavy metals: Arsenic, mercury, cadmium, lead and aluminium
are prevalent in the environment, and can accumulate in soft
tissues of the body. Major sources are drinking water, fish,
vaccines, pesticides, preserved wood, antiperspirant, building
materials, dental amalgams and chlorine plants. Heavy metals
cause cancer, neurological disorders, fatigue, nausea, vomiting,
decreased production of red and white blood cells, abnormal
heart rhythm (heart beat) and damage to blood vessels.
(ix) Chloroform: This colourless liquid has a pleasant non-irritating
odour and a slightly sweet taste and formed when chlorine is
added to water. Air, drinking water and food can contain
chloroform. Consumption of foods containing chloroform can
cause cancer, reproductive damage, birth defects, dizziness,
headache, fatigue as well as liver and kidney damage.
(x) Chlorine: This is a yellow-green highly toxic gas and one of the
most heavily used chemical agents obtained from household
cleaners, drinking water (in minute and physiologically tolerable
amounts), air when living near a paper plant that uses chlorine
in industrial processes. Chlorine causes sore throat, coughing,
eye and skin irritation, rapid/fast breathing, narrowing of the
bronchi, blue colouring of the skin, accumulation of fluids in the
lungs, pain in the lung region, severe eye and skin burns, lung
collapse and reactive air ways dysfunction syndrome (RADS) – a

78
 type of asthma (Mercola.com). The contaminant/toxicant levels
in foods are regulated by the EPA via a system of standards
called food tolerances, which is a legal limit that the
concentration of a toxicant/contaminant in a particular food
must not exceed.

Other Environmental Food Contaminants

(i) Banned Pesticides: These include lindane in tomatoes and the
highly toxic methamidophos in tangerines, grapes and straw
berries. In India, soft drinks were found contaminated with
banned pesticides such as lindane, DDT and malathion and in
China, powdered ginger had been contaminated with the banned
pesticide, aldicarb. News of formaldehyde found in Vietnamese
national dish (pho) as well as in fruits and vegetables broke in
2007 Vietman Food Scare. Formaldehyde is a carcinogen which
in water produces formalin used in the preservation of
anatomical specimens.
(ii) Hair in Food: Waxes and other hair products are contaminants
on the hair that cause choking and repulsion – induced
vomiting. Hair is not easily digestible and in the United
Kingdom, it breaks the regulations of the U.K Food Safety Act of
1990 to serve people food which contains hair in restaurants
(Valdes-Biles and Ziobro, 2007). To prepare or serve food, one
should wear complete capture hairnets and people working in
the food industry are required to cover their hair.
(iii) Unavoidable processing contaminants: They are formed by
chemical reactions of food constituents during processing and
include trans fat, benzene, acrylamide, polycyclic aromatic
hydrocarbons, histamines and nitrosamines.

Most environmental food toxicants and contaminants have been

implicated in cancer. What is then carcinogenesis and by what
mechanism does it occur?

79
Carcinogenesis
The induction of cancer in an organism is termed carcinogenesis. In this
process, a normal cell is transformed into a cancer cell by a cancer-
causing agent or carcinogen. Carcinogenic polycyclic aromatic
hydrocarbons (PAHs) have been identified in urban air (Morlin et al.,
1979). The carcinogenic PAH had earlier been detected in smoke,
particularly of cigarette, and the unavoidable conclusion reached after a
twenty-year study of mortality in relation to smoking was that cigarette
smoking was a direct cause of cancer of the lungs, oesophagus and
respiratory site tumors (Hoffman and Wynder, 1972).

Mechanism of Carcinogenesis
metabolic specific
Chemical carcinogen activation Ultimate receptor Altered
(procarcinogen) carcinogen (DNA) receptor
expression
growth
progression and
Independent Differentiated Latent tumour cell
development
undifferentiated tumour
cancer

Hence, the first steps of chemical carcinogenesis involving metabolic

activation of procarcinogen and the reaction of resulting ultimate
carcinogen with specific cellular receptor (DNA) to form altered receptor
and its expression to form latent tumour cell which grows and develops
into differentiated tumour that undergoes progression to form
independent undifferentiated cancer, show positive events that are
modified by macromolecular synthesis, control of differentiation, action
of genes, co-carcinogens, growth stimulants, inhibitors, nutritional
status, endocrine status, surgery, radiation, chemotherapy,
immunotherapy and immunologic competence (Miller and Miller, 1965,
1971; Weisburger et al., 1972; Irvin, 1973). If these steps are not controlled
by the above named modifiers, malignancy results.
A malignant cell is a tumour that invades and destroys the tissue
in which it originates and can spread to other sites in the body via the
blood stream and lymphatic system. It is a disorder that is cancerous and
life-threatening if untreated. Benign describes a tumour that does not

80
invade and destroy the tissue in which it originates or spread to distant
sites in the body i.e. a tumour that is not cancerous. It is any disorder
that does not produce harmful effects.

Contamination of Foods by Microbes

This occurs due to improper cooking, poor hygiene and handling of food.
 E. coli bacterial contamination of raw milk, water, vegetables and
undercooked meat causes stomach upset, nausea and vomiting.
 Clostridium botulina contamination of canned food causes
diarrhoea and vomiting resulting in dehydration. Fluid
replacement therapy is advised.
 Salmonella contamination of egg, poultry, beef and dairy
products result in abdominal cramps.
 Eating foods (meat, poultry) and foods prepared 24 hours before
consumption that are not reheated properly and contaminated
by Clostridium perfringens causes fever with gastrointestinal
symptoms.

As a precautionary measure, one should cook food to the appropriate

temperature, avoid cross contamination of foods, wash your hands and
cooking utensils properly and frequently, and ensure immediate
refrigeration of leftovers (foods).

Toxicants Produced During Heat Treatment of Foods

Heating causes pyrolysis of some food nutrients such as fats and oils.
Major products of pyrolysis of fat are the polycyclic aromatic
hydrocarbons (PAH) and the heterocyclic amines, and these are potential
cancer-causing agents. The heterocyclic amines (HCAs) are the products
obtained from the amino acids, mainly tryptophan. The source of PAHs
is the smoke generated from pyrolyzed fat (especially from meat with the
highest fat content) dripped from the meat onto the hot coals. Polycyclic
aromatic hydrocarbon carcinogens had long been reported in chimney
smoke (Pott, 1775). The induction of cancer by PAH from smoke had also
long been reported (Wolf, 1952).
Vice-Chancellor Sir, during smoking as in the preparation of
‘suya’, some substances deposited on the food (meat) are carcinogenic

81
and teratogenic. They increase the risk of gastrointestinal cancer and
affect sperm cell formation in populations where there are high intakes of
smoked foods. Individuals who have formed the habit of over-
consumption of ‘suya’ and -*also anu kporo nku n’eju onu (dried meat
that fills the mouth) and ‘washing down’ with litres of alcoholic drinks
are hereby warned to desist from such practice by moderating intake
because they are at high risk of having colonic or gastrointestinal cancer.
Cooking in a way to prevent the smoke from dripped fat, reduces or
eliminates the PAH. Three potent polycyclic aromatic hydrocarbon
(PAH) carcinogens namely 20-methylcholanthrene, 3, 4-benzo(α)pyrene
and 7,12-dimethyl-benzanthracene have also been detected in fish
samples that were smoked under local conditions (Onyeike, 1982).

Squamous cell Basal cell Melanoma

Persistent bleeding is Thus is the most common This deadly cancer is usually
common with this rarely skin cancer. This nonlethal larger than a pencil’s eraser,
deadly cancer. Wartz, scaly blemish can be a shiny bump, multicoloured and changes size
patches, open sores and a pink growth, a scar-like area and shape. It also shows
rapidly growing bumps are or an open sore that does not asymmetry and has uneven
telltale signs. heal easily. borders.

Plate 14. Skin cancers induced by carcinogens in foods.

Source: http://blog.drseymourweaver.com/dermatology-blog/wpcontent/uploads
/2012/02/skin-cancers.gif

82 Smoked Meat (Suya)

Consumers of Suya
 Smoked Chicken
Fried fish

Plate 15. Consumers of smoked meat (suya), fried fish and smoked chicken

High temperature cooking of red meat (beef and pork), fish, chicken
produces heterocyclic amines. High-temperature cooking (frying and
broiling) produce higher concentrations of HCAs than low-temperature
cooking (boiling and use of microwave).
The mutagenic potency of HCAs raise concern about possible
carcinogenicity. These toxicants (PAHs and HCAs) can be reduced by
(i) avoiding the charring of food during cooking.
(ii) Avoiding direct contact of meat and fish with naked gas flame or
charcoal.
(iii) Cooking meat and fish in aluminium foil and mechanical
separation of charred parts of meat and fish from the edible
portion.
Acrylamide, which is a neurotoxin and a known carcinogen in rats and
humans is produced when starchy foods are cooked at high heat such as
when foods are deep fried, baked, roasted or toasted, processed
poultry products, instant malt drinks, chocolate powder and roasted
0
coffee powder processed at temperature above 120 C or more (Kazmi,
2005). Hence, high intake of fried and baked foods (potato chips,
processed cereals, cookies and bread) should be discouraged especially
by cigarette smokers because cigarette smoke is also a source of
acrylamide.
The mechanism by which acrylamide gets into fried and baked
food: The amino acid, asparagine found in starchy foods at temperatures
0
above 100 C binds with glucose and in the acrylamide pathway, a

83
maillard product, N-glycoside cleaves at a carbon-nitrogen bond,
producing the carbon skeleton and a terminal amide group at
asparagines, which transits to acrylamide. Food fried in vegetable oils
and trans fat are high-risk foods that affect human health when they are
not eaten in moderation, as part of a well-balanced diet (Meyers, 2006).
Fried foods contain polyunsaturated fats which become rancid when
exposed to oxygen and produce large amounts of free radicals which have
damaging effect in the body. The oils can cause aging, inflammation,
cancer and weight gain.
Fried foods are high in fat and salt content, low in calcium and
fibre and contribute to obesity and chronic diseases. Fibre lowers
cholesterol level and increases the removal of bulk stool thus decreasing
the risk of cancer and cardiovascular disease. High salt content
contributes to high blood pressure, stroke and kidney problems. Low
calcium leads to increased risk for osteoporosis and bone fractures.
Eating fried food away from home is associated with dietary
patterns leading to body weight gain and chronic diseases. For example,
drinking sugar-sweetened beverages is associated with weight gain; high
intake of trans fat is linked to heart disease; low intake of fruits and
vegetables is linked to cancer, and a high glycemic load (glucose
consumption) is associated with type 2 diabetes (Antonios and
MacGregor, 1996).
In an interview with UNIPORT Weekly, Orisakwe (2011) asserted
that “What is eating us up is what we eat”. He described the general
eating habit of Nigerians as poor, and stated that we eat all sorts of food,
and no one has ever bothered to analyze the contents of what is
consumed to determine their suitability for our total well being. As
rightly stated by the Clinical Pharmacist at the University of Port
Harcourt, Nigeria, Health Practitioners have not been given enough
impetus to function effectively in the country and wondered why
Nigerians preferred processed foods in place of abundant natural foods
that would enhance their health, emphasizing that it is improper to
throw away what is healthy and go for junks that compromise our total
well being.

84
 SUMMARY OF MY RESEARCH CONTRIBUTIONS TO KNOWLEDGE
Vice-Chancellor Sir, on the research contributions which led to my
elevation to the rank of Professor of Biochemistry, my research and
publication after professionship and which together form the basis for
what I now profess, permit me to take this distinguished audience
through the lines below.

1. Proximate/Nutrient and Antinutrient Composition of Foods

Raw vegetable seeds of oil bean, melon, castor oil and fluted pumpkin
used as soup condiments in Nigeria East of the Niger were evaluated, and
found to be good sources of lipids 40-54%, proteins 24-34%, ash 2.94-
5.96%, vitamin C, energy 536-639 kcal/100g and the minerals calcium,
magnesium, zinc, iron and manganese (Onyeike and Onwuka, 1999).
Compared to cooked and unfermented seeds, cooking followed by
fermentation decreased ash, carbohydrate, vitamin C and minerals and is
recommendable since it increased protein, fat, energy content and
caused the destruction of toxicants, improvement in texture and taste,
enhanced flavour and increased nutritional value and shelf-life.
Through histochemical studies, we found tannins in ripe and
unripe fruits of some cultivars of plantain, cooking and desert bananas
with the highest concentrations of tanniniferous cells in the epidermis
followed by the ground tissue of the peel of unripe fruits (Osuji et al.,
1998). It was also found that the activity of the antinutrient, tannin was
considerably reduced by ripening. The quantity and distribution of
tannins in the Musa cultivars investigated were found to be
taxonomically undiagnostic.
The effect of cooking and roasting on the nutrient composition
and levels of some toxicants in three species of cocoyam tubers
(Xanthosoma saggitifolium, Colocasia esculenta and Colocasia
antiquorum) was investigated (Onyeike and Nwideezia, 2001). The three
cocoyams were found to be good sources of carbohydrate, fibre, ash and
the minerals copper, zinc, iron, chloride and sulphate, but low in protein
and fats. Cooking and roasting increased ash, fibre, minerals, but

85
decreased protein, fat, carbohydrate, energy and the toxicants (oxalate,
saponins, phytate and cyanogenic glycosides) thereby enhancing their
consumption.
Four edible fats and oils (groundnut oil, red palm oil, blue band
margarine and butter) consumed in most Nigerian homes have been
shown to be of high nutritional and calorific value, and hence good in
terms of edibility especially red palm oil and groundnut oil which
contained higher degrees of unsaturation (Onyeike et al., 2001). The
samples were low in moisture, crude protein, and carbohydrate, but high
in crude fat (83-94%) and energy content (817-869 Kcal/100g). There
were good physicochemical properties as well as excellent organoleptic
properties (colour, odour and texture) as assessed using a nine-point
Hedonic scale of 1 = dislike extremely and 9 = like extremely.
Our study on Nigerian oil seeds (castor, coconut, dikanut,
groundnut, melon, oil bean and palm kernel) showed excellent nutrient
and energy composition, and good physicochemical properties in terms
of colour, specific gravity, melting point, setting point, acid value, iodine
value, peroxide value and percent free fatty acid as oleic acid and
saponification number (which ranged from 338 in coconut seed to 979 in
melon seed (Onyeike and Acheru, 2002). The oil extracts were reported
useful as edible oils (low free fatty acid and peroxide values, low iodine
values and susceptibility to oxidative rancidity) and for industrial
applications as in soap production. Our findings in this work offer a
scientific basis for the use of the seeds both in human diet, and the
manufacture of some commercial products.
Raphia palm beetle (Oryctes rhinoceros) is called Osori, tam and
utukuru by the Ijaw, Ogoni and Ibo respectively. Raphia palm weevil
(Rhyncophorus pheonicis) is called eruru in Ibo and nten in Efik and
Ibibo. Both are called “diet” if you are travelling from Patani to Benin
through Warri. Vice-Chancellor Sir, on account of our work on these
samples, we received a letter of commendation from an Association of
Ph.D Students in America’s best Ten Universities. It was shown that the
larvae of these lesser known food materials have the potential of
providing large amounts of nutrients, (mainly proteins, fats, ash) and
high nutritive and energy value especially the palm weevil with good
complement of iron, copper and phosphorus (Onyeike et al., 2005). They

86
were adjudged very beneficial in meeting human requirements for amino
acids of proteins that are indispensable, the high concentration of various
essential and non-essential amino acids as well as the sulphur-containing
amino acids. In both samples, valine was found to have the lowest
chemical score of 51.2% which revealed it as the most limiting amino acid
for protein quality.
Trace metal (iron, zinc, copper, nickel, cadmium) levels in staple
foods (yam, cassava, cocoyam and maize) from oil-producing areas of
Eleme, Ogoni, Okrika and Nembe were studied and found to be
significantly higher than values from non oil-producing area of Abakaliki
(Akaninwor et al, 2006).
Quantitative high performance liquid chromatographic analysis
of the leaves of Acalypha wilkesiana Muell Arg. was investigated, and the
leaves were found to be rich in flavonoids, carotenoids, phytosterols, but
poor in simple terpenes indicating that the leaves are potential sources of
allelochemicals and neutrceuticals thereby justifying their use in
traditional medicine (Onyeike et al., 2010). For instance, the flavonoids
which are pigments that are responsible for the colours found in fruits,
vegetables, herbs, seeds, spices, stems, flowers (Middleton et al., 2000)
are important in human diet as antioxidants and anti-inflammatory
agents (Soetan, 2008) and are associated with reduced risk of cancer and
cardiovascular diseases (Middleton et al., 2000; Grubesic et al., 2007).
We investigated the genus Sanseviera whose common names
include mother in-laws tongue, devil’s tongue and snake plant (USDA,
2008) comprising about 60 species (Evans, 2005).
Using gas chromatography, the presence of total alkaloids,
allicins, glycosides and saponins was established and the levels quantified
in the leaves of Sanseviera liberica Gerome and Labroy (Ikewuchi et al,
2011). On dry wet basis, the leaves were rich in alkaloids (317.4mg/kg) low
in allicin (3.815mg/kg) and saponin (1.933mg/kg) and lowest in glycoside
(0.075mg/kg), and these findings lend support to the use of the plant in
traditional medicine for the treatment of asthma, abdominal pains,
diarrhoea, eczema, gonorrhoea, haemorrhoids, hypertension, piles,
sexual weakness, snake bites and wounds of the foot (Gill, 1992; Adeyemi
et al., 2009).

87
 Our evaluation of the nutrient and antinutrient status of the
traditional foods (Onunu and Mgbam) of the Ikwerre people of Nigeria
showed good nutrient composition with the values of protein, fat, ash
and energy higher in Mgbam than in Onunu and the reverse was
obtained for values of carbohydrate, fibre and moisture (Amadi et al.,
2011). Although, values of antinutrients (tannins, cyanogenic glycosides,
flavonoids and oxalates) were higher in Mgbam compared to Onunu,
they were in general of physiologically tolerable levels and further
decreased by heat treatment.
We found in these traditional diets, low levels of saturated and
high levels of unsaturated fatty acids, with a profile of essential and non-
essential amino acids whose chemical scores were comparable to those of
hen’s egg (Amadi et al., 2011). Methionine with a chemical score of 28.6%
was the limiting amino acid in Onunu, while valine with a chemical score
of 71.3% was the limiting amino acid in Mgbam making the latter, the
best of the two diets nutritionally.
Our work on spices showed that in M. myristica (Ehuru), crude
protein, crude fat, total carbohydrate and fibre were found to be 10.7,
41.2, 28.8, and 8.60% respectively while in T. tetraptera (uhiorkirihio), the
values were 13.8, 2.10, 69.8 and 3.73% respectively; calorific value
(kcal/100g sample) was higher in M. myristica (539  1.04) than T.
tetraptera (353  0.75) (Agomuo et al., 2011). Essential fatty acids found in
M. myristica were linolenic acid 39.81%, linoleic acid 44.60% and -
linolenic acid 2.37%, while in T. tetraptera were oleic acid 26.97% and
linoleic acid 19.38%; the saturated fatty acids were higher in T. tetraptera
– palmitoleic acid 33.21% and palmitic acid 20.44% compared to values in
M. myristica – palmitoleic acid 0.42% and palmitic acid 5.42%. The
findings indicate that the samples have good nutritional values especially
M. myristica (Agomuo et al., 2011).

2. Studies on Soaking of Food Samples

In order to address the problem of hard-to-cook phenomenon, African
yam bean (AYB) seeds were soaked in water and various concentrations
of sodium chloride (NaCl) and sodium sesquicarbonate
(Na2CO3.NaHCO3.2H2O) solutions. Loss of protein to the soak solution
th
was found to increase with soaking up to the 18 hour, after which a

88
 th
sharp decrease in protein loss occurred at the 24 hour (Onyeike and
Ayalogu, 1996). Protein losses were independent of salt concentrations
due to non-uniform leaching and sample softening was best in sodium
sesquicarbonate solution. It was proposed that the presence of sodium
salts may have resulted in greater softening of the seed by causing a
dissolution of the adjacent hydrogen bonds and rupturing of the cell wall
and middle lamella of the seed microstructure thereby permitting the
release of proteins from the matrix into the soak solutions (Onyeike and
Ayalogu, 1996).
Hydration coefficient (HC) increased as soaking of AYB seeds in
water, NaCl and Na2CO3.NaHCO3.2H2O solutions increased from 6-18hr,
th
but decreased at the 24 hour, and was higher in sodium
sesquicarbonate than sodium chloride at the same salt concentration
resulting in greater reduction in cooking time in samples soaked in
Na2CO3.NaHCO3.2H2O than in NaCl (Onyeike and Uzogara, 2000).

3. Heat Treatment and Proximate/Nutrient Composition of Food

Samples
Our study has shown that heat treatment had no significant (p<0.05)
effect on the proximate nutrient composition and calorific values of
melon seeds, dikanut seeds and cocoyam tubers mostly used as
conventional soup thickeners in Southern Nigeria with melon having the
best nutritive value and is thus recommendable for cooking (Onyeike et
al., 1995).
Since defatting decreased crude fat and energy value and
increased protein, carbohydrate and ash, we recommended that foods
designed to overcome protein malnutrition should be formulated from
defatted and heat processed samples, but defatting should be
discouraged in the context of energy malnutrition.
Investigation of proximate composition of cashew nut seed flour
showed low moisture and carbohydrate content, but high levels of ash,
crude protein and fat, calorific value and mineral elements. The levels of
antinutrients (tannins, oxalates, phytates and cyanogenic glycosides)
were decreased by roasting making the nutrients available for utilization
in the body (Onyeike and Ikuru, 1998).

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 In raw, boiled and fried groundnut seed pastes investigated for
nutrient composition and lipid characterization, crude protein ranged
from 19-28% while crude fat ranged from 25-51%. Heat processing
generally decreased the protein, fat, Fe, Zn, energy content, vitamins A
and C, free fatty acid and peroxide value, but had no significant effect on
Cu, acid and iodine values and saponification number (Onyeike and
Oguike, 2003). These findings may offer scientific basis for the use of heat
processed seeds as food for humans and the oil extracts for the
manufacture of industrial products.
We studied the influence of heat processing (cooking) on the
nutrient composition of vegetable leaves (green leaf, bitter leaf, oha leaf,
hard leaf, water leaf and fluted pumpkin leaf) consumed in Nigeria, and
found them to be good sources of the minerals (Na, Mg, Fe, Zn, Cu) but
poor sources of crude fat and protein, total carbohydrate and calories
(Onyeike et al., 2003). Cooking decreased ash, protein, fat, ascorbic acid
and the divalent metals (Mg, Fe, Zn, Cu) but increased the availability of
the monovalent sodium (Na) in all the samples investigated.
Proximate composition and energy values of raw and heat processed
staple foods (yam, cassava, cocoyam and maize) from oil-producing
(Eleme, Ogoni, Okrika, Nembe) areas of Rivers and Bayelsa States and
Abakaliki (a non-oil producing area in Ebonyi State, Nigeria) were
investigated (Onyeike et al., 2008). The samples were high in moisture
and carbohydrate, but low in protein, fat, ash and calorie. Except for
moisture and ash, the nutrients were generally lower in samples from oil-
producing areas. Heat treatment increased moisture, but decreased other
nutrients and energy values in all the food samples irrespective of source.

4. Processing and the Levels of Toxicants in Foods

The presence of the toxic protein, trypsin inhibitors has been studied in
the African yam bean seeds (Sphenostylis stenocarpa), and through a
kinetic approach, heat treatment was shown to inactivate the African
yam bean trypsin inhibitors in order to improve the protein quality and
derive the full nutritional potential of the pulse (Onyeike et al., 1991).
Vice-Chancellor Sir, I have received several commendations from
individuals and organizations world-wide on the quality of my
publications. I wish to state here that out of the 68 journal articles which

90
I have published in local, international and foreign journals to date, this
article (Onyeike et al., 1991) is adjudged the overall best well-researched
scientific paper. It was accepted for publication without modification by
the Nigerian Journal of Biochemistry and Molecular Biology (an official
Journal of Nigerian Society of Biochemistry and Molecular Biology). It
was also accepted for publication without modification by Food
Chemistry – a foreign Journal based at the University of Reading, United
Kingdom, and the University of Reading is the World’s Centre of
Excellence for Food Studies. Till date, I have received a total of 62
requests for reprints of that article world-wide.
We investigated the effects of extraction time, dilution factors
and heat processing on trypsin inhibitor activity, and found extraction
time of 1 and 3 hr adequate to extract maximum amount of the inhibitor
from raw and heat processed African yam bean samples respectively
(Onyeike and Ayalogu, 1999). Dilution factors of 1:50 and 1:10 dilutions
were best in extracting trypsin inhibitors from raw and heat processed
samples. 1:50 dilution gave % trypsin inhibition of 52.4% while 1:10
dilution gave 51.9% and both fell within the range of 40-60% inhibition
reported by Kakade et al., (1974). Trypsin inhibitor activity (TIA)
decreased over time of heat treatment in a manner that indicated first
order reaction kinetics when the bean flours were heated between 70 and
0 0
80 C. At 100 C, loss in TIA with time of heat treatment was found to be
biphasic.
We have also shown that variety (marble or brown) did not
considerably affect the nutrient values of raw, autoclaved and cooked
AYB, though the proximate composition and levels of the toxic factors
(cyanogenic glycosides, oxalates, tannins, saponins and trypsin
inhibitors) were slightly higher in the brown compared to the marble
variety (Onyeike and Omubo-Dede, 2002). Autoclaving decreased these
toxicants which were further reduced by cooking to physiologically
tolerable levels.
In our study on the effect of ripening on the nutrient and
antinutrient factors in Mexican avocado pear, we reported that ripening
- -
increased crude fat, ash, calorific value; Na, K, Zn, Mg, Ca, Cl , NO3 and
3-
PO4 (Onyeike et al., 2002) but did not significantly (p≤0.05) affect crude
protein, fibre and total carbohydrate. The concentrations of the

91
antinutritional factors – cyanogenic glycosides, tannins, saponins and
oxalates were found to be significantly (p<0.05) decreased by ripening to
the extent of 50%, 66.7%, 42.3% and 75.0% respectively.

5. Nutritional Evaluation of Protein Quality of Formulated Diets

using Rat Feeding Studies
Our work on the influence of heat processing of African yam bean (AYB)
seed flour on the growth and organ weights of rats indicated that
autoclaving and cooking improved the growth and organ weights of rats
due to heat destruction of toxic factors in AYB especially trypsin
0
inhibitors (Onyeike et al., 1995). Autoclaving at 121 C, 15 psi for 30min
and cooking for 3 hr increased body weight gain by 75.4% and 63.2%
respectively, while feed utilization was increased by 79.6% and 62.9%
respectively.
Our findings (Tables 7a and 7b) in this area of research generally
indicate that heat processing (autoclaving, cooking, oven drying) of food
samples improved the growth and organ weights of rats due to heat
inactivation of the inherent toxicants which are known to be the main
culprits of the poor nutritive value of food materials. Raw food materials
incorporated into the diet depressed the growth of rats and failed to
improve their organ weights resulting in pathological changes such as the
enlargement of the pancreas (pancreatic hypertrophy) and hyperplasia.
Food samples only soaked in water or 4% sodium chloride or 1% sodium
sesquicarbonate did not improve nutritional parameters as well as
absolute and relative organ weights of rats, indicating that the processing
methods were inadequate in destroying and eliminating the toxicants in
natural association with the food samples.
Diets formulated from heat processed African yam bean-rice-
prawn mixture and also cowpea-millet-crayfish mixture could be adopted
as weaning foods due to their high nutritional qualities which are
comparable to that of a commercial infant formula, Nutrend.
In vivo studies was carried out with weanling albino rats of the
Wistar strain fed Onunu and Mgbam traditional diets of the Ikwerre
people of the Niger Delta, Nigeria for 28 days. As reported by Amadi et al.
(2012), body weight change (g) of rats after 28 day-feeding was highest in
Nutrend (84.141.99) followed by Mgbam (54.314.14), Onunu (32.101.14)

92
and lowest in Basal (5.526.38) while protein efficiency ratio was highest
in Nutrend (1.930.13) followed by Mgbam (1.680.03) and lowest in
Onunu (1.110.02). Net protein utilization was 60.00.02 in Mgbam,
55.00.02 in Nutrend and 42.50.03 in Onunu while the biological value
was highest in Nutrend (87.15.90) followed by Mgbam (63.66.54) and
lowest in Onunu (43.85.37).
For each of the organs (heart, kidneys, liver, spleen, pancreas and
lungs), improvement in organ weight was highest in rats fed Nutrend,
followed by rats fed Mgbam, then Onunu and was lowest in rats adapted
to the basal diet (Amadi et al., 2012).

6. Functional Properties of Proteins in Foods

Protein functionality denotes any physicochemical property affecting the
processing and behaviour of protein in the development of new food
systems as presented by the quality attributes of the final food product. It
reflects the complex interactions between the composition, structure,
conformation, physicochemical properties, other food components and
the nature of the environment in which these are associated (Kinsella,
1976).
We evaluated the functional properties of flours of raw and heat
processed melon seed, dikanut seed, cocoyam tuber (Onyeike and
Olungwe, 1998) and African yam bean seeds (Onyeike and Ayalogu, 1999)
and found that the flours exhibited good gelation capacity, oil and water
absorption capacity and stability, foaming capacity and stability and
protein solubility as affected by pH. Minimum protein solubility for
African yam bean was at pH 4.0, and for other samples, it occurred at pH
8.0 showing protein precipitation and isolation at these pH values.
0
Our study showed that heat treatment (autoclaving at 121 C, 15
psi for 15 to 30 min) caused dissociation of protein subunits, increase in
the surface area of the protein and exposed more oil and water binding
sites, but decreased emulsion and foaming capacities and stabilities as
well as protein solubility at every pH investigated due to heat
denaturation of proteins. These findings are important in the
development of new functional products by food industries.

93
Table 7a: Performance characteristics of rats fed different diets for
28 days
Diet BWG( PER TND NPU BV FU Reference
g) % % % (mg
/g)
1. Raw AYB, cooked 32.2 1.22 94.7 48.9 50.2 204 Onyeike
rice and prawn and Morris
mixture (1996)
2. Cooked AYB, 40.9 1.60 99.2 70.7 71.3 263
cooked rice and
prawn mixture
3. Positive reference 64.9 2.52 99.6 72.0 72.3 407
diet, Nutrend
1. AYB soaked in 11.9 0.34 98.2 77.4 78.8 43.9 Onyeike et
water for 18hr al. (1998)
2. AYB soaked in 1% 12.4 0.38 99.6 81.7 82.1 51.6
akanwu for 18hr
3. Positive reference 61.2 1.28 99.4 61.2 61.5 205
diet, Nutrend
1. Raw AYB 14.2 0.27 93.6 56.8 60.7 - Onyeike et
al. (1999)
2. AYB autoclaved at 60.6 1.83 96.6 76.9 79.6 -
1210C, 15psi for 30
mins
3. Nutrend 80.0 2.60 98.4 86.8 88.2 -
(reference)
1. Oil polluted 32.8 1.10 97.5 49.8 50.5 - Onyeike et
catfish al. (2000)
2. Unpolluted catfish 65.0 1.74 97.3 52.0 53.3 -
3. Reference (whole 107 1.69 98.3 45.3 45.3 -
Nutrend)

BWG = Body weight gain at the end of feeding studies

PER = Protein efficiency ratio TND = True nitrogen digestibility
NPU = Net protein utilization BV = Biological value
FU = Feed utilization

94
Table 7b: Performance characteristics of rats fed different diets for
28 days
Diet BWG(g) PER TND NPU BV FU Reference
% % % (mg/g
)
1. Oven dried 7.50 0.30 96.3 49.5 51.4 35.5 Ayalogu et
(800C for 24 al (2003)
hr) of larvae
of raphia
palm beetle
2. Oven dried 13.3 0.35 98.1 59.1 60.2 41.4
(800C for 24
hr) of larvae
of palm
weevil
3. Reference 113 1.67 94.2 55.4 58.8 267
Nutrend
1. Raw cashew 28.1 1.71 87.5 52.9 60.5 228 Onyeike
nut seed and
flour Nkwuzor
(2006)
2. Cashew nut 64.2 2.65 85.3 70.8 83.0 324
seed flour
autoclaved
at 1210C,
15psi for 90
min
3. Whole 112 3.03 93.0 81.9 88.1 509
Nutrend
1. Raw 71.0 1.71 96.1 69.0 71.8 222 Onyeike
cowpea/coo and Uzoka
ked millet/ (2006)
dried
crafish mix
2. Cooked 82.3 1.96 95.5 73.6 82.4 316
cowpea/coo
ked millet/
dried
crafish
mixture
3. Whole 129 2.62 93.1 85.8 92.2 427
Nutrend
BWG = Body weight gain at the end of feeding studies
PER = Protein efficiency ratio TND = True nitrogen digestibility
NPU = Net protein utilization BV = Biological value

95
FU = Feed utilization

7. Environmental Biochemistry
We investigated the physicochemical properties and inorganic ion levels
of soils and streams/rivers in oil-producing communities of Yorla,
Zaakpon and Goi in Ogoniland, Niger Delta, Nigeria as affected by crude
oil spillage, and found the soils and streams polluted with crude oil
(Onyeike and Ogbuja, 1999; Onyeike et al., 2002). Our findings showed
significantly (p ≤ 0.05) higher concentrations of exchangeable cations
and trace metals (Ca, Mg, Na, K, Cu, Mn, Fe and Zn) and heavy metals
(Pb, Cd, Cr, Ni and As) in the polluted soils and streams compared to
their controls, and values were also significantly higher in Yorla, Zaakpon
and control compared to Goi North, Goi South and Goi control. Values of
trace and heavy metals and the anions phosphate, nitrate, sulphate and
chloride indicated that the soils and rivers of Yorla, Zaakpon and Goi
were generally polluted with inorganic ions, with Yorla and Zaakpon soils
and rivers more polluted than Goi. The soils and rivers were considered
unacceptable for domestic and industrial uses if not treated, and soils
(farmlands) may also become unsuitable for agricultural purposes.
The effect of consuming fish caught from crude oil contaminated
fresh water from Adanta stream, Isiokpo in Ikwerre, Rivers State on the
relative organ weights and carcass lipid levels of rats was investigated
(Ibegbulem et al., 2006). It was found that relative organ weights of rats
fed diets formulated from polluted and unpolluted fresh water fish
samples did not vary significantly, but carcass lipid levels of rats fed
polluted samples increased significantly (p = 0.05) over those of rats
adapted to unpolluted freshwater fish sample diets.
The growth performance and nutrient composition of fluted
pumpkin (Telfairia occidentalis) planted in soil polluted with varied
levels of water-soluble fractions (WSF) of crude oil (Bonny light) were
evaluated to assess the effectiveness of organic nutrients (poultry manure
and sawdust) in the remediation of WSF-contaminated soils (Wegwu and
Onyeike, 2006). Our findings showed that application of the WSF
delayed germination. However, treatments with sawdust and poultry
manure enhanced the germination and nutrient potential. Generally, the

96
increased percentage of germination in the nutrient-supplemented WSF-
polluted soil was a demonstration of the efficiency of sawdust and
poultry manure in the remediation of oil-polluted soils.
Mucuna pruriens, a fast-growing, high biomass – accumulating
plant was investigated to underscore its suitability for metal (cadmium
and copper) extraction in an oil spill condition, and process
enhancement was made using NPK, urea and poultry manure fertilizers
-1
(Nwaichi et al., 2009). The plant accumulated up to 32mg kg cadmium
-1
and 62mg kg copper in the tissue of both root and shoot and achieved
above 50% contaminant removal for both cadmium and copper. Based on
plant growth parameters measured (plant height, leaf area, produced
biomass and vigour) poultry manure assisted phytoextraction was the
best option compared to NPK and urea.
The toxic effects on Vigna subterranean legume plants grown for
two weeks in a simulated petroleum (up to 50ml/kg soil) contaminated
soil was investigated using polluted soil unamended or amended with
NPK, urea or poultry manure. The amendments reduced the inherent
phytotoxicity of the petroleum sample and the measurable uptake of
contaminants (Nwaichi et al., 2010). We recommend poultry manure for
such management practice especially at lower doses of the contaminants.
Rats fed un-amended contaminated diet for 10 days were found to suffer
enlarged stomach wall, poor relative growth rate, poor body weight gain
and protein efficiency ratio as well as pancreatic enlargement.
The potential of bambara groundnut (Vigna subterranean) for
phytoextraction of copper in a crude oil contaminated soil, to which
amendments (poultry manure, NPK and urea) were added to increase the
metal uptake and translocation to aerial biomass was investigated
(Nwaichi et al., 2010). It was found that poultry manure was the most
effective amendment for enhancing copper uptake and translocation
-1
with shoot tissue copper levels of 118mg kg compared to 98.3 and 93.0
-1
mg kg obtained for NPK and urea amendments respectively, Hazard
characterization or risk assessment with rats on inherent
biomagnifications due to contaminant load showed poor organ weights
and optimum digestibility, poor rat growth and pancreatic hypertrophy
in rats adapted to the diet as compared to controls due to the potential
toxic effect of phytoextracted or bioaccumulated copper.

97
 Using pot experiments and simulated crude oil polluted soils to
which chicken manure, urea and NPK fertilizers were incorporated as
biostimulators for copper uptake, Nwaichi and Onyeike (2010) found
that, poultry manure assisted phytoextraction of copper with Mucuna
plants by all indices than urea and NPK.
Mucuna showed greater copper tolerance (higher accumulation
of copper in the shoots compared to the roots) which is advantageous at
green remediation. Although there was no measurable copper uptake
with urea amendments, it could be useful for enhancing contaminant
mobilization from soil samples.
We investigated the hydrocarbon (HC) contaminant removal
efficiency of Bambara groundnuts and biomagnification in un-amended
or amended (with NPK, urea, poultry manure) soil samples and found
that amendments improved phytoextraction thus: urea (63.4%), NPK
(66%), poultry manure (70.0%) for polycyclic aromatic hydrocarbon
(PAH) and urea (78.8%), NPK (79.8%), poultry manure (87.9%) for BTEX
(benzene, toluene, ethyl benzene, xylene) (Nwaichi et al., 2010). Hazard
characterization using rat-feeding studies for 28 days showed that the
potentially toxic PAH and BTEX diets affected feed digestibility resulting
in decreased sleeping time and poor growth as well as pancreatic
hypertrophy and hyperplasia in test rats compared to control.
Hypertrophy describes increase in the size of a tissue or organ
brought about by the enlargement of its cells rather than by cell
multiplication (as during normal growth and tumour formation).
Muscles undergo this change in response to increased work. Hyperplasia
is the increased production and growth of normal cells in a tissue or
organ. The affected part becomes larger but retains its normal form as in
benign prostatic hyperplasia. During pregnancy, the breasts grow in this
manner.
Comparing chicken manure and urea fertilizer as potential soil
amendments for enhanced phytoextraction of heavy metals, Nwaichi et
al. (2010) found that chicken manure caused less cadmium solubilization
and increased shoot cadmium accumulation compared to urea fertilizer.
Chicken manure amended treatment showed greater cadmium tolerance
for Mucuna pruriens and Sphenostylis stenocarpa, and the latter did not
support phytoextraction of cadmium. Even under conditions of heavy

98
metal (Fe, Cd, Cu) stress, amendments especially with chicken manure
can increase biomass production and nutrient (Ca, Mg and nitrate)
uptake and distribution.
Growth performance and phytoremediation of soil artificially
contaminated with crude oil (50ml/ug soil) using Centrosema pubescen
for 12 weeks, with the soil either un-amended or amended with NPK,
urea or chicken manure were investigated by Gas Chromatographic
analysis (Nwaichi et al., 2011).
The greatest percent removal of BTEX and carcinogenic PAH
occurred at the highest contaminant doses of 10mg/kg BTEX, 43mg/kg
PAH and 561.3mg/kg oil and grease. There was no measurable plant
uptake of contaminant and inhibition of plant growth was proportional
to the dose of crude oil but manure amendment was very effective at
reducing growth inhibition and phytotoxicity.
Investigation of soil metal clean-up by Centrosema pubescen
plant which showed the ability to survive on soils containing
hydrocarbons and metal contaminants in a simulated study, young
seedlings grown in bonny light crude oil contaminated soils were found
capable of enhancing significant reduction of large amounts of PAH and
heavy metal (cadmium, copper and iron) contaminants, and clean-up
improved with biostimulation using poultry manure which also increased
plant root nodulation and hence, microbial action (Nwaichi and Onyeike,
2011).
In our study on the interaction of selected minerals with organic
pollutants, it was found that soil minerals affected the dynamics and
transformations of organic materials and metabolic processes in a
stressed soil type (oil spill site) with modifications due to clean-up
(Nwaichi and Onyeike, 2011).
The assessment of pH variation and lipase activities as markers
of crude oil bioremediation using chicken drops for bioaugmentation of
crude oil polluted site has been reported (Uwakwe et al., 2012). pH of
topsoil of the bioaugmented site increased from 6.89±0.01 to 7.90±0.05
while for the control it increased from 4.42±0.01 to 5.27±0.02 and for the
natural attenuated site, values increased from 4.68±0.29 to 5.63±0.01.
Lipase has been found useful in monitoring bioremediation of crude oil

99
spillage by its ability to degrade petroleum hydrocarbons and utilize
them as both energy and carbon sources.

8. Chemical and Sensory Evaluation of Foods

In South East Nigeria, melon fungus (MF) is called ike usu or ero usu. Ero
is mushroom and usu is melon fungus, and MF is a soup thickening agent
which is combined with melon seed paste in the preparation of the
popular Nigerian egusi soup.
Our study showed that processing of MF into melon fungus cake
(MFC) used to eat oil-bean salad, stockfish and drink palm wine or beer
increased its moisture content, ash, crude fat, fibre, energy value and
minerals, but decreased protein, carbohydrate and ascorbic acid
(Onyeike and Ehirim, 2001). Evaluation of the sensory attributes of MFC
by 20 members of the panel using a nine-point Hedonic scale where 1 =
dislike extremely, 2 = dislike very much, 3 = dislike moderately, 4 =
dislike slightly, 5 = neither like nor dislike, 6 = like slightly, 7 = like
moderately, 8 = like very much and 9 = like extremely, showed that
aroma, mouth feel and overall acceptability (6.85 ± 1.87, 6.90 ± 0.79 and
8.00 ± 0.88 respectively) were higher in MFC than MF (4.95 ± 1.64, 3.80 ±
1.88 and 6.35 ± 1.14 respectively), but colour and sourness did not differ
significantly (Onyeike and Ehirim, 2001).
Our mineral and sensory evaluation of “Onunu and Mgbam”
traditional diets of the Ikwerre people of Nigeria using the method of
Onyeike and Ehirim (2001) showed them to be composed of good
mineral element (K, Ca, Mn, Cu, Zn, Mg, Na, Fe) status and organoleptic
properties – appearance, taste, aroma, texture, colour, and in terms of
overall acceptability, Mgbam (with a mean score of 8.10 ± 0.64) was more
acceptable than Onunu with a mean score of 7.95 ± 0.68 (Amadi et al.,
2012).

9. Medical Biochemistry, Enzymology and Toxicology

In this area of research, Uwakwe and Onyeike (2003) studied sickle cell
haemoglobin (HbS) gelation and rate of osmotic fragility of HbS red
blood cells, and found that at nicotinic acid (a vitamin) concentrations of
1.0mM and 10.0mM, HbS gelation (polymerization) was reduced by 8.93
and 21.4% respectively after a 10 min incubation, while HbS red blood cell

100
haemolysis was reduced by 18.5 and 50.0% respectively in a concentration
- dependent manner. This nutritional prophylactic, nicotinic acid (a
vitamin) was therefore considered a necessary and beneficial factor in the
diets of sickle cell patients and could be exploited in the nutritional
management of sickle cell disease.
Our work on the protein levels in the urine of 90 pregnant and
30 non-pregnant women in Rivers State, Nigeria showed that due to high
protein diet, protenuria occurred during pregnancy (56.3mg/100ml urine
compared to 35.3mg/100ml for non-pregnant women) and values
decreased with age of pregnancy from 56.3mg/100ml at the first trimester
to 28.3mg/100ml at the third trimester (Ibeh et al., 2006). This finding
may offer scientific basis for the monitoring and treatment of pregnant
women for healthy living and safe delivery of their babies.
We screened for health status through the activities of liver
marker enzymes in sera of sixty (60) pregnant women from oil-producing
areas (Eleme, Ogoni, Okrika, Nembe) and 15 women from non oil-
producing area (Abakaliki) feeding on staple foods from these areas
(Akaninwor et al., 2006). Higher activities of the enzymes alanine
transaminase (ALT), aspartate transaminase (AST) and alkaline
phosphatase (ALP) which were obtained in pregnant women from oil-
producing areas compared to those from non-oil producing area in the
first, second and third trimesters were indicative of possible
susceptibility to jaundice and hepatitis and may be responsible for
neonatal jaundice often found in such areas. Constant monitoring of the
activities of these enzymes as routine antenatal check-up in pregnant
women from oil producing areas is advocated.
In a review on obesity and chronic diseases – the changing
nutritional pattern in Nigeria, Nwosu and Onyeike (2009) warned against
the changing lifestyle which is being more sedentary due to increased
civilization and consumption of excess fat in convenience foods, that play
a role in the aetiology of obesity. There should be promotion of food and
lifestyle choices that reduce the risk of chronic diseases (heart problems,
cancers, arthelerosclerosis, stroke/hypertension, type 2 diabetes mellitus)
by emphasizing fitness to reduce weight, eating whole grains, legumes,
herbs, spices, fruits, vegetables, fish and meat and cutting down on
intake of smoked red meat, alcohol, salt, sugar, foods containing

101
contaminants and toxicants and finally, maintaining a positive outlook in
life.
Sansevieria liberica Gerome and Labroy is a plant commonly
called bowstring hemp. Its roots and leaves are used in traditional
medicine for the treatment of asthma, diarrhoea, abdominal pains and
hypertension (Gill, 1992; Adeyemi et al., 2009).
The aqueous leaf extract which we administered to salt-loaded
rats did not affect liver and kidney functions, produced higher plasma
calcium and potassium levels, red cell and white cell counts and
significantly lowered plasma sodium and chloride levels (Ikewuchi et al.,
2010). Our findings support the use of the plant in the management of
hypertension, and suggest that the extract may be a potassium sparing
diuretic whose antihypertensive action may be mediated through
alteration of plasma sodium and potassium levels or increases in muscle
tone due to changes in plasma calcium levels.
We have reported similar findings with aqueous leaf extract of
Sansevieria senegambica Baker, which in addition produced leukocytosis
but had no negative effects on enzyme markers of liver and kidney
functions (Ayalogu et al., 2011).
Sansevieria senegambica Baker which is also called mother in-
law’s tongue, devil’s tongue and snake plant is used in traditional medical
practice in Southern Nigeria for the treatment of bronchitis,
inflammation, cough, boils and hypertension. Our study on the aqueous
leaf extract of the plant showed that it can protect against
artherosclerosis and cardiovascular complications either through its body
weight-reducing effect or lowering of its plasma total low density
lipoprotein cholesterol thereby confirming its use in the management of
hypertension (Ikewuchi et al., 2011).
Tridax procumbens commonly called coat buttons, tridax daisy
or simply tridax is a plant that is traditionally used to manage
hypertension (Salabdeen et al., 2004). Aqueous extract of the leaves
orally administered daily to sub-chronic salt-loaded rats at 150 and
200mg/kg body weight was found to lower mean daily weight gain,
plasma LDL (the bad cholesterol), total and VLDL cholesterol, and
increased plasma HDL cholesterol (good cholesterol) without significant
alterations in organ sizes and weight (Ikewuchi et al., 2011). Our findings

102
indicate a likely dose-dependent cardioprotective potential of the extract
on the hypertensives.
The leaf of Acalypha wilkesiana plant is commonly called copper
leaf, Joseph’s coat, fire dragon, beef steak plant and match-me-if-you-can
(Christman, 2004). It is found widespread in the tropics of Africa,
America and Asia. It is used in traditional health care practice for the
management of hypertension, gastrointestinal disorders, fungal skin
infections, diabetes mellitus, headache, colds, malaria (Akinyemi et al.,
2005), breast tumors and inflammation (Bussing et al., 1999; Taraphdar et
al., 2001). We found that the aqueous extracts of the leaves administered
to sub chronic salt-loaded rats lowered the systolic, diastolic and mean
arterial blood pressures of the test rats and also lowered and stabilized
pulse rates in comparison to the test controls, thereby confirming the
antihypertensive activity of the leaves, and supports their use in
traditional medicine for the management of hypertension (Ikewuchi et
al., 2011). We also found that the daily oral consumption of an aqueous
extract of the leaves was prophylactic to carbon tetrachloride poisoning
as treatment with the extract protected the rat liver against carbon
tetrachloride-induced hepatotoxicity/hepatic cytotoxicity, thereby
justifying the use of the plant extract in African traditional health care for
the management of liver problems (Ikewuchi et al., 2011).

10. Pharmacological Biochemistry and Toxicology

In this field of research, we have demonstrated that on dry weight basis,
the leaves of Sanseviera liberica Gerome and Labroy is rich in crude
protein (49.8%), ash (6.72%), moisture (56.1%), fibre (13.4%); but low in
crude lipid (0.23%) and carbohydrate (9.32%), while phytochemical
screening showed the presence of alkaloids, carotenoids, flavonoids,
phytates, saponins and tannins (Ikewuchi et al., 2010). The study has
shown the sample as a potential source of protein, ash and fibre, and
supports the medicinal use of the plant. Similar findings were made with
Acalypha wilkesiana in phytochemical composition; only that higher
nutrient values on dry weight basis were obtained for crude fibre (51.1%)
and total carbohydrate (29.5%) with a lower value of 9.29% in crude
protein (Ikewuchi et al., 2010).

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 The African mistletoe (Tapinanthus bangwensis) is a semi-
parasitic plant found growing on a host of evergreen trees and is used by
traditional medicine practitioners to treat cancers, diabetes mellitus and
hypertension (Grossarth-Maticek, 2007; Obatomi et al., 1994 and Kafuru,
1993).
Our work on the crude methanolic extract and fractions of
African mistletoe leaves from Nigeria (this work took my Ph.D student,
Dr. Kingsley C. Patrick-Iwuanyanwu to a Laboratory in Pakistan) on
Wistar albino rats showed that the methanol extract (MeOH) and
partitioned fractions, ethylyacetate (EtOAc) and butanol (BuOH) of the
leaves possess anti-inflammatory effect and this finding may justify the
use of the plant in the management of inflammatory diseases (Patrick-
Iwuanyanwu et al., 2010a). In another study, we found that the extracts
possess strong antioxidant properties and hepatoprotective potentials
against carbon tetrachloride-induced hepatotoxicity (liver damage) in
rats (Patrick-Iwuanyanwu et al., 2010b). We investigated further, the
leaves of Ring worm plant (Senna alata) from Nigeria commonly called
“candle bush” because of the shape of its inflorescence. The Yoruba
people of South West Nigeria call it “Asuwon oyinbo”. In Adamawa and
Taraba States Nigeria, as well as Ghana and Ivory Coast, the root, stem
and leaves are used in herbal medicines to treat burns, skin and wound
infections, diarrhoea and dysentery, gastrointestinal problems, upper
respiratory and urinary track infections and asthma (El-Mahmood et al.,
2008; Irvine, 1961).
Our findings on this plant indicate that crude methanolic extract
(MeOH) and partitioned fractions (EtOAc and BuOH) like those of
African mistletoe possess anti-inflammatory effect justifying the use of
the plant in herbal medicine for the treatment of inflammatory diseases
(Patrick-Iwuanyanwu et al., 2011).
Increase in blood pulse pressure, predicts cardiovascular and
coronary artery disease, myocardial infarction and conjestive heart
failure. We have demonstrated that aqueous extract of the leaves of
Tridax procumbens orally administered daily by intragastric gavages at
150mg/kg and 200mg/kg body weight prevented in rats, the salt loading-
induced upsurge (increase) in pulse pressure, and reduced systolic and
diastolic pressures, and hence can lower cardiovascular risk thereby

104
confirming its use in the management of hypertension (Ikewuchi et al.,
2011).
Because of the ethnopharmacological relevance of the leaves of
Acalypha wilkesiana, we investigated the effect of aqueous extract on the
haematology, plasma biochemistry and ocular indices of oxidative stress
in alloxan-induced diabetic rats (Ikewuchi et al., 2011). Using gas
chromatographic analysis, we identified 29 (twenty nine) known
flavonoids in the extract mainly 29.8% apigenin, 15% quercetin, 11.1%
naringenin, 10.6% kaempferol, 9.05% epicatechin among others.
The extract lowered plasma glucose, enzyme (ALT and AST)
activities, triglycerides, urea, lymphocytes, ocular malondialdehyde levels,
but increased plasma calcium, total white cell and red cell counts, high
density lipoprotein cholesterol and ocular ascorbic acid content. Our
study showed that the extract contained pharmacologically active
compounds, was hypoglycemic and enhanced the functional integrity of
the liver and kidney of diabetic rats, protected against oxidative stress in
ocular tissues, improved the lipid profile and thus exhibited
cardioprotective potential which supported its use in traditional health
care practice for the management of diabetes mellitus and hypertension
(Ikewuchi et al., 2011).
Our recent study confirms the use of Sanseviera liberica Gerome
and Labroy in the management of hypertension in traditional medicine
practice since test rats orally administered the aqueous leaf extract
(250mg/kg body weight) against the control group that received
appropriate volume of water had lowered systolic pressure, reduction in
diastolic and mean arterial pressures, more stable and lowered pulse rate
(Ikewuchi et al., 2012). Fast heart rate is associated with increased risk of
death from cardiovascular and non-cardiovascular causes (Palatini, 1999),
and hence, the lowered heart rate produced by the leaf extract portends
its ability to reduce cardiovascular risk (Ikewuchi et al., 2012).

Recommendations
In 2008, the entire world witnessed food crisis. In order to solve food
problems in Nigeria, it is recommended that
(i) Federal government should fund research in science, technology
and agriculture so that enough food should be produced and

105
 distributed at relatively low cost. The last research grant which I
received from this University was in 1994 and the value was
N50,000.00 (fifty thousand Naira) only, which was not enough to
buy a single chemical, silver nitrate. A research on this type of
grant may start and end at the University Senior Staff Club, and
this does not make sense. What many professors are compelled
to do in their various fields is to climb an iroko tree with bare
hands using feeding money to do research, and a reversal of this
trend is recommended through adequate research funding.
(ii) Policy actions of Nigerian governments should include reduction
of taxes on food and to release food stocks, removal of value
added tax on baby foods, edible oils, rice and grains; reduction of
electricity and utility bills and introducing special programmes
for school and hospital feeding.
(iii) Federal Government should establish a Centre for the
Management of Nutritional Disorders in each of the six geo-
political zones in Nigeria. In these centres (a) Experts in food,
nutrition, dietetics and toxicology should be engaged to run
short-term intensive courses on food and nutrition education for
staff from General and Teaching Hospitals, Clinics, Health
Centres and individuals involved in Catering and Hotel
Management. (b) The Centres should have Rehabilitation Units
where patients with different nutritional disorders are catered
for, free of charge and this should be funded from at least 1% of
the Federal government annual budget. This is important
because it is not acceptable to see, in this technological era,
many citizens of the giant of Africa (Nigeria) suffering from
protein-energy malnutrition, kwashiorkor, marasmus, goitre,
diabetes, diet-related hypertension, marasmic-kwashiorkor and
several disorders due to vitamin and mineral deficiencies.
(iv) A Food Regulatory Body should also be put in place in each State
in Nigeria to ensure that the right type of food is consumed (food
that is balanced, high in nutrients free or unavoidably low in
natural and synthetic toxicants, unadulterated, well processed,
devoid of environmental contaminants and safe). Federal and
State governments are called upon to evolve measures aimed at

106
 helping the populace manage their lifestyles and prevent
disorders due to malnutrition.
(v) Food is a human right and Federal/State governments should
ensure that the citizens are well fed by promoting urban gardens,
and agrarian reforms that include support systems (subsidizing
the cost of fertilizer and ensuring its proper distribution) for
farmers and sustainable agricultural techniques that enhance the
environments.
(vi) Vice-Chancellor Sir, many of our research findings in the area of
Medical and Pharmacological Biochemistry and Toxicology have
shown that the plants we investigated have
ethnopharmacological importance and confirm their use in
traditional health care (medicine) practice for the treatment and
management of abdominal pains, diarrhoea, asthma,
hypertension, carbon tetrachloride-induced hepatotoxicity/
hepatic cytotoxicity, diabetes mellitus, cancers, inflammatory
diseases, cardiovascular (heart) diseases such as conjestive heart
failure, upper respiratory and urinary tract infections. Since it
does no longer make sense to dismiss the findings in herbal
medicine with a wave of the hand, a collaboration between the
Practitioners of Orthodox and Traditional Medicine is strongly
advocated to ensure total health care delivery in Nigeria.

Concluding Remarks
Vice-Chancellor Sir, I have taught at the Primary, Secondary and
University levels from 1977 till date. I have successfully supervised more
than 20 M.Sc candidates, and 6 Ph.D holders who are Lecturers in some
Universities including Uniport, and may in due course become
professors, while other M.Sc and Ph.D supervisees are at various stages of
their research work. With high sense of humility, I wish to leave this
distinguished audience to assess the extent to which I have contributed
to human capital development in Nigeria. I have spent more than 85% of
my life activities since 1991 when I assumed duty in Uniport teaching and
supervising my undergraduate and postgraduate students and
conducting research in Biochemistry. I have till date published a total of
68 articles most of which are in high impact journals across the globe, 10

107
chapters in refereed books, 1 most of which are (one) book which I edited
and have presented 26 papers at conferences with many other
manuscripts at the various stages in the review process. My research
findings have made original contributions to existing knowledge, for
which reprints of my works are from time to time sought for world-wide.
I have served the University of Port Harcourt as Head,
Department of Biochemistry and Chairman, Senate Appeals Committee
on Certificate Verification, and in various professional activities,
University/Public service including serving as External Examiner in many
Universities for the B.Sc, M.Sc and Ph.D degrees and External Assessor of
candidates for Professorial positions. I therefore have a feeling of having
contributed to community service in this country.
Vice-Chancellor Sir, distinguished ladies and gentlemen, this
Inaugural Lecture is therefore a logical outcome of my many years of
teaching, research and community service. I have tried the best I can to
explain in an understandable manner, the concepts associated with the
lecture topic. I had briefly summarized my research contributions which
form the basis for what I profess today, and the direction which I intend
to go in future.
In evaluating the learning experiences from this lecture, I have
two questions for my distinguished audience.
(i) If a woman chooses to consume foods containing appreciable
amounts of nutrients required for growth in a balanced diet that
is well processed and the toxicants appropriately destroyed, is
her life in her hands?

(ii) If on the other hand, a man decides to eat foods deficient in

growth-promoting nutrients, not properly processed and
containing high concentrations of toxic factors that are not
physiologically tolerable, is his life in his hands?

From the Holy Gospel according to John 6:24-27, when the crowd saw
that neither Jesus nor his disciples were there, they themselves got into
the boats and came to Capernaum looking for Jesus. And when they
found him across the sea, they said to him, “Rabbi (Teacher), when did
you get here?” Jesus answered them and said, “Amen, amen I say to you;
you are looking for me not because you saw signs but because you ate

108
the loaves and were filled. Do not work for food that perishes, but
for the food that endures for eternal life which the son of man will
give you.”
Vice-Chancellor Sir, if I should respond to the two questions
above on behalf of this distinguished audience, I would state that we eat
food inorder to sustain life. The food we eat contains nutrients that are
nourishing, and toxicants or antinutritional factors that detract from the
full nutritional potentials of the food we consume. There is then food in
health and in disease. We can decide to eat to live when we consider the
first question above or eat to die considering the second question. The
life of a food consumer is therefore in his hands since he/she has the
prerogative/privilege/right/choice to either eat to live or eat to die.
Vice-Chancellor Sir, Ladies and Gentlemen, I thank you most
sincerely for listening.

109
 REFERENCES

Ackroyd, W.M. & Doughty, J. (1964). Legumes in Human Nutrition. FAO

Nutritional Studies, 19, FAO, Rome, Italy.
Acton, J.E.E.D. (1960). Lord Acton as Professor. In: J.N. Figgis & R.V. Laurence
(Eds.), Lectures on Modern History. London: Macmillan.
Adedoyin, R.A., Mbadab, C.E., Balogun, M.O., Martins, T., Adebayo, R.A.,
Akintomide, A, & Akinwusi, P.O. (2008). Prevalence and pattern of
hypertension in a semi-urban community in Nigeria. European Journal of
Cardiovascular Prevention & Rehabilitation, 15(6), 683-687.
Adesina, O. (2011). Experts advocate regular monitoring of blood glucose.
UNIPORT Weekly, 7(6), 3.
Adeyemi, O.O., Akindele, A.J. & Ogunleye, E.A. (2009). Evaluation of the
antidiarrhoeal effect of Sansevieria liberica Gerome and Labroy root
extract. Journal of Ethnopharmacology, 123(3), 459-463.
Agomuo, E.N., Onyeike, E.N. & Anosike, E.O. (2011). Proximate composition and
fatty acid profile of Monodara myristica (Ehuru) and Tetrapleura
tetraptera (Uhiokirihio). International Science Research Journal, 3, 85-87.
Akaninwor, J.O., Ifemeje, J.C. & Onyeike, E.N. (2006).Changes in the activity
values of selected liver marker enzymes in sera of pregnant women
feeding on staple foods from oil producing areas of the Rivers State.
Nigerian Journal of Science & Environment, 5, 27-34.
Akaninwor, J.O., Onyeike, E.N. & Ifemeje, J.C. (2006). Trace metal levels in raw
and heat processed Nigerian staple foods from oil-producing areas of
Rivers and Bayelsa States. Journal of Applied Science & Environmental
Management, 10(3), 23-27.
Akinpelu, J.A. (1987). Relevance in Education. Inaugural Lecture, University of
Ibadan, delivered on April 19, 1983.
Akinyemi, K.O., Oladapo, O., Okwara, C.E., Ibe, C.C. & Fasure, K.A. (2005).
Screening of crude extracts of six medicinal plants used in South-West
Nigerian unorthodox medicine for anti-methicillin resistant
Staphylococcus aureus activity. BMC Complementary & Alternative
Medicine, 5, 6.
Amadi, B.A., Ayalogu, E.O. & Onyeike, E.N. (2011). Nutrient and anti-nutrient
composition of “Onunu” and “Mgbam” traditional foods of Ikwerre Ethnic
Nationality in South Southern Nigeria. Journal of Emerging Trends in
Engineering & Applied Sciences (JETEAS), 2(3), 374-378.
Amadi, B.A., Ayalogu, E.O. and Onyeike, E.N. (2012). Performance
characteristics and organ weight of rats fed ‘Onunu’ and ‘Mgbam’

110
 traditional diets of the Ikwerre people of Niger Delta, Nigeria. Continental
Journal of Food Science and Technology, 6(1), 13-20.
Amadi, B.A., Onyeike, E.N. & Ayalogu, E.O. (2011). Fatty and amino acid
composition of “Onunu” and “Mgbam” traditional diets of the Ikwerre
people of Nigeria. Continental Journal of Food Science & Technology, 5(1),
37-45.
Amadi, B.A., Onyeike, E.N. & Ayalogu, E.O. (2012). Mineral content and sensory
evaluation of “Onunu” and “Mgbam” traditional diet of the Ikwerre people
of Nigeria. Archives of Applied Science Research, 4(1), 330-335.
Anderson, J. & Barbara, B.D. (1995). The Nutrition Bible: A comprehensive, no-
nonsense guide to foods, nutrients, additives, preservatives, pollutants and
everything else we eat and drink. New York: William Morrow.
Andrew, P. (2012 May 21). An Entrepreneur Bankrolls a Genetically Engineered
Salmon. The New York Times. Accessed November 22, 2012, from
http://www.nytimes.com/2012/05/22/business/kakha-bendukidze-holds-
fate-of-gene-engineered-salmon.html?pagewanted=all
Antonios, T. & Mac Gregor, G.A. (1996). Salt – more adverse effects. Lancet, 347,
250-252.
Ayalogu, E.O., Ikewuchi, C.C., Onyeike, E.N. & Ikewuchi, J.C. (2011). Effects of an
aqueous leaf extract of Sansevieria senegambica Baker on plasma
biochemistry and haematological indices of salt-loaded rats. South African
Journal of Science, 107(11&12), 481-485.
Ayalogu, E.O., Onyeike, E.N. & Okaraonye, C.C. (2003). Evaluation of the
nutritional status of rats fed diets formulated from larvae of raphia palm
beetle (Oryctes rhinoceros) and weevil (Rhyncophorus pheonicis).
Nigerian Journal of Biochemistry & Molecular Biology, 18(1), 47-51.
Bababunmi, E.A., Uwaifo, A.O. & Bassir, O. (1977). Carcinogens contamination of
Nigerian foods. Proceedings of the International Congress on Toxicology,
Toronto.
Bagchi, D.B. (2006). Nutraceuticals and functional foods regulations in the
United States and around the world. Toxicology, 221(1), 1-3.
British Thyroid Foundation (2007). Goiter and its treatment. British Thyroid
Foundation. URL: http://www.patient.co.uk/health/goitre-(Thyroid-
Swelling).htm
Bussing, A., Stein, G.M., Herterich-Akinpelu, I. & Pfuller, U. (1999). Apoptosis-
associated generation of reactive oxygen intermediates and release of pro-
inflammatory cytokines in human lymphocytes and granulocytes by
extracts from the seeds of Acalypha wilkesiana. Journal of
Ethnopharmacology, 66(3), 301-309.

111
Butler, L.G. (1989). Effects of condensed tannin on animal nutrition. In: R.W.
Hemingway & J.J. Karchesy (Eds.), Chemistry and Significance of
Condensed Tannins (pp.391-402). New York: Plenum Press.
Canola Oil. Soyatech. Retrieved November 22, 2012 from
http://www.soyatech.com/canola_facts.htm
Carretero, O.A. & Oparil, S. (2000). Essential hypertension, Part 1: definition and
etiology. Circulation, 101(3), 329-335.
Chinenye, S. (2011). Experts advocate regular monitoring of blood glucose.
UNIPORT Weekly, 7(6), 3.
Chobanian, A.V., Bakris, G.L., Black, H.R., Cushman, W.C., Green, L.A., Izzo, J.L.
Jr., Jones, D.W., Materson, B.J., Oparil, S., Wright, J.T. Jr., Roccella, E.J.;
Joint National Committee on Prevention, Detection, Evaluation, and
Treatment of High Blood Pressure. National Heart, Lung, and Blood
Institute; National High Blood Pressure Education Program Coordinating
Committee. (2003). Seventh report of the Joint National Committee on
prevention, detection, evaluation and treatment of high blood pressure.
Hypertension, 42(6), 1206-1252.
Christman, S. (2004). Acalypha wilkesiana. Floridata.com LC, Florida.
http://www.floridata.com/ref/A/acal_wil.cfm
Consumers International-Home (2009). URL:
http://www.consumersinternational.org/ news-and-media/news.
Deeley, C.M., Gao, M., Hunter, R. & Ehlermann, D.A.E. (2006). The development
of food irradiation in the Asia Pacific, the Americas and Europe; tutorial
presented to the International Meeting on Radiation Processing, Kuala
Lumpur. URL:
http://www.doubleia.org/index.php?sectionid=43&parentid=
13&contentid=494
Doull, J. (2001). Recommended limits for occupational exposure to chemicals. In:
J. Doull, C.D. Klaassen & M.O. Arthur (Eds.), Casarett and Doull's
th
Toxicology: The Basic Science of Poisons, 6 Edn. New York: McGraw-Hill.
Eheazu, B.A. (1998). The right to learn: Relevance of Adult Education. Inaugural
Lecture Series Number 20, University of Port Harcourt, delivered on
September 24, 52pp.
Ekeke, G.I. (2000). The role of biochemistry in society. In: Biochemical Flash- A
publication of the National Association of Biochemistry Students,
University of Port Harcourt Chapter, 1(1), 8-9.
El-Mahmood, A.M., Doughari, J.H. & Chanji, F.J. (2008). Herbal uses of ring
worm plant (Senna alata). Science Research Essays, 3, 102-105.
Ekpechi, O.L. (1967). Pathogenesis of endemic goiter in Eastern Nigeria. British
Journal of Nutrition, 21, 537-545.

112
European Food Safety Authority. (2012). Genetically modified animals. Europe:
EFSA. URL: http://www.efsa.europe.eu/en/topic/gmanimals.htm
th
Evans, W.C. (2005). Trease and Evans Pharmacognosy, 15 Edn. India: Elsevier.
Fleming, S.E. (1981). A study of relationships between flatus potential and
carbohydrate distribution in legume seeds. Journal of Food Science, 46,
794-803.
Friends of the Earth International (2008). Who benefits from gm crops? The rise
in pesticide use.
http://www.foe.co.uk/resource/briefings/who_benefits.pdf
Gill, L.S. (1992). Ethnomedical uses of plants in Nigeria. Benin City: University of
Benin Press.
Grossarth-Maticek, R. & Ziegler, R. (2007). Prospective controlled cohort studies
on long term therapy of ovarian cancer patients with mistletoe (Viscum
album L.) extracts iscador. Arzneimittelforschung, 57, 665-678.
Grubesic, R.J., Vukevic, J., Kremer, D. & Vladimir-Knezevic, S. (2007). Flavonoid
content assay: Prevalidation and application on Plantago L. species. Acta
Chimiya Slovenia, 54, 397-406.
Hasler, C.M. (1998b). Scientific status summary, functional foods: their role in
disease prevention and health promotion. Food Technology, 52(11), 61-70.
Hasler.C.M. (1998a). A new look at an ancient concept. Chemistry & Industry, 3,
84-89.
Hauter, W. & Worth, M. (2008). Zapped! Irradiation and the death of food.
Washington, D.C.: Food & Water Watch Press.
Heldman, D.R. (2006). IFT and the Food Science Profession: President’s message.
Food Technology Magazine, October 2006, 60(10), URL:
http://www.ift.org/food-technology/past-issues/2006/october/columns/
presidents-message.aspx
Henry, C.J.K & Massey, D. (2001). Micronutrient changes during food processing
and storage. Crop Post Harvest Programme, 5, 1-4.
Hoffman, D. & Wynder, E.L. (1972). Cigarette smoking and carcinogenesis. In: I.
Schemeltz (Ed.), The Chemistry of Tobacco Smoke, (p.123). New York:
Plenum Press.
Houdebine, L.-M., (2009). Production of pharmeceutical by transgenic animals.
Comparative Immunology, Microbiology & Infectious Diseases, 32(2), 107–
121.
http://www.fda.gov/animalveterinary/developmentapprovalprocess/geneticengin
eering/geneticallyengineeredanimals/ucm113672.htm
Ibegbulem, C.O., Ayalogu, E.O. & Onyeike, E.N. (2006). Effect of consuming fish
caught from crude oil contaminated freshwater on the relative organ
weights and carcass lipid levels of rats. Bio-Research, 4(1), 63-66.

113
Ibeh, G.O., Onyeike, E.N. & Isodikiari, A.G. (2006). Protein levels in urine of
pregnant women in Rivers State, Nigeria. Journal of Applied &
Environmental Management, 10(3), 171-173.
Ikegwuonu, F.I. & Bassir, O. (1976).The toxicity of phytohaemagglutinins to
chicken embryos. Toxicology, 14, 139-141.
Ikewuchi, C.C., Ayalogu, E.O., Onyeike, E.N. & Ikewuchi, J.C. (2012). Effect of
aqueous extract of the leaves of Sansevieria liberica Gérôme and Labroy on
blood pressure indices and pulse rates of sub-chronic salt-loaded rats.
Journal of Natural Remedies, 12(1), 30-38.
Ikewuchi, C.C., Ikewuchi, J.C., Ayalogu, E.O. & Onyeike, E.N. (2010). Proximate
and phytochemical profile of Sansevieria liberica Gerome and Labroy.
Journal of Applied Science & Environmental Management, 14(2), 103-106.
Ikewuchi, C.C., Ikewuchi, J.C., Ayalogu, E.O. & Onyeike, E.N. (2011). Weight
reducing and hypocholesterolemic effect of aqueous leaf extract of
Sansevieria senegambica Baker on sub chronic salt-loaded rats:
Implication for the reduction of cardiovascular risk. Research Journal of
Pharmacy & Technology, 4(5), 725-729.
Ikewuchi, C.C., Ikewuchi, J.C., Onyeike, E.N. & Ayalogu, E.O. (2010). Effect of
Sansevieria liberica Gerome and Labroy on plasma chemistry and
haematological indices of salt-loaded rats. Research Journal of Science &
Technology, 2(5), 110-114.
Ikewuchi, J.C. (2012). Phytochemical studies and pharmacological effects of leaves
of Acalypha wilkesiana Muell Arg “Godsefiana” (Euphorbiaceae) and
Tridax procumbens Linn (Asteraceae) on Wistar albino rats. PhD
Dissertation, University of Port Harcourt, 464 pp.
Ikewuchi, J.C., Ayalogu, E.O., Onyeike, E.N. & Ikewuchi, C.C. (2011). Study on
the alkaloid, allicin, glycoside and saponin composition of the leaves of
Sansevieria liberica Gerome and Labroy by gas chromatography. Pacific
Journal of Science & Technology, 12(1), 367-373.
Ikewuchi, J.C., Ikewuchi, C.C., Onyeike, E.N. & Uwakwe, A.A. (2010). Nutritional
potential of the leaves of Acalypha wilkesiana “Godsefiana” Muell Arg.
Journal of Applied Science & Environmental Management, 14(3), 21-24.
Ikewuchi, J.C., Onyeike, E.N., Uwakwe, A.A. & Ikewuchi, C.C. (2011). Effect of
aqueous extract of the leaves of Tridax procumbens Linn on blood
pressure components and pulse rates of sub chronic salt-loaded rats.
Pacific Journal of Science & Technology, 12(1), 381-389.
Ikewuchi, J.C., Onyeike, E.N., Uwakwe, A.A. & Ikewuchi, C.C. (2011). Weight
reducing and hypocholesterolemic effects of aqueous extract of the leaves
of Tridax procumbens Linn on sub-chronic salt-loaded rats. International
Journal of Biological & Chemical Sciences, 5(2), 680-687.

114
Ikewuchi, J.C., Onyeike, E.N., Uwakwe, A.A. & Ikewuchi, C.C. (2011). Effect of
aqueous extract of the leaves of Acalypha wilkesiana “Godseffiana” Muell
Arg (Euphorbiaceae) on the hematology, plasma biochemistry and ocular
indices of oxidative stress in alloxan-induced diabetic rats. Journal of
Ethnopharmacology, 137, 1415-1424.
Ikewuchi, J.C., Onyeike, E.N., Uwakwe, A.A. & Ikewuchi, C.C. (2011). Effect of
aqueous extract of the leaves of Acalypha wilkesiana “Godseffiana” Muell
Arg on blood pressure components and pulse rates of salt-loaded rats.
Research Journal of Science & Technology, 3(5), 264-269.
Ikewuchi, J.C., Uwakwe, A.A., Onyeike, E.N. & Ikewuchi, C.C. (2011).
Hepatoprotective effect of an aqueous extract of the leaves of Acalypha
wilkesiana “Godseffiana” Muell Arg (Euphorbiaceae) against carbon
tetrachloride induced liver injury in rats. Experimental & Clinical Sciences
International Online Journal for Advances in Science (EXCLI), 10, 280-289.
Irvin, C.C. (1973). Interaction of chemical carcinogens with DNA. In: H. Bush
(Ed.), Methods in Cancer Research, 12, 189-224.
Irvine, F.R. (1961). Woody plants of Ghana with special reference to their uses.
London: Oxford University Press. pp. 178-183.
Jackson, D.A., Symons, R.H. & Berg, P. (1972). Biochemical method for inserting
new genetic information into DNA of Simian Virus 40: Circular SV40
DNA molecules containing lambda phage genes and the galactose operon
of Escherichia coli. Proceedings of the National Academy of Science, 69(10),
2904–2909.
James, C. (1996). Global review of the field testing and commercialization of
transgenic plants: 1986 to 1995. The International Service for the
acquisition of Agri-biotech Applications. Retrieved November 2012 from
http://www.isaaa.org/kc/Publications/pdfs/isaaabriefs/Briefs%201.pdf
James, C. (2011). ISAAA Brief 43, Global Status of Commercialized Biotech/GM
Crops: 2011. ISAAA Briefs. Ithaca, New York: International Service for the
Acquisition of Agri-biotech Applications (ISAAA). Retrieved November
2012 from
http://www.isaaa.org/resources/publications/briefs/43/executivesummar
y/default.asp
Jetté, M., Landry, F., Blümchen, G. (1987). Exercise hypertension in healthy
normotensive subjects. Implications, evaluation and interpretation. Herz,
12(2), 110-118.
Johnston, S.A. & Tang, D.C. (1994). Gene gun transfection of animal cells and
genetic immunization. Methods in Cell Biology, 43 Pt A, 353–365.
Kafuru, E. (1993, June 3). Mistletoe – an example of an all-purpose herb in herbal
remedies. Guardian Newspaper, p. 11.

115
Kakade, M.L., Rackis, J.J., McGhee, J.E. & Puski, G. (1974). Determination of
trypsin inhibitor activity of soy products: A collaborative analysis of an
improved procedure. Cereal Chemistry, 51, 376-382.
Kazmi, A. (2005, August 13). Scientists warn against fried foods at United Arab
Emirates University. UAE Health. Retrieved from
http://gulfnews.com/news/gulf/uae/health/scientists-warn-against-fried-
foods-1.297251
Kent, N.L. (1974). Technology of Cereals. Oxford, U.K.: Pergamon Press.
King, D. (2003). GM Science Review First Report Prepared by the UK GM Science
Review Panel, PG.
Kinsella, J.L. (1976). Functional properties of proteins in foods: A survey. In:
Critical Reviews in Food Science and Nutrition (T.L. Fluria, Ed.), 7, 219.
Klaus, D. (1987). Differential therapy of exercise in hypertension (in Greman).
Herz, 12(2), 146-155.
Kruizenga, H.M., de Vet, H.C. & Van Marissing, C.M. (2010). The SNAO(RC), an
easy traffic light system as a first step in the recognition of undernutrition
in residential care. Journal of Nutrition, Health & Aging, 14(2), 83-89.
Kume, T., Furutab, M., Todorikic, S., Uenoyamad, N. & Kobayashi, Y. (2009).
Status of food irradiation in the world. Radiation Physics & Chemistry,
78(3), 222-226.
Lai, L. et al. (2006). Generation of cloned transgenic pigs rich in omega-3 fatty
acids. Nature Biotechnology, 24(4), 435–436.
Leader, B., Baca, Q.J. & Golan, D.E. (2008). Protein therapeutics: a summary and
pharmacological classification. National Review of Drug Discovery, 7(1),
21–39.
Lederberg, J. & Tatum, E.L. (1946). Gene recombination in E. coli. Nature,
158(4016), 558.
Leikin, J.B. & Lipsky, M.S. (2003).American Medical Association Complete Medical
Encyclopedia. New York: Random House References.
Lomonosov, M.V. (1748). The role of biochemistry in society. In: Biochemical
Flash, 1(1), 8.
Mackenzie, D. (2008). How the humble potato could feed the world. New
Scientist No. 26672, 30-33.
Mayo Foundation for Medical Education and Research (2008). Secondary
hypertension. Retrieved May 10, 2010 from
http://www.mayoclinic.com/health/secondary-hypertension/DS01114
Mc Kenney, C. (2009, April 15). A brief history of nutrition. Prospectus News.
Retrieved from http://www.prospectusnews.com/news/a-brief-history-of-
nutrition-science-1.2114911#.UGnsg9V62uI

116
Melo, E.O., Canavessi, A.M.O., Franco, M.M. & Rumpf, R. (2007). Animal
transgenesis: state of the art and applications. Journal of Applied Genetics,
48(1), 47–61.
Mercola.com. Take control of your health. http://www.mercola.com/ Visited
February 10, 2007.
Meyer, J.P. (2006). Fried foods. In: Back to Health, Your Guide to Better Living.
Back to Health 7643, Cass St. Omaha, NE. URL: http://www.
chiropracticomaha.com/Newsletters/B2H_2006-11.pdf
Michelle, S. (2011 August 24). ConAgra sued over GMO ‘100% natural’ cooking
oils. Food Safety News. Accessed November 22, 2012, from
http://www.foodsafetynews.com/2011/08/conagra-sued-over-gmo-100-
natural-cooking-oils/
Midlleton, R. Jr., Kandaswami, C. & Theoharides, T.C. (2000). The effects of plant
flavonoids on mammalian cells: Implications for inflammation, heart
disease and cancer. Pharmacological Reviews, 52, 673-751.
Miller, J.A. & Miller, E.C. (1965). Natural and synthetic chemical carcinogens in
the etiology of cancer. Cancer Research, 25, 1295.
Miller, J.A. & Miller, E.C. (1971). Chemical carcinogenesis, mechanism and
approaches to its control. Journal of National Cancer Institute, 47, 5-14.
Monosson, E. (2006). Toxicology. In: J.C. Cutler & S. Draggan (Eds.), Encyclopedia
of Earth. Washington D.C.: Environmental Information Coalition,
Nutrition Council for Science and the Environment. Retrieved August 29,
2011, from http://www.eoearth.org/article/Toxicology
Montgomery, R.D. (1980). Cyanogens. In: I.E. Liener (Ed.), Toxic Constituents of
Plant Foodstuffs, (pp.143-160). New York: Academic Press.
Morlin. Z., Kertesz, M. & Kiss, A. (1979). The presence of 20-methylcholanthrene
in atmospheric air. Infectionskr Hygiene, 169(5 & 6), 446-455.
Mulinda, J.R. (2007). Goitre and its Treatment. British Thyroid Foundation.
(http://www.patient.co.uk/health/Goitre-(Thyroid-swelling).htm).
National Agricultural Statistics Service (2010). Acreage. Report of Agricultural
Statistics Board, U.S. Department of Agriculture. URL:
http://usda.mannlib.cornell.edu/usda/nass/Acre/2010s/2010/Acre-06-30-
2010.pdf
National Cottonseed Producers Association (2002). Twenty facts about
cottonseed oil. URL: http://www.cottonseed.com/publications/facts.asp
National Research Council (2004). Safety of genetically engineered foods:
Approaches to assessing unintended health effects. National Academy
Press.
Nduka, E.C. (2007). Statistics has it that …………… Inaugural Lecture Series
Number 57, University of Port Harcourt, delivered on November 22, 52pp.

117
Nelson, M. (2010). Drug treatment of elevated blood pressure. Australian
Prescriber, 33(4), 108-112.
Nicholas, A. (1810). Inventeur et humaniste (Inventor of canning process) by Jean-
Paul Barbier, Paris, 1994. Retrieved from http://www.appert-aina.com/
Nutrition.gov URL: http://www.nutrition.gov
Nwaichi, E.O. & Onyeike, E.N. (2010). Copper tolerance and accumulation by
Centrosema pubescen Benth and Mucuna pruriens Var pruriens. Archives
of Applied Research, 2(3), 238-247.
Nwaichi, E.O. & Onyeike, E.N. (2011). Assessment and characterization at green
remediation of crude oil contaminated soils. Annals of Biological
Research, 2(2), 502-511.
Nwaichi, E.O. & Onyeike, E.N. (2011). Interaction of selected minerals with
organic pollutants: Effects of phyto assisted bioremediation using Vigna
subterranean. Journal of Environmental & Analytical Toxicology, 1(2), 1-4.
Nwaichi, E.O., Onyeike, E.N. & Wegwu, M.O. (2010). Characterization and safety
evaluation of the impact of hydrocarbon contaminants on ecological
receptors. Bulletin of Environmental Contamination & Toxicology, 85, 199-
204.
Nwaichi, E.O., Onyeike, E.N. & Wegwu, M.O. (2010). Comparison of chicken
manure and urea fertilizers as potential soil amendments for enhanced
phytoextraction of heavy metals. Bioremediation Journal, 14(4), 180-188.
Nwaichi, E.O., Onyeike, E.N. & Wegwu, M.O. (2010). Performance and risk
assessment of Bambara beans grown on petroleum contaminated soil and
the biostimulation implications: African Journal of Environmental Science
& Technology, 4(4), 174-182.
Nwaichi, E.O., Onyeike, E.N. & Wegwu, M.O. (2010). Safety evaluation of the
impact of metal contaminants on ecological receptors. Annals of
Biological Research, 1(1), 191-198.
Nwaichi, E.O., Osuji, L.C. & Onyeike, E.N. (2011). Evaluation and
decontamination of crude oil polluted soils using Centrosema pubescen
Benth and amendment support options. International Journal of
Phytoremediation, 13(4), 373-382.
Nwaichi, E.O., Wegwu, M.O. & Onyeike, E.N. (2009). Phytoextracting cadmium
and copper using Mucuna pruriens. African Journal of Plant Science, 3(2),
277-282.
Nwosu, C.J. & Onyeike, E.N. (2009). Obesity and chronic diseases: A review of
the changing nutritional patterns in Nigeria. International Journal of
Biochemistry, 1(1), 64-69.
Oakenful, D. & Sidhu, G.S. (1989). Saponins. In: P.R. Cheeke (Ed.), Toxicants of
Plant Origin, Volume II (pp. 78-113). New York: Academic Press.

118
Obatomi, D.K., Bikomo, F.O., & Temple, V.J. (1994). Antidiabetic properties of
the African mistletoe in streptozotocin-induced diabetic rats. Journal of
Ethnopharmacology, 43, 13-17.
Onyeike, E.N. & Acheru, G.N. (2002). Chemical composition of selected Nigerian
oil seeds and physicochemical properties of the oil extracts. Food
Chemistry, 77(4), 431-437.
Onyeike, E.N. & Ayalogu, E.O. (1996). Protein losses in African yam bean seeds
soaked in various salt solutions. Delta Agriculturist, 3, 130-133.
Onyeike, E.N. & Ayalogu, E.O. (1999a). Functional properties of raw and heat
processed African yam bean seed flours. Journal of Agriculture,
Biotechnology & Environment, 1, 41-52.
Onyeike, E.N. & Ayalogu, E.O. (1999b). Trypsin inhibitor levels in marble-
coloured variety of African yam bean seeds as affected by extraction time,
dilution factors and heat treatment. Journal of Agriculture, Biotechnology
& Environment, 1, 33-40.
Onyeike, E.N. & Ehirim, F.C. (2001). Chemical and sensory evaluation of melon
fungus (Pleurotus tuber regium) and melon fungus cake. Nigerian Journal
of Biochemistry & Molecular Biology, 16(2), 77-81.
Onyeike, E.N. & Ikuru, P.I. (1998). Preliminary investigation of proximate
composition of heat processed cashew nut seed (Anacardium occidentale)
flours. Journal of Applied Science & Environmental Management, 1(1), 27-
30.
Onyeike, E.N. & Morris, P.I. (1996). Evaluation of the nutritional quality of a
weaning food from African yam bean – rice – prawn mixture. Delta
Agriculturist, 3, 134-137.
Onyeike, E.N. & Nkwuzor, N.F. (2006). Evaluation of the nutritional quality of
diets formulated from processed cashew nut seed (Anacardium
occidentale) flours. Scientia Africana, 5(1), 53-65.
Onyeike, E.N. & Nwideezia, N.D. (2001). Nutrient composition and levels of
some toxicants in three species of cocoyam tubers as affected by heat
treatments. Nigerian Journal of Biochemistry & Molecular Biology, 16(2),
123-127.
Onyeike, E.N. & Ogbuja, S.I. (1999). Physicochemical characteristics of soils and
rivers in some oil-producing areas of the Niger Delta under the influence
of crude oil spillage. Journal of Applied Science & Environmental
Management, 3, 23-28.
Onyeike, E.N. & Oguike, J.U. (2003). Influence of heat processing methods on
the nutrient composition and lipid characterization of groundnut
(Arachis hypogaea) seed pastes. Biokemistri, 15(1), 34-43.

119
Onyeike, E.N. & Olungwe, T. (1998). Functional properties of raw and heat
processed melon seed, dikatnut seed and cocoyam tuber flours. Nigerian
Journal of Science & Environment, 1(1), 91-100.
Onyeike, E.N. & Omubo-Dede, T.T. (2002). Effect of heat treatment on the
proximate composition, energy values and levels of some toxicants in the
African yam bean (Sphenostylis sternocarpa) seed varieties. Plant Food for
Human Nutrition, 57(3&4), 223-231.
Onyeike, E.N. & Onwuka, O. (1999). Chemical composition of some fermented
vegetable seeds used as soup condiments in Nigeria East of the Niger.
Global Journal of Pure & Applied Sciences, 5(3), 337-342.
Onyeike, E.N. & Uzogara, S.G. (2000). Effect of soaking in salt solutions on water
absorption, pH and cooking time of African yam bean seeds (Sphenostylis
sternocarpa Hochst Ex. A. Rich Harms). Global Journal of Pure and Applied
Sciences, 6(1), 67-73.
Onyeike, E.N. & Uzoka, U.N.J. (2006). Nutritional quality of foods formulated
from cowpea-millet-crayfish mixtures. Global Journal of Pure & Applied
Sciences, 12(4), 513-519.
Onyeike, E.N. (1982). Effect of habitat on the occurrence of carcinogenic
polycyclic aromatic hydrocarbons in Nigerian smoked fish samples. B.Sc.
Project, University of Port Harcourt, 63 pp.
Onyeike, E.N., Abbey, B.W. & Anosike, E.O. (1991). Kinetics of heat inactivation
of trypsin inhibitors from the African yam bean (Sphenostylis
sternocarpa). Food Chemistry, 40, 9-23.
Onyeike, E.N., Akaninwor, J.O. & Ifemeje, J.C. (2008).Effect of heat processing
on the proximate composition and energy values of selected Nigerian
staple foods from oil-producing areas of Niger Delta. Biokemistri, 20(1), 1-
9.
Onyeike, E.N., Amadi, R.C. & Nwosu.C.J. (2002). Effect of ripening on the levels
of nutrients and antinutritional factors in Mexican avocado pear (Persea
americana). Nigerian Journal of Biochemistry & Molecular Biology, 17(2),
79-82.
Onyeike, E.N., Ayalogu, E.O. & Abbey, B.W. (1998). Nutritional status of rats fed
diets based upon soaked African yam bean seed flours. Journal of
Innovation in Life Sciences, 3, 34-41.
Onyeike, E.N., Ayalogu, E.O. & Abbey, B.W. (1999). Nutritional status of rats fed
diets based on different heat treated African yam bean seed flours. Global
Journal of Pure & Applied Sciences, 5(2), 207-214.
Onyeike, E.N., Ayalogu, E.O. & Ibegbulem, C.O. (2000). Evaluation of the
nutritional value of some crude oil polluted freshwater fishes. Global
Journal of Pure & Applied Sciences, 6(2), 227-233.

120
Onyeike, E.N., Ayalogu, E.O. & Okaraonye, C.C. (2005). Nutritive value of the
larvae of raphia palm beetle (Oryctes rhinoceros) and weevil
(Rhyncophorus pheonicis). Journal of the Science of Food & Agriculture,
85(11), 1822-1828.
Onyeike, E.N., Ayalogu, E.O. & Uzogara, S.G. (1995). Influence of heat
processing of African yam bean seed (Sphenostylis sternocarpa) flour on
the growth and organ weights of rats. Plant Foods for Human Nutrition,
48, 85-93.
Onyeike, E.N., Ihugba, A.C. & George, C. (2003). Influence of heat processing on
the nutrient composition of vegetable leaves consumed in Nigeria. Plant
Foods for Human Nutrition, 58(3), 1-11.
Onyeike, E.N., Ikewuchi, J.C., Ikewuchi, C.C. & Uwakwe, A.A.
(2010).Quantitative high performance liquid chromatography analysis of
simple terpenes, carotenoids, phytosterols and flavonoids in the leaves of
Acalypha wilkesiana Muell Arg. Pacific Journal of Science & Technology,
11(2), 480-487.
Onyeike, E.N., Nwinuka, N.M. & Enwere, D.I. (2001). Proximate composition,
energy content and physicochemical properties of Nigerian edible fats
and oils. Biokemistri, 11(2), 113-122.
Onyeike, E.N., Ogbuja, S.I. & Nwinuka, N.M. (2002). Inorganic ion levels of soils
and streams in some areas of Ogoni land, Nigeria as affected by crude oil
spillage. Environmental Monitoring & Assessment, 73(2), 191-205.
Onyeike, E.N., Olungwe, T. & Uwakwe, A.A. (1995).Effect of heat processing and
defatting on the proximate composition of some Nigerian local soup
thickeners. Food Chemistry, 53(2), 173-175.
Oppenheimer, B.S. & Fishberg, A.M. (1928).Hypertensive encephalopathy.
Archives of Internal Medicine, 41, 264.
Orisakwe, O. (2011). What is eating us up is what we eat. UNIPORT Weekly, 3(9),
1-8.
Osagie, A.U. (1998). Antinutritional factors. In: A.U. Osagie & O.U. Eka (Eds.),
Nutritional Quality of Plant Foods (pp. 221-244). Benin City: AMBIK Press.
Osuji, J.O., Onyeike, E.N. & Nwachukwu, A.S. (1998). Histochemical localization
of tannins in ripe and unripe fruits of Musa L. (Muscaceae). Journal of
Innovations in Life Sciences, 3, 42-47.
Osuntokun, B.O. (1972). Chronic cyanide neurotoxicity and neuropathy in
Nigerians. Plant Foods for Human Nutrition, 2, 215-266.
Osuntokun, B.O. (1973). Ataxic neuropathy associated with high cassava diets in
West Africa. In: B.L. Nestel & R. Macintyre (Eds.), Chronic Cassava
Toxicity, (p. 127). Ottawa, Cannada: IDRC.
Palatini, P. (1999). Need for a revision of the normal limits of resting heart rate.
Hypertension, 33(2), 622-625.

121
Panesar, P. et al (2010). Enzymes in Food Processing: Fundamentals and Potential
Applications, Chapter 10, I K International Publishing House.
Papadakis, M.A. & McPhee, S.J. (2008).Current Medical Diagnosis and Treatment.
McGraw-Hill Professional.
Patrick-Iwuanyanwu, K.C., Onyeike, E.N. & Dar, A. (2011). Anti-inflammatory
effect of crude methanolic extract and fractions of ring worm plant Senna
alata (L. Roxb) leaves from Nigeria. Der Pharmacia Sinica, 2(4), 9-16.
Patrick-Iwuanyanwu, K.C., Onyeike, E.N. & Wegwu, M.O. (2010). Anti-
inflammatory effect of crude methanolic extract and fractions of African
mistletoe, Tapinanthus banwensis (Engl. & K. Krause) on Wistar albino
rats. Der Pharmacia Lettre, 2(6), 76-83.
Patrick-Iwuanyanwu, K.C., Onyeike, E.N. & Wegwu, M.O. (2010).
Hepatoprotective effects of methanolic extract and fractions of African
mistletoe, Tapinanthus banwensis (Engl. & K. Krause) from Nigeria.
Experimental & Clinical Sciences International Online Journal for Advances
in Science (EXCLI), 9, 187-194.
Pauling, L. (1986). How to live longer and feel better. New York: Avon Books Inc.
Pierdomenico, S.D., Di Nicola, M., Esposito, A.L., Di Mascio, R., Ballone, E.,
Lapenna, D. & Cuccurullo, F. (2009). Prognostic value of different indices
of blood pressure variability in hypertensive patients. American Journal of
Hypertension, 22(8), 842-847.
Plaa, G.L. (2007). Introduction to Toxicology: Occupational and Environmental.
th
In: B.G. Katzung (Ed.), Basic and Clinical Pharmacology 10 Edn.
International edition, (pp. 934-944). Singapore: McGraw Hill Coy Inc.
Pott, P. (1775). Chirurgical Observations relative to the cataract, the polypus of the
nose, the cancer of the scrotum, the different kinds of ruptures, and the
mortification of the toes and feet. London: Hawes, Clarke & Collins.
Rand, G.M. & Petrocelli, S.R. (1985). Fundamentals of Aquatic Toxicology:
Methods and Applications. Washington: Hemisphere Publishing.
Reddy, N.R. & Pierson, M.D. (1994). Reduction in antinutritional and toxic
components in plant foods by fermentation. Food Research International,
27, 281-290.
Rodriguez-Cruz, E. & Ettinger, L.M. (2009). Hypertension. e-Medicine Pediatrics:
Cardiac Disease and Critical Care Medicine. Medscape. Retrieved June 16,
2009.
Ronald, P. & McWilliams, J. (2010 May 14). Genetically Engineered Distortions.
The New York Times. Retrieved November 22, 2012 from
http://www.nytimes.com/2010/05/15/opinion/15ronald.html?_r=2&ref=opi
nion
Salabdeen, H.M., Yemitan, O.K. & Alada, A.R.A. (2004). Effect of aqueous leaf
extract of Tridax procumbens on blood pressure and heart rate in rats.

122
 African Journal of Biomedical Research, 7, 27-29.
Sasaki, E., Suemizu, H., Shimada, A., Hanazawa, K., Oiwa, R., Kamioka, M.,
Tomioka, I., Sotomaru, Y., Hirakawa, R., Eto, T., Shiozawa, S., Maeda, T.,
Ito, M., Ito, R., Kito, C., Yagihashi, C., Kawai, K., Miyoshi, H., Tanioka, Y.,
Tamaoki, N., Habu, S., Okano, H. & Nomura, T. (2009). Generation of
transgenic non-human primates with germline transmission. Nature, 459,
(7246), 523–527.
Schatten, G. & Mitalipov, S. (2009). Developmental biology: Transgenic primate
offspring. Nature, 459(7246), 515–516.
Soetan, K.O. (2008). Pharmacological and other beneficial effects of
antinutritional factors in plants: A review. African Journal of
Biotechnology, 7, 4713-4721.
Soyatech.com. (2012). Canola Facts. Accessed November 22, 2012, from
http://www.soyatech.com/canola_facts.htm
Stevenson, H. (2011). Scientists use human genes in animals, so cows produce
human-like milk—or do they? USA: http://www.gaia-
health.com/articles401/000433-human-genes-cows-produce-human-
milk.shtml/
Taraphdar, A.K., Roy, M. & Bhattacharya, R.K. (2001). Natural products as
inducers of apoptosis: Implications for cancer therapy and prevention.
Current Science, 80(11), 1387-1396.
The Nobel Prize in Chemistry 2008. The Official Web Site of the Nobel
Foundation. Retrieved November 22, 2012 from
http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2008/press.
html
United States Environmental Protection Agency (n.d.). Whole Effluent Toxicity.
Retrieved from http://water.epa.gov/scitech/methods/cwa/wet/
USDA (2008). ARS National Genetic Resource Programme, Germplasm Resources
Information Network (GRIN), Beltsville.
Uwakwe, A.A. & Onyeike, E.N. (2003). Effect of nicotinic acid on haemoglobin –
S (HbS) gelation and osmotic fragility of HbS erythrocytes. Global Journal
of Medical Sciences, 2(1), 59-63.
Uwakwe, A.A., Onyeike, E.N. & Ohiri, R.C. (2012). pH variations and lipase
activities of crude oil bioremediated agricultural soil. International
Journal of Current Research, 4(08), 034-037.
Valdes-Biles, P. & Ziobro, G.C. (2007). Regulatory action criteria for filth and
other extraneous materials IV: Visual detection of hair in food. Regulatory
Toxicology & Pharmacology, 32(1), 73-77.
Wagner, J.R., Becker, R., Gumbmann, M.R. & Olson, A.C. (1976). Hydrogen
production in the rat following ingestion of raffinose, starchyose and
oligosaccharide-free bean residue. Journal of Nutrition, 106, 466-470.

123
Walsh, G. (2005). Therapeutic insulins and their large-scale manufacture. Applied
Microbiology & Biotechnology, 67(2), 151–159.
Wanucha, G. (2009). Two happy clams: The friendship that forged food science.
Food Technology. Retrieved from http://scopeweb.mit.edu/ ?p=216
th
Wardlaw, G.M. (1999). Perspectives in Nutrition, 4 Edn. London: McGraw-Hill.
Wegwu, M.O. & Onyeike, E.N. (2006). Growth performance and proximate
profile of Telferia occidentalis Hook F. (Cucurbitaceae) grown in crude
oil-polluted soil. Remediation (The Journal of Environmental Cleanup
Costs, Technologies & Techniques), 16(2), 99-111.
Weisburger, J.H., Yamamoto, R.S., Williams, G.H., Granthan, P.H., Matsushima,
T. & Weisburger, E.K. (1972). The sulphate ester of N-hydroxy-2-fluorenyl
acetamide as key ultimate hepatocarcinogen in the rat. Cancer Research,
32, 491-500.
th
Whitney, E. & Sharon, R. (2005). Understanding Nutrition, 10 Edn. Thomson-
Wadsworth Publishing.
Wikipedia (2009). Food Science. Retrieved December 21, 2009 from
http://en.wikipedia.org/wiki/Food_science
Wikipedia (2010). Essential nutrients. Retrieved from http://en.wikipedia.org/
Essential_nutrients
Wikipedia (2010). Mango. Retrieved December 10, 2010 from
http://en.wikipedia.org/wiki/Mango
Wikipedia (2010). Obesity. Retrieved 2011 from
http://en.wikipedia.org/wiki/obesity.
Wikipedia (2011). In vitro toxicology. Retrieved August 17 2011, from
http://en.wikipedia.org/wiki/in_vitro_toxicology
Wikipedia (2012). Genetically modified organism. Retrieved November 2012 from
http://en.wikipedia.org/wiki/Genetically_modified_organism
Wohler, F. (1828). Laboratory synthesis of urea. In: Biochemical Flash, 1(1), 8.
Wolf, G. (1952). Chemical Induction of Cancer. London: Cassel and Company
Limited.
Wongsrikeao, P., Saenz, D., Rinkoski, T., Otoi, T. & Poeschla, E. (2011). Antiviral
restriction factor transgenesis in the domestic cat. Nature Methods, 8(10),
853–859.
Wood, O.B. & Bruhn, C.M. (2000). Position of the American Dietetic Association:
Food irradiation. Journal of the American Dietetic Association, 100(2),
246-253.
Zyga, L. (2010). Scientist bred goats that produce spider silk. URL:
http://phys.org/news194539934.html/

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 CITATION ON

PROFESSOR EUGENE NWAOGWUGWU ONYEIKE.

B.Sc (UPH), PGDE (UNN), M.Sc, Ph.D (UPH), MNSBMB.

Introduction
Vice-Chancellor Sir, I feel honoured and privileged to be nominated as
th
University Orator to introduce Professor E.N. Onyeike, the 99 Inaugural
Lecturer of the University of Port Harcourt, Choba, Rivers State, Nigeria.
Prof. Onyeike is a distinguished Teacher and accomplished Research
Biochemist, an Academic Leader, a Mentor and a Great Scientist, who, on
account of his widely published research findings is an internationally
recognized Scholar.
th
Professor E.N. Onyeike was born on 10 December, 1955 at
Kauranamoda in the present Zamfara State, North West, Nigeria into the
family of a staff of the Nigerian Railway Corporation, Ezinna Paul
Nwaogwugwu Onyeike (in memorian) of Oparachi Mbaukwu Ihitte, and
Ezinne (Mrs) Sussana Onuawuchi Onyeike (Nee Abosi) (in memorian) of
Umunagbor Amagbor Ihitte, both in Ezinihitte Mbaise Local
Government Area of Imo State, Nigeria. He is the third child and second
son in a family of initially ten children (four girls and six boys), but now
three women and four men. His parents qualified and took the
traditional title of “Igbu Ewu Ukwu” (killing of goat for the waist title).

Education:
From Kauranamoda, Professor E.N. Onyeike returned to Eastern Nigeria
and started his primary education at the Local Authority School (now
Community Primary School) Oparachi, Mbaukwu Ihitte in Infant 1

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(1959), Infant 2 (1960) and Standards 1-3 (1961-1963). In 1964, the
Elementary School System commenced, and he was in Elementary 5, and
so, took his First School Leaving Certificate (FSLC) Examination in 1965.
He passed the competitive secondary school entrance examination in
1966, but did not go to the College between 1966 and 1971 (for 6 years)
due to the effect of the crisis in the North (1966) and subsequent
outbreak of the Nigerian/Biafran civil war (1967-1970) which he painfully
th
experienced. With the end of the war on 12 January, 1970, he could not
also enter the Secondary School that year for lack of school fees, as his
father, who worked with the Nigerian Railway Corporation for 35 years
returned from Kauranamoda to Mbaise in 1969 with only his head, and
losing all his property and investments in the North for which the
Onyeike family was among the families during the war that were tagged
“Ndi jiri isi ha lo” (those who came back with their heads).
In 1971, Prof. Onyeike followed his elder sister Mrs. Joy E.
Onuoha and her husband Mr. Joseph F.N. Onuoha to Ndiufu Achara
Ikwo in Abakaliki, where he re-took the FSLC examination and the East
Central State Common Entrance Examination into Secondary Schools. In
1972, he was admitted into Boys Secondary School (now Ezza High
School), Ezzikwo in Abakaliki and he obtained his WASC (Division 2) in
1976.
In Class 1, he became enlisted as one of the best first eleven
players of the Football Team, and was later the Games and Sports
Prefect/Football Captain of Ezzikwo High School that beat many
Secondary and Technical Schools in the then Abakaliki Zone. Prof.
Onyeike was also one of the best four students in his class from Year 1-5.
Others are Arc. Zachaeus O. Ijeoma (Managing Director, Maurij-Zakij
(Nig.) Ltd, Architects, Builders and Quantity Surveyors at
Rumuokwurusi, Port Harcourt), Dr. Hilary N. Ezeh (Senior Lecturer in
Geology, Ebonyi State University, Abakaliki, who is currently being
assessed for promotion to the rank of Professor) and Mr. Michael A. Uzor
(Director-General, Federal Information Centre, Awka, Anambra State).
Ezzikwo High School Abakaliki expected Prof. Onyeike in Division 1 with
Distinction in WASC examination which he had maintained over the
years and in MOCK examination, but he could not achieve that because
the Prefects including Prof. Onyeike were detained in Police custody

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from where they were writing WAEC examinations due to violent and
destructive riot organized and executed by Year 4 students who called
themselves the “Mao Mao” Group without the knowledge of the end
victims (the prefects) who were punished by the School Administration
for the offence they did not commit - an action which the Administration
of Mr. P.N.O. Ezeunu as Principal later regretted when they learnt about
the real culprits that rioted. The effect, which Prof. Onyeike regrets was
the poor WAEC result of Ezzikwo High School that year (Division 1 with
Distinction = 0; Division 1 = 1; Division 2 = 6; Division 3 = 8; Statement of
Result (SR) = 65 candidates).
In October 1978, he gained admission into four higher
institutions including University of Port Harcourt and opted for the
2
latter, where he graduated with a B.Sc (Hons) Biochemistry (2 ) in 1982.
Again, Prof. Onyeike was one of the second set of graduating students of
the University of Port Harcourt when students were used as experimental
guinea pigs. Out of about 60 students admitted into the Biochemistry
programme of the former School of Chemical Sciences, Uniport in 1978,
1 2 rd
only 13 graduated in 1982 with one candidate in 2 , eleven 2 and one 3
Class.
In 1985, he was admitted into the Postgraduate programme of
the University of Nigeria, Nsukka where he obtained the PGD in
Education (Credit) in 1986 that distinguishes him today as a Teacher.
Back to his Alma mater later in December 1986, he enrolled for an M.Sc
programme which was deferred from 1985 to 1986, and was one of the 3
out of 10 candidates enrolled for the programme that successfully
defended the M.Sc Thesis in 1988. The zeal to pursue a terminal degree
programme was occasioned by his ability to obtain at the M.Sc level, the
mandatory CGPA of 4.00 and above on a 5.00 point scale. Following his
excellent performance at Ph.D Admission Interview, he was admitted for
the programme, and he successfully defended his Doctoral Dissertation
rd
on 3 February, 1993.

Working Experience
Prof. E.N. Onyeike taught in Primary Schools as an Auxillary Teacher in
the Imo State School System in 1977 and 1978 before he gained admission
into the University of Port Harcourt as an undergraduate in October,

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1978. He taught at Government Secondary School, Lemu, Niger State
during his NYSC programme (1982-1983). From September 1983 to
October 1991, Prof. Onyeike taught as Senior Mathematics and Chemistry
Teacher in many secondary schools in Anambra and Imo States, and was
at a time Acting Vice-Principal, Ahiazu Secondary School, Lude Ahiara,
Mbaise. In the various secondary schools, he was also the Head of
Science Department among other responsibilities. During his M.Sc and
Ph.D programmes, he was for 5 years (1987-1991), a part-time Laboratory
Demonstrator and Teaching Assistant. He was a Senior Master I awaiting
promotion to the Principal Cadre when he joined Uniport in November
1991 as an Assistant Lecturer in Biochemistry on a salary that was about
48% less than what he was earning in the secondary school. Professor
Onyeike consistently rose through the ranks to become Lecturer II on
review of appointment (1993), Lecturer I (1996), Senior Lecturer (1999),
Associate Professor (2003) and attained the rank of full Professor of
th
Biochemistry with effect from 19 March, 2007; a chair he occupies till
date.

Professional Activities
The professional activities of Professor E.N. Onyeike include
(i) National Treasurer, Nigerian Society of Biochemistry and
Molecular Biology (NSBMB) from 2003 to 2007.
(ii) Associate Editor and Member of Editorial Board of
(a) Global Journal of Pure and Applied Sciences (1999 till date)
(b) Scientia Africana – An International Journal of Pure and
th
Applied Sciences (2001 to 20 February, 2011).
(c) Global Journal of Medical Sciences (2007 till date).
(iii) Editor, Book of Abstracts of the First South East Zonal
Conference of the NSBMB held in Uniport in June, 2002.
(iv) South East and South South Zonal Co-ordinator of NSBMB
(2007-2011).
(v) Editor, Scientia Africana (2011 till date).
(vi) Editor, Research Techniques in Biological and Chemical Sciences
(ISBN 978-8020-84-4). Springfield Publishers Limited, Owerri,
412pp. This is an authoritative text contributed by 33 scientists

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 spread across nine tertiary institutions in Nigeria, and used in
many Nigerian Universities.
University/Public Service
Vice-Chancellor Sir, Professor E.N. Onyeike has served as External
Examiner for the B.Sc, M.Sc and Ph.D degrees and as External Assessor of
candidates for professorial positions in many Nigerian Universities
including the Rivers State University of Science and Technology, Nkpolu
Port Harcourt; Imo State University, Owerri; Ebonyi State University,
Abakaliki; Michael Okpara University of Agriculture, Umuahia;
University of Nigeria, Nsukka; University of Benin, Benin City; Federal
University of Technology, Owerri and Abia State University, Uturu.
Records show that he has till date successfully assessed two candidates
for professorial positions, and has examined a total of 5 Ph.D
dissertations, 36 M.Sc theses and 624 B.Sc research projects in
Biochemistry and Biochemistry-related area of Environmental
Management.

Professor Onyeike has served the University of Port Harcourt in various

capacities as
 Assistant Examination Officer, Faculty of Science (1996-1999).
 Member, Department of Biochemistry Committee on Direct
Teaching and Laboratory Cost, DTLC (2004-date).

rd th
Member of Senate (3 January 2006 – 5 January, 2008).
 Member, Senate Appeals Committee on Certificate Verification
st th
(21 April, 2006 – 28 February, 2010).
 Senate Representative on the Board of University Demonstration
Primary School, UDPS (2006-2008).
 Member, Board of Basic Studies Unit (2006-2008).
 Permanent Member of Senate of the University of Port Harcourt
th
(19 March, 2007 till date).
 Chairman, Senate Appeals Committee on Certificate Verification
st
(ACCV) (1 March, 2010 until further notice).
 Dean, Faculty of Science Nominee at oral M.Sc and Ph.D
examinations (2007 till date).

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 Chairman, International Foundation for Science (IFS) Equipment
and Project Monitoring and Evaluation Sub-Committee,
University of Port Harcourt (2009 till date).
 Patron, Purple House, UDPS (2009-2011).
 Chairman, Committee on Admission of Students/Employment of
Staff, Department of Biochemistry (2010 till date).
 Chairman, Postgraduate Studies Committee, Department of
Biochemistry (2011 till date).
 Senior Consultant to the Committee on Review, Production and
th
Sale of the Department of Biochemistry Practical Manual (16
April, 2012 until further notice).
 Member, Research Ethics Committee, University of Port
rd
Harcourt (3 May, 2012 until further notice).

In this University, Professor Onyeike is a member of the Boards of the: (i)

Department of Biochemistry (ii) Faculty of Science (iii) Faculty of Basic
Medical Sciences (iv) College of Health Sciences Academic Board, (v)
Member of Faculty of Science Graduate Studies Committee, and (vi)
Member, Faculty of Science Appointments and Promotions Committee
(Academic).

Administrative Experience
Prof. Onyeike has served as Departmental Co-ordinator of Students’
Industrial Work Experience Scheme (1992-1999); Undergraduate and
Postgraduate Seminar Co-ordinator (1999-2004); Secretary to Group G of
Strategic Planning Workshop organized by the Strategic Planning
Committee of Uniport in April 2003; Chairman, Departmental Welfare
Committee (2000-2006); Welfare Officer/Chairman Welfare Committee,
Academic Staff Union of Universities, (ASUU) University of Port
Harcourt Branch (2002-2004).
Professor E.N. Onyeike was Acting Head, Department of
Biochemistry, Faculty of Science, Uniport (2006-2008). During his
Headship, the Department recorded tremendous achievements in quality
teaching, research and community service, had full programme
accreditation by the National Universities Commission (NUC),
improvement in infrastructure, increase in academic staff strength from

130
the long standing 14 to 25. Prof. Onyeike was adjudged one of the best
and lucky Heads of Departments as he also had at that time on his staff
list among others, Emeritus Prof. Emmanuel .O. Anosike, FAS (the first
University Valedictorian); Prof. Gabriel .I. Ekeke, FAS (now Late) (the
Biochemist who formulated “Ciklavit” endorsed by the World Health
Organization and produced commercially by Neimeth Pharmaceutical
Company for the management of sickle cell disease), Prof. Edward .O.
Ayalogu FNSBMB (the Deputy Vice-Chancellor - Administration) and
Prof (Mrs.) Bene W. Abbey (Dean, School of Graduate Studies), but today
she is the Deputy Vice-Chancellor (Research and Development),
University of Port Harcourt.

Membership of Professional Bodies

Our masquerade today is a member of the following bodies among others
 Nigerian Society of Biochemistry and Molecular Biology
(NSBMB).
 Nigerian Society for Experimental Biology (NISEB).
 Federation of African Societies of Biochemistry and Molecular
Biology (FASBMB).

Academic Leadership
Prof. Onyeike has for many years (1991 till date) taught courses to both
undergraduate and postgraduate students in Biochemistry Department
and in the Faculties of Science, Agriculture, Pharmaceutical Sciences,
Basic Medical Sciences and the College of Health Sciences, distinguishing
himself as an outstanding professional teacher and a mentor to many
younger academic and professional colleagues. He has shown leadership
in teaching and research activities, and has already supervised more than
120 B.Sc Projects, 20 M.Sc Theses and 6 Ph.D Dissertations of candidates
whom he has also mentored, and can therefore be seen to have
successfully replicated himself academically. The Ph.D candidates he has
produced are Dr. Emmanuel N. Agomuo, Dr. Eucharia O. Nwaichi, Dr.
Kingsley C. Patrick-Iwuanyanwu, Dr. (Mrs.) Catherine C. Ikewuchi (nee
Okaraonye), Dr. Benjamin A. Amadi and Dr. Jude C. Ikewuchi. Each of
them scored ‘A’ grade in the defense of his/her dissertation, attesting to
Prof. Onyeike’s dexterity in research design and execution, and in editing

131
of his students work before they are presented for final defence.
Currently, he is supervising 5 Ph.D and 8 M.Sc candidates among others.

Research Publications
Vice-Chancellor Sir, research is part of Professor Onyeike’s life, and he
has published widely, and the publications which started in foreign
journals are highly commendable. From 1991 till date, this productive
Research Biochemist has to his credit, a total of 68 articles published in
local, international and foreign journals. He has published 1 book which
he edited, 10 chapters in refereed books and has presented 26 papers at
local and international conferences. In most of his foreign publications,
he received letters of commendation from organizations, one of which
was from American Journal Experts – An Association of Ph.D, Graduate
Students from America’s Top 10 Research Universities in 2006.

Current Areas of Research Interest

With an array of his current Ph.D and M.Sc supervisees at various levels
of their works, Professor Onyeike is actively involved in research in
Nutritional Biochemistry and Toxicology, Environmental Biochemistry
and Pharmacological Biochemistry.
Part of on-going and future research include:
(i) Studies on the effect of processing on the amino acid profile,
minerals, vitamins and fatty acid composition of selected
indigenous foods in the Niger Delta, Nigeria.
(ii) Formulation and industrial production of ENOLAC – a conceived
infant weaning formula from available raw materials in Nigeria.

Listing
th
Professor E.N. Onyeike is listed in the 1999 16 Edition of “Marquis
Who’s Who in the World,” a publication which is limited to those
individuals who have demonstrated outstanding achievement in their
own fields of endeavour, and have hence made significant contribution
to the betterment of contemporary society.

Awards/Honours
Our Inaugural Lecturer has received the following awards and honours:

132
 National Association of Biochemistry Students (Uniport Branch)
th
Honorary Patron Certificate Award dated 15 November, 1997, in
recognition of his remarkable and invaluable contributions in
the human struggle towards a better living.
 Recipient of the 2002 Global Journal Award of Certificate of
Commitment to the growth, sustenance and maintenance of
high quality of Global Journal through prompt reviews of
manuscripts and promotion of the Journal.
 National Association of Biochemistry Students, Imo State
nd
University, Owerri, Certificate Award dated 2 June, 2011, in
recognition of his meritorious service as The Most Outstanding
External Examiner in the Department of Biochemistry, Imo State
University, Owerri.
 Procurement, Installation, Service, Maintenance and Use of
Scientific Equipment (PRISM) Certificate of Participation Award
in On-Site Training Programme, PRISM Scientific Institutions in
Nigeria and Madagascar organized by the International
th
Foundation for Science (IFS), NIPRD, Abuja Nigeria (6
th
November to 16 December, 2011).

Private Life
Professor E.N. Onyeike is a Christian of the Roman Catholic Faith. He is
happily married to Dr. (Mrs) Victoria Chinasa Onyeike (Nee Nwosu) – a
Senior Lecturer in the Department of Educational Management, Faculty
of Education, Uniport; a God-given help mate and the most beautiful
wife, Prof. Onyeike’s eyes can see – beauty in outlook, in character and
mind/heart. They are blessed with three children Chidinma,
Nzubechukwu and Nneoma. Outside the University, Prof. Onyeike has
participated in, and contributed significantly to the development of his
community at home. He is a member of (i) Umuokpueze Family
Association, Oparachi; (ii) Udokamma Age Grade, Oparachi Ihitte which
he formed in 1979; (iii) Mbaukwu Ihitte Development Union Federated,
(iv) Ihitte Development Union (IDU), Port Harcourt Branch; (v)
Friendship Train Mbaise; and (vi) Oganihu Mbaise, Port Harcourt. At
present, he is Chairman Education Committee, Oganihu Mbaise, Port

133
Harcourt. He is current Chairman, Mbaise Senior Staff Association,
University of Port Harcourt.

Hobbies
Prof. Onyeike takes delight in designing and conducting research
activities, travelling to places and in listening to good music. He loves
soccer which he played well in the early 1970’s in the then East Central
State.
Vice-Chancellor Sir, distinguished audience; I present to you an
accomplished Academic, a worthy Alumnus of the University of Port
Harcourt, a kind-hearted and Focused Teacher a principled man of
impeccable integrity who is firm in what he believes to be the right thing,
a Research Biochemist and Scholar of International repute, an
embodiment of academic excellence, a Mentor and a Role Model. I
present to you a Gentleman and Sportsman par excellence, a Seasoned
Administrator, a loving Husband and good family man, a peace maker
and fearless crusader for quality control and assurance.
Distinguished Ladies and Gentlemen, please join me to welcome
th
Professor Eugene Nwaogwugwu Onyeike to deliver the 99 Inaugural
Lecture of the University of Port Harcourt.

Professor Augustine A. Uwakwe

(University Orator)

Appendices

Plates 16 -36 Food samples, plant materials and sawdust/poultry

manure
which have been investivated.

134

Gourd containing the seeds Leaves

 Plate 16. Fluted pumpkin (Telfairia occidentalis)

Plate 17. Avocado pear (Persea americana)

African yam bean Pod African yam bean Seeds African yam bean Seeds
(Marble variety) (Miiky variety)
Plate 18. African yam bean (Sphenostylis stenocarpa) Varieties

Crude Oil Polluted Fishes

Unpolluted Fishes 135

Plate 19: Crude oil polluted and unpolluted fishes

Adult
Larvae
Plate 20 a Oil palm weevil (Rynchophorus phoenicis)

Adult weevil

Adult Larvae

Plate 20 b Oil palm beetle (Oryctes rhinoceros)

Larvae
Adult beetle
Cashew Fruits Roasted Cashew nuts Salted Cashew nuts
(Anacardium occidentale)

Plate 21 Cashew Fruits and processed Cashew nuts

136
 Seeds Leaves and flowers

Plate 22. Mucuna bean (Mucuna pruriens)

Leaves Brown variety White variety

Plate 23. Bambara groundnut (Vigna subterranean)

Brown variety

Plate 24. Ring worm plant (Senna alata (L.) Roxb.)

137
 Plate 25. African Mistletoe (Tapinanthus bangwensis)

Acalypha wilkesiana Muell Arg (Acalypha) Tridax procumbens L. (Coat buttons)

Plate 26

138
 Sansevieria liberica Gerome and Labroy (Sansevieria)

Sanseviera senegambica Baker (Sansevieria)

Plate 27

Plate 28. Cocoyam (Colocasia esculenta)

139
 UnRipe Ripe

Banana (Musa species)

unripe bunch ripening bunch Ripe

Plantain (Plantago major Linn.))

Plate 29 Musa species

Plate 30 a Cowpea (Vigna unguiculata)

Plantain (Plantago major Linn.)
140
 Plate 30 b Cray fish Millet

Groundnut seeds Dikanut seeds Melon seeds

Castor seeds Coconut Palm kernel

Plate 31 a

Oil bean seeds

Plate 31b

141
 Pod Seeds

Plate 32 Tetrapleura tetraptera (Uhiorkirihio) Plate 32b Monodora

myristica (Ehuru)

Bitter leaf Water leaf

(Vernonia amygdalina) (Talinum triangulare)

Green vegetable (Amaranthus spp)

Plate 33 142
 Yam tubers Rice grains

Cassava tubers Maize cobs

Plate 34 Staple Foods

Plate 35 Saw dust and poultry manure

143
 Aerial parts

Seeds

Plate 36. Centrocema pubescen Benth

144