A major limitation in nutritional science is the lack of understanding of the nutritional intake ... more A major limitation in nutritional science is the lack of understanding of the nutritional intake of free-living people. There is an inverse relationship between accuracy of reporting of energy intake by all current nutritional methodologies and body weight. In this pilot study we aim to explore whether using a novel lightweight, wearable micro-camera improves the accuracy of dietary intake assessment. Doubly labelled water (DLW) was used to estimate energy expenditure and intake over a 14-d period, over which time participants (n 6) completed a food diary and wore a micro-camera on 2 of the days. Comparisons were made between the estimated energy intake from the reported food diary alone and together with the images from the micro-camera recordings. There was an average daily deficit of 3912 kJ using food diaries to estimate energy intake compared with estimated energy expenditure from DLW (P = 0·0118), representing an under-reporting rate of 34 %. Analysis of food diaries alone showed a significant deficit in estimated daily energy intake compared with estimated intake from food diary analysis with images from the micro-camera recordings (405 kJ). Use of the micro-camera images in conjunction with food diaries improves the accuracy of dietary assessment and provides valuable information on macronutrient intake and eating rate. There is a need to develop this recording technique to remove user and assessor bias.
Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to impr... more Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to improve control through the avoidance of vitamin K-rich foods (mainly green vegetables) may inadvertently compromise folate status, itself a risk factor for thromboembolism. We evaluated the effect of a 6-month period of warfarin therapy on folate status in 114 patients using measurements of red-cell folate and 5-methyltetrahydrofolate and plasma folate and total homocysteine. Circulatory levels of phylloquinone, vitamin B12 and methylmalonic acid were also determined. A subset of 45 patients completed 7-day food diaries at the beginning and end of their treatment. There was a significant decrease in total erythrocyte folate (P = 0.005) and 5-methyltetrahydrofolate (P = 0.002) during the study. A concurrent increase in plasma phylloquinone (P = 0.003) was attributed to warfarin-induced perturbation of vitamin K metabolism. No other longitudinal changes were observed. Folate and phylloquinone intakes correlated with each other at baseline (P = 0.024) and after treatment (P = 0.011). Based on robust measurements of erythrocyte folates, patients showed a significant impairment in folate status after 6-month therapy with warfarin. The majority of patients had intakes of folate and phylloquinone below the national average or UK guidelines. The study highlights the need for improved dietary management of patients taking oral anticoagulants.
Abstract The prevalence of obesity worldwide presents a great challenge to existing healthcare sy... more Abstract The prevalence of obesity worldwide presents a great challenge to existing healthcare systems. There is a general need for pervasive monitoring of the dietary behaviour of those who are at risk of co-morbidities. Currently, however, there is no accurate method of assessing the nutritional intake of people in their home environment. Traditional methods require subjects to manually respond to questionnaires for analysis, which is subjective, prone to errors, and difficult to ensure consistency and compliance. In this ...
Accurate estimation of daily total energy expenditure
(EE) is a prerequisite for assisted weight ... more Accurate estimation of daily total energy expenditure (EE) is a prerequisite for assisted weight management and assessing certain health conditions. The use of wearable sensors for predicting free-living EE is challenged by consistent sensor placement, user compliance, and estimation methods used. This paper examines whether a single ear-worn accelerometer can be used for EE estimation under free-living conditions. An EE prediction model was first derived and validated in a controlled setting using healthy subjects involving different physical activities. Ten different activities were assessed showing a tenfold cross validation error of 0.24. Furthermore, the EE prediction model shows a mean absolute deviation below 1.2 metabolic equivalent of tasks. The same model was applied to a free-living setting with a different population for further validation. The results were compared against those derived from doubly labeled water. In free-living settings, the predicted daily EE has a correlation of 0.74, p = 0.008, and a MAD of 27 kcal/day. These results demonstrate that laboratory-derived prediction models can be used to predict EE under free-living conditions.
The prevalence of obesity worldwide presents a great challenge to existing healthcare systems. Th... more The prevalence of obesity worldwide presents a great challenge to existing healthcare systems. There is a general need for pervasive monitoring of the dietary behaviour of those who are at risk of co-morbidities. Currently, however, there is no accurate method of assessing the nutritional intake of people in their home environment. Traditional methods require subjects to manually respond to questionnaires for analysis, which is subjective, prone to errors, and difficult to ensure consistency and compliance. In this paper, we present a wearable sensor platform that autonomously provides detailed information regarding a subject's dietary habits. The sensor consists of a microphone and a camera and is worn discretely on the ear. Sound features are extracted in real-time and if a chewing activity is classified, the camera captures a video sequence for further analysis. From this sequence, a number of key frames are extracted to represent important episodes during the course of a meal. Results show a high classification rate of chewing activities, and the visual log demonstrates a detailed overview of the subject's food intake that is difficult to quantify from manually-acquired food records.
Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to impr... more Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to improve control through the avoidance of vitamin K-rich foods (mainly green vegetables) may inadvertently compromise folate status, itself a risk factor for thromboembolism. We evaluated the effect of a 6-month period of warfarin therapy on folate status in 114 patients using measurements of red-cell folate and 5-methyltetrahydrofolate and plasma folate and total homocysteine. Circulatory levels of phylloquinone, vitamin B12 and methylmalonic acid were also determined. A subset of 45 patients completed 7-day food diaries at the beginning and end of their treatment. There was a significant decrease in total erythrocyte folate (P = 0.005) and 5-methyltetrahydrofolate (P = 0.002) during the study. A concurrent increase in plasma phylloquinone (P = 0.003) was attributed to warfarin-induced perturbation of vitamin K metabolism. No other longitudinal changes were observed. Folate and phylloquinone intakes correlated with each other at baseline (P = 0.024) and after treatment (P = 0.011). Based on robust measurements of erythrocyte folates, patients showed a significant impairment in folate status after 6-month therapy with warfarin. The majority of patients had intakes of folate and phylloquinone below the national average or UK guidelines. The study highlights the need for improved dietary management of patients taking oral anticoagulants.
A major limitation in nutritional science is the lack of understanding of the nutritional intake ... more A major limitation in nutritional science is the lack of understanding of the nutritional intake of free-living people. There is an inverse relationship between accuracy of reporting of energy intake by all current nutritional methodologies and body weight. In this pilot study we aim to explore whether using a novel lightweight, wearable micro-camera improves the accuracy of dietary intake assessment. Doubly labelled water (DLW) was used to estimate energy expenditure and intake over a 14-d period, over which time participants (n 6) completed a food diary and wore a micro-camera on 2 of the days. Comparisons were made between the estimated energy intake from the reported food diary alone and together with the images from the micro-camera recordings. There was an average daily deficit of 3912 kJ using food diaries to estimate energy intake compared with estimated energy expenditure from DLW (P = 0·0118), representing an under-reporting rate of 34 %. Analysis of food diaries alone showed a significant deficit in estimated daily energy intake compared with estimated intake from food diary analysis with images from the micro-camera recordings (405 kJ). Use of the micro-camera images in conjunction with food diaries improves the accuracy of dietary assessment and provides valuable information on macronutrient intake and eating rate. There is a need to develop this recording technique to remove user and assessor bias.
Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to impr... more Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to improve control through the avoidance of vitamin K-rich foods (mainly green vegetables) may inadvertently compromise folate status, itself a risk factor for thromboembolism. We evaluated the effect of a 6-month period of warfarin therapy on folate status in 114 patients using measurements of red-cell folate and 5-methyltetrahydrofolate and plasma folate and total homocysteine. Circulatory levels of phylloquinone, vitamin B12 and methylmalonic acid were also determined. A subset of 45 patients completed 7-day food diaries at the beginning and end of their treatment. There was a significant decrease in total erythrocyte folate (P = 0.005) and 5-methyltetrahydrofolate (P = 0.002) during the study. A concurrent increase in plasma phylloquinone (P = 0.003) was attributed to warfarin-induced perturbation of vitamin K metabolism. No other longitudinal changes were observed. Folate and phylloquinone intakes correlated with each other at baseline (P = 0.024) and after treatment (P = 0.011). Based on robust measurements of erythrocyte folates, patients showed a significant impairment in folate status after 6-month therapy with warfarin. The majority of patients had intakes of folate and phylloquinone below the national average or UK guidelines. The study highlights the need for improved dietary management of patients taking oral anticoagulants.
Abstract The prevalence of obesity worldwide presents a great challenge to existing healthcare sy... more Abstract The prevalence of obesity worldwide presents a great challenge to existing healthcare systems. There is a general need for pervasive monitoring of the dietary behaviour of those who are at risk of co-morbidities. Currently, however, there is no accurate method of assessing the nutritional intake of people in their home environment. Traditional methods require subjects to manually respond to questionnaires for analysis, which is subjective, prone to errors, and difficult to ensure consistency and compliance. In this ...
Accurate estimation of daily total energy expenditure
(EE) is a prerequisite for assisted weight ... more Accurate estimation of daily total energy expenditure (EE) is a prerequisite for assisted weight management and assessing certain health conditions. The use of wearable sensors for predicting free-living EE is challenged by consistent sensor placement, user compliance, and estimation methods used. This paper examines whether a single ear-worn accelerometer can be used for EE estimation under free-living conditions. An EE prediction model was first derived and validated in a controlled setting using healthy subjects involving different physical activities. Ten different activities were assessed showing a tenfold cross validation error of 0.24. Furthermore, the EE prediction model shows a mean absolute deviation below 1.2 metabolic equivalent of tasks. The same model was applied to a free-living setting with a different population for further validation. The results were compared against those derived from doubly labeled water. In free-living settings, the predicted daily EE has a correlation of 0.74, p = 0.008, and a MAD of 27 kcal/day. These results demonstrate that laboratory-derived prediction models can be used to predict EE under free-living conditions.
The prevalence of obesity worldwide presents a great challenge to existing healthcare systems. Th... more The prevalence of obesity worldwide presents a great challenge to existing healthcare systems. There is a general need for pervasive monitoring of the dietary behaviour of those who are at risk of co-morbidities. Currently, however, there is no accurate method of assessing the nutritional intake of people in their home environment. Traditional methods require subjects to manually respond to questionnaires for analysis, which is subjective, prone to errors, and difficult to ensure consistency and compliance. In this paper, we present a wearable sensor platform that autonomously provides detailed information regarding a subject's dietary habits. The sensor consists of a microphone and a camera and is worn discretely on the ear. Sound features are extracted in real-time and if a chewing activity is classified, the camera captures a video sequence for further analysis. From this sequence, a number of key frames are extracted to represent important episodes during the course of a meal. Results show a high classification rate of chewing activities, and the visual log demonstrates a detailed overview of the subject's food intake that is difficult to quantify from manually-acquired food records.
Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to impr... more Dietary fluctuations of vitamin K are detrimental to oral anticoagulant control. Attempts to improve control through the avoidance of vitamin K-rich foods (mainly green vegetables) may inadvertently compromise folate status, itself a risk factor for thromboembolism. We evaluated the effect of a 6-month period of warfarin therapy on folate status in 114 patients using measurements of red-cell folate and 5-methyltetrahydrofolate and plasma folate and total homocysteine. Circulatory levels of phylloquinone, vitamin B12 and methylmalonic acid were also determined. A subset of 45 patients completed 7-day food diaries at the beginning and end of their treatment. There was a significant decrease in total erythrocyte folate (P = 0.005) and 5-methyltetrahydrofolate (P = 0.002) during the study. A concurrent increase in plasma phylloquinone (P = 0.003) was attributed to warfarin-induced perturbation of vitamin K metabolism. No other longitudinal changes were observed. Folate and phylloquinone intakes correlated with each other at baseline (P = 0.024) and after treatment (P = 0.011). Based on robust measurements of erythrocyte folates, patients showed a significant impairment in folate status after 6-month therapy with warfarin. The majority of patients had intakes of folate and phylloquinone below the national average or UK guidelines. The study highlights the need for improved dietary management of patients taking oral anticoagulants.
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Papers by Claire Pettitt
(EE) is a prerequisite for assisted weight management and assessing certain health conditions. The use of wearable sensors for predicting free-living EE is challenged by consistent sensor placement, user compliance, and estimation methods used. This paper examines whether a single ear-worn accelerometer can be used for EE estimation under free-living conditions. An EE prediction model was first derived and validated in a controlled setting using healthy subjects involving different physical activities. Ten different activities
were assessed showing a tenfold cross validation error of 0.24.
Furthermore, the EE prediction model shows a mean absolute deviation below 1.2 metabolic equivalent of tasks. The same model was applied to a free-living setting with a different population for further validation. The results were compared against those derived from doubly labeled water. In free-living settings, the predicted daily EE has a correlation of 0.74, p = 0.008, and a MAD of 27 kcal/day. These results demonstrate that laboratory-derived prediction models can be used to predict EE under free-living conditions.
(EE) is a prerequisite for assisted weight management and assessing certain health conditions. The use of wearable sensors for predicting free-living EE is challenged by consistent sensor placement, user compliance, and estimation methods used. This paper examines whether a single ear-worn accelerometer can be used for EE estimation under free-living conditions. An EE prediction model was first derived and validated in a controlled setting using healthy subjects involving different physical activities. Ten different activities
were assessed showing a tenfold cross validation error of 0.24.
Furthermore, the EE prediction model shows a mean absolute deviation below 1.2 metabolic equivalent of tasks. The same model was applied to a free-living setting with a different population for further validation. The results were compared against those derived from doubly labeled water. In free-living settings, the predicted daily EE has a correlation of 0.74, p = 0.008, and a MAD of 27 kcal/day. These results demonstrate that laboratory-derived prediction models can be used to predict EE under free-living conditions.