The validity of self-reported energy intake as determined using the doubly labelled water technique

A new statistical method for estimating the usual intake of episodically consumed foods with application to their distribution

OBJECTIVE

We propose a new statistical method that uses information from two 24-hour recalls to estimate usual intake of episodically consumed foods.

STATISTICAL ANALYSES PERFORMED

The method developed at the National Cancer Institute (NCI) accommodates the large number of nonconsumption days that occur with foods by separating the probability of consumption from the consumption-day amount, using a two-part model. Covariates, such as sex, age, race, or information from a food frequency questionnaire, may supplement the information from two or more 24-hour recalls using correlated mixed model regression. The model allows for correlation between the probability of consuming a food on a single day and the consumption-day amount. Percentiles of the distribution of usual intake are computed from the estimated model parameters.

RESULTS

The Eating at America's Table Study data are used to illustrate the method to estimate the distribution of usual intake for whole grains and dark-green vegetables for men and women and the distribution of usual intakes of whole grains by educational level among men. A simulation study indicates that the NCI method leads to substantial improvement over existing methods for estimating the distribution of usual intake of foods.

CONCLUSIONS

The NCI method provides distinct advantages over previously proposed methods by accounting for the correlation between probability of consumption and amount consumed and by incorporating covariate information. Researchers interested in estimating the distribution of usual intakes of foods for a population or subpopulation are advised to work with a statistician and incorporate the NCI method in analyses.

Can Self-Reported Dieting and Dietary Restraint Identify Underreporters of Energy Intake in Dietary Surveys?

Underreporting is endemic in most dietary studies and ways to reliably identify individuals who may underreport energy intake are needed. Whether questions on self-reported dieting and dietary restraint, in addition to weight status, would identify individuals who may underreport energy intakes was examined in a United Kingdom representative survey. Mean daily energy intake was calculated from the 7-day dietary record of 668 men and 826 women. Reported physical activity was used to assign each subject's activity level and to calculate estimated energy requirements from published equations. Underreporting was calculated as estimated energy requirements minus energy intake with adjustment for daily variation. The Dutch Eating Behavior Questionnaire assessed dietary restraint. Underreporting was higher in men and women reporting current dieting than nondieters (P<0.001) and higher in high-restrained (P<0.001) than low-restrained. When stratified by body mass index category, in men these associations were only significant in the overweight (P<0.001). Dieting was associated with greater underreporting in both lean (P<0.01) and overweight women (P<0.001). Underreporting was higher in lean high-restrained women than low-restrained (P=0.02), but similar in overweight women regardless of restraint score. Questions to assess dietary restraint and current dieting may be useful tools to identify and evaluate underreporting at an individual level in dietary surveys.

Validation of a self-completion measure of breakfast foods, snacks and fruits and vegetables consumed by 9- to 11-year-old schoolchildren

OBJECTIVE

To evaluate the validity and reliability of a dietary recall questionnaire, designed for group-level comparisons of foods eaten at breakfast and intake of fruits, vegetables, sweet items and crisps.

DESIGN

Validity was assessed relative to 24-h dietary recall interviews, and reliability by comparing the baseline data with 4-month follow-up data.

SUBJECTS AND SETTING

Fifty-eight schools took part in the validity assessments, with 374 children completing both measures. Reliability was assessed using 29 schools, with 1233 children at baseline and 1033 at follow-up. Children were aged 9-11 years and schools were located in socio-economically deprived areas of Wales.

RESULTS

Results indicated moderate to substantial agreements for most foods eaten at breakfast on the day of reporting and fair to moderate agreements for breakfast foods the previous day. For items throughout the rest of the previous day, agreement was fair to substantial during school hours, but slight after school. Correlations were moderate in terms of 'healthy' items and 'unhealthy' items consumed at breakfast on the day of reporting, but weaker for the previous breakfast. Correlations between measures in terms of fruits, vegetables, sweet items and crisps throughout the rest of the previous day were fair to moderate. The measure demonstrated fair to substantial group-level reliability.

CONCLUSIONS

The questionnaire, while subject to a number of limitations, gives an adequately valid and reliable overview of selected aspects of children's diet. It is likely to be of value at group-level in randomized controlled trials of school-based interventions.

Energy balance in weight stable athletes with and without menstrual disorders

The energy balance and nutritional adequacy was assessed in a group of runners with irregular menstrual function (IR, n = 10) and in a comparable group of runners with normal menstrual function (R, n = 10). Based on computerized records of 3 days food intake, the mean content of energy and macronutrients were estimated. Excess energy expenditure (EEE) during training hours was estimated using HF monitoring and individual HF/VO2 nomograms. For the rest of a daily 24 h cycle, estimated values for basal metabolic rate (BMR) and sedentary metabolic rate were applied. Daily training-related excess energy expenditure (2.1 +/- 0.3 vs 2.2 +/- 0.4) MJ (Mean +/- SEM) and total energy expenditure (TEE) (11.0 +/- 0.3 vs 11.2 +/- 0.4) MJ in R vs IR were not different in the two groups. Calculated daily energy intake (EI) was, however, significantly lower in IR (9.7 +/- 0.5 MJ) than in R (12.3 +/- 0.7 MJ), (P = 0.007). Calculated EI and TEE were in balance in R athletes. When the same calculations were applied on IR athletes, a moderate but statistically significant negative energy balance was found (-1.5 +/- 0.6 MJ, P = 0.03). The calculated energy deficit was supported by significantly lower levels of free thyroxine in IR athletes, and may indicate an adaptive lower BMR in IR athletes. Mean intakes of carbohydrates (7.0 g/kg in R and 5.7 g/kg in IR) and protein (1.71 g/kg in R and 1.49 g/kg in IR) were close to guidelines. Intakes were not significantly different in the two groups. The most important difference in macronutrient intake was found in dietary fat (1.70 g/kg in R and 1.04 g/kg in IR) that was significantly lower in the IR group than in the R group (P = 0.007). The weight stable IR and R athletes seemed to meet the recommended intake of carbohydrates, protein and fat in their diet fairly well. However, according to the present calculations, a small energy deficit was observed in IR athletes but not in R athletes. Compared with the intake of the R athletes, this energy deficit seems primarily to be related to a lower intake of dietary fat in IR athletes.

Perception, passive overfeeding and energy metabolism

The palatability of a diet is an important determinant of energy intake. Due to a high palatability, a relatively high energy density, and a weak effect on satiation, the consumption of high-fat foods induces passive overfeeding. It is well known that a high-fat diet often leads to a loss of portion control of tasty foods. Here, studies are reviewed on the effect of overfeeding on substrate utilization and energy expenditure. It is often suggested that humans differ in the susceptibility to weight gain in response to overfeeding. Six years ago, non-exercise activity thermogenesis was presented as a new mechanism to explain differences in weight gain between subjects. Activation of non-exercise activity thermogenesis could dissipate excess energy to preserve leanness and only failure to activate non-exercise activity thermogenesis resulted in ready fat gain. However, there is still little evidence for this form of adaptive thermogenesis from additional studies. The conclusion is that the fat content has an effect on body fat as a function of the effect of dietary fat on energy intake.

Diet, blood lipid profile and physical activity patterns in primary school children from a semi-rural area of Greece

BACKGROUND

Risk factors for heart disease are becoming increasingly prevalent among young populations. The aim of this study was to assess the cardiovascular risk profile of young adolescents living in a semi-rural area of mainland Greece, Volos.

MATERIALS AND METHODS

A total of 198 children (106 females and 92 males) aged 11.6 +/- 0.4 years were randomly recruited.

RESULTS

Mean body mass index was 20.4 +/- 3.5 kg m(-2), while 30.3% of children were overweight and 6.7% were obese; no differences were observed between boys and girls. Mean plasma cholesterol (4.93 +/- 0.75 mmol L(-1)), low-density lipoprotein-cholesterol (3.29 +/- 0.64 mmol L(-1)) and triglyceride (0.97 +/- 0.31 mmol L(-1)) concentrations were above age-specific recommended values. On the other hand, mean high-density lipoprotein-cholesterol was acceptable for 92.3% of the children. Self-reported daily energy intake (8.37 +/- 3.06 MJ) was adequate for age, but intake of fat was high (42.0 +/- 9.2% of energy) and that of carbohydrate was relatively low (44.5 +/- 10.0% of energy). Saturated fat consumption was elevated (15.6 +/- 4.3% of energy), while polyunsaturated fat intake fell short (4.8 +/- 1.6% of energy). The study participants spent 9.60 +/- 6.44 h week(-1) on moderate to vigorous physical activities, while they devoted 16.60 +/- 8.81 h week(-1) to sedentary activities. Boys spent significantly more time than girls on both physical (P < 0.001) and sedentary (P = 0.001) activities. No major gender differences were observed in anthropometric, dietary and plasma lipid parameters.

CONCLUSION

The findings from the present study support the worrisome trends that have been documented in Greek youngsters elsewhere, and predict an unfavourable cardiovascular risk profile for the Greek population in the foreseeable future.

Normal-weight adults consume more fiber and fruit than their age- and height-matched overweight/obese counterparts

OBJECTIVES

To assess differences in dietary intake of overweight/obese subjects and sex-, age-, and height-matched controls and to identify dietary components associated with increased deposition of body fat.

DESIGN/SUBJECTS

A convenience sample of 52 overweight/obese and 52 normal-weight adults matched for sex, age (+/-1 year), and height (+/-1 inch) were recruited from the local area. Dietary intake was assessed with the Block 60-item food frequency questionnaire, physical activity was measured by the Yale Physical Activity Survey, and percent body fat was measured via dual-energy x-ray absorptiometry.

STATISTICAL ANALYSES PERFORMED

Independent t tests compared between-group consumption of dietary components. The ability of dietary components to predict percent body fat before and after controlling for age-, sex-, and physical activity-related energy expenditure and other macronutrients was assessed with multiple regression analyses. Spearman correlation coefficients examined relationships among nutrients, Food Guide Pyramid servings, and percent body fat.

RESULTS

Overweight/obese subjects consumed more total fat, saturated fat, and cholesterol and less carbohydrate, complex carbohydrate, and dietary fiber than control subjects. Reported intake of dietary fiber was inversely related to percent body fat without (R(2)=0.052, P=0.02) and with (R(2)=0.045, P=0.013) control for potential confounding factors. Servings of fruit per day were negatively related to percent body fat (r=-0.40, P<0.01).

CONCLUSIONS

These findings suggest that the composition of a diet, especially low dietary fiber and fruit intake, plays a role in the etiology of obesity.

Energy balance and physical activity in obese children attending day-care centres

OBJECTIVE

To evaluate energy balance and physical activity in obese preschool children attending day-care centres.

DESIGN

Cross-sectional study.

SUBJECTS

Twenty-four 3-5 years old obese children selected at random from four different day-care centres in Santiago City, Chile. Total energy expenditure (TEE) was measured by doubly labelled water and physical activity as recorded by TRITRAC R3D motion sensor. Energy intake was assessed by measuring food intake while at the centre, along with the recording of additional food intake in the home.

RESULTS

Obese children had a 5.4% higher weighed energy intake than their energy requirements 2001. Energy intake during the week was 7716+/-1092 kJ/day and 7401+/-1023 kJ/day in boys and girls, respectively. Minimal activity was higher in the day-care centres (62%) compared to 52% during the weekend at home. Light activity was higher during the weekend at home than during the week (25 versus 20%), but moderate-intense activity was similar (3-5%).

CONCLUSIONS

Reduction in dietary energy provided at the day-care centres helps to balance energy requirements during the week. Obese children had marked sedentary characteristics with regards to physical activity, although children are more active at home in weekends. This situation suggests that educators and parents need to improve children's physical activity levels and nutrition habits.

Calorie intake misreporting by diet record and food frequency questionnaire compared to doubly labeled water among postmenopausal women

OBJECTIVE

We assessed the extent of energy misreporting from the use of a self-administered 7-day diet record (7-DDR) and a widely used food frequency questionnaire (FFQ) compared to total energy expenditure from doubly labeled water (DLW) in a group of postmenopausal women.

DESIGN

At baseline, 65 healthy postmenopausal women were instructed to fill out the National Cancer Institute's (NCI) FFQ and a 7-DDR. Average total energy expenditure using the DLW method was also performed at baseline.

RESULTS

On average, the women underestimated total energy intake compared to total energy expenditure assessed from DLW by 37% on the 7-DDR and 42% on the FFQ.

CONCLUSIONS

These findings suggest that the interpretation of findings from the 7-DDR- and FFQ-based energy-disease association studies in postmenopausal women needs further evaluation.

SPONSORSHIP

This research was supported (in part) by the Intramural Program of the NIH (National Cancer Institute).

Trends in energy and macronutrient intakes in non-under-reporters vary with the method used to identify under-reporters

OBJECTIVE

To investigate effects of using different methods to identify under-reporters on trends in dietary intake and physical activity level (PAL) in non-under-reporters.

DESIGN

Dietary intake and activity pattern were recorded by 887 female university students from 1988 to 2003. Energy expenditure (EE) and PAL were measured using a factorial method. Nine methods were used to identify under-reporters. Trends between 1988 and 2003 were determined from linear regression of median data for each year.

RESULTS

Prevalence of under-reporting varied with the method used, ranging from 22.2% to 66.7%. Trends that were consistent using all methods were a decrease in per cent of energy from fat and no change in alcohol intake or PAL (P<0.05). Trends in energy and macronutrient intakes varied with the method used. Using the four methods that excluded the most under-reporters there were increases in energy and gram carbohydrate (CHO) intakes (P<0.05), but no change in gram fat intake. Using the four methods that excluded the fewest under-reporters there was no change in energy or gram CHO intake, but a decrease in gram fat intake (P<0.05).

CONCLUSION

Trends in energy, fat and CHO intakes in non-under-reporters varied with the method used to identify under-reporters.

The Psychosocial and Behavioral Characteristics Related to Energy Misreporting

Energy underreporting occurs in 2% to 85% and overreporting in 1% to 39% of various populations. Efforts are needed to understand the psychosocial and behavioral characteristics associated with misreporting to help improve the accuracy of dietary self-reporting. Past research suggests that higher social desirability and greater eating restraint are key factors influencing misreporting, while a history of dieting and being overweight are more moderately associated. Eating disinhibition, body image, depression, anxiety, and fear of negative evaluation may be related to energy misreporting, but evidence is insufficient. This review will provide a detailed discussion of the published associations among psychosocial and behavioral characteristics and energy misreporting.

Nutrition problems in an obesogenic environment

Many claims about nutrition and weight loss stem from small, short-term studies, incorrect interpretations or distortions of evidence. Our knowledge of what people eat is poor; difficulties include accurate assessment of consumption, the complex composition of foods and individual variations in nutrient bioavailability. When advice appears to be ineffective, poor compliance is a likely explanation. There is no simple solution to obesity, and no fast way to create the energy deficit required for sustainable loss of fat - weight loss requires long-term commitment to permanently change eating and exercise habits. Valid advice is to reduce overall energy intake, include more vegetables, fruits and whole grain products and fewer foods high in saturated fat, sugar and salt. While mindful of the need to encourage individuals to make changes, the medical profession needs to lead the charge to advocate for changes to our obesogenic environment.

Sarcopenia in premenopausal and postmenopausal women with osteopenia, osteoporosis and normal bone mineral density

Sarcopenia, the decline of muscle mass with age, causes impaired gait, disability and falls. It may therefore increase the risk of fracture for osteoporotic women. The aims of this study were to determine the prevalence of sarcopenia in osteopenic and osteoporotic women, and to determine if hormone replacement therapy (HRT), diet, or physical activity (PA) has a role in the prevention of sarcopenia. One hundred and thirty-one premenopausal and 82 postmenopausal (54 taking HRT) healthy women (17-77 years) volunteered for the study. Body composition was measured by dual X-ray absorptiometry (DXA). Sarcopenia was defined as a relative skeletal muscle index (RSMI) (appendicular skeletal muscle mass divided by height) below 5.45 kg/m2. Osteopenia was defined by a densitometric t-score for bone mineral density (BMD) (g/cm2) below -1.0 and osteoporosis by a t-score below -2.5. Nutrient intake was assessed using 3-day food records and physical activity (PA) was measured using the Baecke Physical Activity Questionnaire. Pearson chi-squared, independent t-tests, simple correlation and multiple regression were used to analyze the data. In premenopausal osteopenic women the prevalence of sarcopenia was 12.5%. In postmenopausal women it was 25% for those with osteopenia, and 50% for those with osteoporosis. PA was independently related to RSMI (beta=0.222, p=0.0001), but diet and HRT were not. After adjusting for PA, RSMI was not significantly related to BMD. These data suggest that the relationship between RSMI, BMD and risk of osteoporosis may largely be mediated through participation in PA. Sarcopenia screening simultaneous to BMD examinations by DXA, may be of value in identifying osteoporotic women with sarcopenia, a group that may be most in need of exercise interventions to increase muscle and BMD.

Fitness-for-purpose of dietary survey duration: a case-study with the assessment of exposure to ochratoxin A

The duration of food consumption survey may have a marked effect on estimates of usual nutrient intakes in individuals and groups. This arises from a high degree of within-person variability in food intakes, primarily on a day-to-day basis. Both the level of observation-populations versus individuals-and the desirable level of precision decide upon the 'fitness-for-purpose' of dietary survey duration. Though similar from a methodological standpoint, the question was rarely addressed in the case of non-nutrients. Our work aims at estimating the number of days of food records needed for the assessment of usual intakes of food chemicals as a function of research purpose. Focusing on the French population exposure to food mycotoxin ochratoxin A, we implement a range of well-established methods borrowed from the field of nutrient intakes assessment. Our results on OTA show that: (a) at the population level, as low as three days give satisfactory distributional estimates; yet, the implementation of variance reduction methods is of particular relevance when higher percentiles of exposure are at stake; (b) the estimation of individual usual intakes based on food records is behind practical possibilities, which calls for alternative options such as biomarkers of exposure.

Handling of contamination variability in exposure assessment: A case study with ochratoxin A

The contamination of foods dedicated to human consumption varies over space and time. In exposure assessment, this is usually addressed through probabilistic modelling. The present work explores how the variability and uncertainty of exposures estimated at the population level are affected by: (a) the (non-)parametric nature of input contamination distributions; (b) the time-window used to sample contamination values within those distributions. Focusing on exposure of the French population to food mycotoxin ochratoxin A, we implement a range of second-order Monte-Carlo simulations that allow distinguishing variability of exposures from uncertainty of distributional parameters estimates. A simulation runs 10,000 iterations. Overall estimates of parameters are given by the median across iterations and 95%CI by 2.5th and 97.5th percentiles. Our results show that: (a) parametric (log-normal) input distributions may lead to over-estimation of variability and greater uncertainty as compared to non-parametric ones (P97.5 [95%CI] of 7.1 [6.6;7.7] for Parametric-Occasion, 4.6 [4.3;5.0] for Non-Parametric-Occasion), and that (b) the 'Occasion' time-window combines better estimate of variability and lower uncertainty when exposure modelling is applied to populations living in developed countries with complex agri-food systems (P97.5 [95%CI]: 7.3 [6.2;8.9] for Non-Parametric-Week, 4.6 [4.3;5.0] for Non-Parametric-Occasion). A deterministic approach is nevertheless preferred to probabilistic modelling every time input data quality is questionable.

Validation of energy intake by 24-hour multiple pass recall: comparison with total energy expenditure in children aged 5-7 years

Accurate measurement of energy intake (EI) is essential in studies of energy balance in all age groups. Reported values for EI can be validated against total energy expenditure (TEE) measured using doubly labelled water (DLW). Our previous work has indicated that the use of the standardized 24 h multiple pass recall (24 h MPR) method produces slight overestimates of EI in pre-school children which are inaccurate at individual level but acceptable at group level. To extend this work, the current study validated EI by 24 h MPR against TEE by DLW in sixty-three (thirty-two boys) school-aged children (median age 6 years). In both boys and girls, reported EI was higher than TEE, although this difference was only significant in the girls (median difference 420 kJ/d, P=0.05). On analysis of agreement between TEE and EI, the group bias was an overestimation of EI by 250 kJ/d with wide limits of agreement (-2880, 2380 kJ/d). EI was over-reported relative to TEE by 7 % and 0.9 % in girls and boys, respectively. The bias in the current study was lower than in our previous study of pre-school children, suggesting that estimates of EI become less inaccurate as children age. However, the current study suggests that the 24 h MPR is inaccurate at the individual level.

Comparative Validation of a Bilingual Interactive Multimedia Dietary Assessment Tool

OBJECTIVE

To perform comparative validity testing for a bilingual interactive multimedia (IMM) dietary assessment tool that mimics a dietary recall against an interview-administered dietary recall.

DESIGN

This was a two-period crossover design study. First, participants were randomly assigned to complete an IMM recall or interview-administered 24-hour recall. The IMM recall generated a nutrient profile that included 20 dietary constituents. The interview-administered recall was analyzed using the Food Intake Analysis System (FIAS) and the Expanded Food and Nutrition Education Program (EFNEP) Evaluating/Reporting System. The effect of substituting standardized portion sizes for reported portion sizes was examined.

SUBJECTS/SETTING

Of 80 adult participants, 71 (91%) were female, 45 (56%) had 12th grade or less education, 65 (81%) had an annual income of dollar 15,000 or less, and 21 (26%) completed the IMM recall in Spanish.

STATISTICAL ANALYSES PERFORMED

Analysis of variance and unadjusted and energy-adjusted correlations were used.

RESULTS

No significant group differences were found for order of administration or demographic characteristics. There was only one significant (P=.025) method effect, whereby vitamin C intake was higher in the IMM recall than the FIAS. The unadjusted correlations between the IMM recalls and interview-administered recalls analyzed using both FIAS and EFNEP Evaluating/Reporting System were generally approximately 0.6. Energy-adjusted correlations were consistently lower. Substituting standardized portion sizes resulted in significant differences for six nutrients and caused all correlations to decrease.

CONCLUSIONS

The IMM dietary recall is a valid method for assessing dietary intake within the tested group. The results of comparative validity testing and positive reactions received from participants and nutrition educators indicate that diet assessment using IMM has tremendous potential.

An easy-to-use semiquantitative food record validated for energy intake by using doubly labelled water technique

BACKGROUND

Estimating dietary intake is important for both epidemiological and clinical studies, but often lacks accuracy.

OBJECTIVE

To investigate the accuracy and validity of energy intake estimated by an easy-to-use semiquantitative food record (EI(SQFR)) compared to total energy expenditure (TEE) estimated by doubly labelled water technique (EE(DLW)).

DESIGN

TEE was measured in 29 nonobese subjects using the doubly labelled water method over a period of 14 days. Within this period, subjects reported their food consumption by a newly developed semiquantitative food record for 4 consecutive days. Energy intake was calculated using the German Food Code and Nutrition Data Base BLS II.3.

RESULTS

A good correlation was observed between EI(SQFR) and EE(DLW) (r = 0.685, P < 0.001). The mean difference between EI(SQFR) and EE(DLW) was -1.7+/-2.6 MJ/day (-14+/-21%, P = 0.002). An underestimation of EI(SQFR) <10% was observed in nine subjects (31%), of 10-20% in six subjects (21%), and of >20% in nine subjects (31%). In five subjects (17%), an overestimation of EI(SQFR) was observed.

CONCLUSIONS

The easy-to-use semiquantitative food record provided good estimates of EI in free-living and nonobese adults without prior detailed verbal instructions. The presented food record has limitations regarding accuracy at the individual level.

Adolescent Girls in Maine Are at Risk for Vitamin D Insufficiency

The objective was to determine the seasonal fluctuations in serum 25-hydroxyvitamin D (25-OHD) in a group of healthy adolescents living in a northern climate. Twenty-three 9- to 11-year-old girls participated in the study from September 2000 to March 2003. Serum 25-OHD and parathyroid hormone levels were measured each September and March. Dietary intake of vitamin D was assessed each summer and winter. Summer-sun exposure was evaluated using reports of time spent outdoors. The mean decrease in serum 25-OHD from September to March was 28%. Vitamin D insufficiency (at least one serum 25-OHD level <50 nmol/L) was observed in 11 of 23 (48%) subjects. Four of 23 subjects (17%) exhibited vitamin D insufficiency in both September and March. Mean parathyroid hormone levels increased 4 pg/mL (15%) from September to March. Vitamin D intakes need to be increased in winter at northern latitudes.

Anorexia athletica

In many sports, athletes with low body weight have a distinct advantage over their opponents; however, this advantage can easily turn into a noticeable disadvantage because low body weight may also be associated with health problems. The present review focuses on the problem of anorexia athletica, with its emphasis on leanness and thinness in female and male sports athletes. Athletes often restrict calories and/or overexercise to achieve or maintain low body and fat masses. There is a growing body of evidence that several metabolic and endocrine disturbances are the result of prolonged energy restriction. However, the long-term outcome of such sport-related disordered eating has not been thoroughly studied. Effective methods of treatment are scarce and similar to treatment of eating disorders. Scientific studies are needed that help establish alternative regulations for sports in which a low body weight is a primary advantage for performance.

Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism

BACKGROUND

Prolonged dietary restriction increases the life span in rodents. Some evidence suggests that alternate-day fasting may also prolong the life span.

OBJECTIVE

Our goal was to determine whether alternate-day fasting is a feasible method of dietary restriction in nonobese humans and whether it improves known biomarkers of longevity.

DESIGN

Nonobese subjects (8 men and 8 women) fasted every other day for 22 d. Body weight, body composition, resting metabolic rate (RMR), respiratory quotient (RQ), temperature, fasting serum glucose, insulin, free fatty acids, and ghrelin were assessed at baseline and after 21 d (12-h fast) and 22 d (36-h fast) of alternate-day fasting. Visual analogue scales were used to assess hunger weekly.

RESULTS

Subjects lost 2.5 +/- 0.5% of their initial body weight (P < 0.001) and 4 +/- 1% of their initial fat mass (P < 0.001). Hunger increased on the first day of fasting and remained elevated (P < 0.001). RMR and RQ did not change significantly from baseline to day 21, but RQ decreased on day 22 (P < 0.001), which resulted in an average daily increase in fat oxidation of > or =15 g. Glucose and ghrelin did not change significantly from baseline with alternate-day fasting, whereas fasting insulin decreased 57 +/- 4% (P < 0.001).

CONCLUSIONS

Alternate-day fasting was feasible in nonobese subjects, and fat oxidation increased. However, hunger on fasting days did not decrease, perhaps indicating the unlikelihood of continuing this diet for extended periods of time. Adding one small meal on a fasting day may make this approach to dietary restriction more acceptable.

Validation of energy intake by dietary recall against different methods to assess energy expenditure

OBJECTIVES

To compare the validity of dietary recalls and physical activity recalls and investigate some factors influencing this validity. To provide an example showing how procedures based on recalls of physical activity can assess the validity of dietary recalls and identify subjects constantly underreporting their energy intake (EI).

DESIGN AND SUBJECTS

Thirty-seven women were studied using three 24-h dietary recalls, two kinds of physical activity recalls, indirect calorimetry and the doubly labelled water method.

RESULTS

The EI obtained using dietary recalls were biased with respect to body mass index (BMI) and attitudes towards body weight and dieting, whereas results obtained using a physical activity recall were not. Eighteen women produced underreports (UR), i.e. their average EI was below 76% of total energy expenditure (TEE), whereas 24 women reported an EI that was lower than TEE on all three recall days, i.e. constantly underreporting subjects. A physical activity recall identified 13 URs and 20 of the constantly underreporting subjects.

CONCLUSIONS

In contrast to estimates of EI, TEE assessed using physical activity recalls was not biased with respect to BMI or attitudes towards body weight and dieting. Recalls of physical activity represent potentially useful procedures for identifying URs and constantly underreporting subjects but are not accurate enough for individuals.

Comparison of dietary intakes associated with metabolic syndrome risk factors in young adults: the Bogalusa Heart Study

BACKGROUND

Previous studies suggested that dietary intakes affect individual risk factors associated with metabolic syndrome.

OBJECTIVE

The objective of this study was to examine dietary intakes in 1181 young adults aged 19-38 y (38.1% men; 25% African Americans and 75% whites) in relation to metabolic syndrome risk factors in the Bogalusa Heart Study.

DESIGN

Participants were stratified into 3 groups according to the number of risk factors (0, 1-2, >/=3) associated with the metabolic syndrome according to the diagnostic criteria of the National Cholesterol Education Program, and dietary intakes were compared between the groups with a cross-sectional analysis.

RESULTS

After adjustment for age, total energy intake, body mass index, and physical activity, mean (+/-SE) intakes of fruit, fruit juice, and vegetables were significantly higher in subjects who had no risk factors than in subjects who had 1-2 risk factors (3.30 +/- 0.09 compared with 2.99 +/- 0.07 servings/d; P < 0.05). The mean intake of sweetened beverages was lower in subjects who had no risk factors than in subjects who had 1-2 risk factors or >/=3 risk factors among whites (1.45 +/- 0.08 compared with 1.77 +/- 0.07 and 2.22 +/- 0.15 serving/d, respectively, in men; 1.26 +/- 0.06 compared with 1.62 +/- 0.05 and 1.78 +/- 0.13 servings/d, respectively, in women; P < 0.001) but not among African Americans.

CONCLUSION

Our results suggest that low fruit and vegetable consumption and high sweetened beverage consumption are independently associated with the prevalence of metabolic syndrome in specific sex-ethnicity populations.

Severity and pattern of injury in survivors of alpine fall accidents

Few data are available on the medical aspects of fall accidents in mountainous terrain. Therefore, we report the severity and pattern of injury in 97 survivors of a major fall in Alpine terrain. Twenty-eight of 97 victims (29%) had severe or critical multisystem trauma, with an injury severity score >/=14, the incidence increasing to 23 out of 28 (82%) in individuals with falls exceeding 50 m. Fractures of the extremities and the sacropelvic region (n = 55) were the most common injuries. Seventeen of 21 spine fractures (81%) occurred in the thoracolumbar region. Rib fractures were found in 17 victims, in eight of them (47%) with an accompanying pneumothorax. Critical head trauma with a Glasgow Come Scale below 9 was rather uncommon (n = 6); abdominal visceral injuries were rare (n = 2). The pattern of injury observed in our study suggests a feet- or side-first body position at impact in the majority of individuals surviving Alpine fall accidents. Furthermore, it indicates a direct impact, rather than deceleration type mechanism of injury. Because of the high incidence of severe multisystem trauma, major fall in Alpine terrain should be used as triage criterion for the dispatch of an advanced trauma life support unit and direct transfer of the victim to a trauma center. Considering the high incidence of fractures, measures for adequate immobilization and analgesia will generally be necessary before the difficult evacuation from the site of the accident can be started.

Bone Mineral Density of Olympic-Level Female Winter Sport Athletes

PURPOSE

To compare areal bone mineral density (aBMD) of female winter sport athletes to healthy controls of similar age and body mass index (BMI).

METHODS

Areal BMD (g x cm(-2)) of the whole body, lumbar spine (L2-L4), and right proximal femur were assessed by dual energy x-ray absorptiometry in athletes (N = 40; age: 26.1 +/- 5.7 yr; ht: 165.6 +/- 0.1 cm; wt: 63.0 +/- 6.5 kg; BMI: 23.0 +/- 1.9 kg x m(-2)) involved in speed skating (N = 9), snowboarding (N = 13), freestyle skiing (N = 3), biathlon (N = 8), bobsleigh, skeleton, luge (N = 7), and controls (N = 21; age: 26.0 +/- 5.1 yr; ht: 165.8 +/- 0.1 cm; wt: 62.8 +/- 5.9 kg; BMI: 22.9 +/- 1.3 kg x m(-2)).

RESULTS

Using independent t-tests, athletes had lower fat mass, percent body fat, and higher lean mass than controls (P < 0.001). Areal BMD was higher in athletes than controls for all skeletal sites (P </= 0.007). With lean tissue mass as a covariate (ANCOVA), differences in aBMD remained significant for most skeletal sites (P </= 0.016). Menstrual history, mean daily calcium intake, and oral contraceptive use were not associated with aBMD in the athletic group.

CONCLUSION

Results show that female winter sport athletes have greater aBMD compared with controls of similar age and BMI. Most aBMD differences remained significant after adjusting for lean tissue mass, and athletes with a history of oligo- and/or amenorrhea had similar aBMD than their eumenorrheic counterparts. This is the first study to examine aBMD in winter sport athletes. The results support the hypothesis that the loading characteristics of intense winter sport participation have osteogenic potential.

Accuracy of dietary recall using the USDA five-step multiple-pass method in men: an observational validation study

OBJECTIVE

This observational validation study was conducted under controlled conditions to test the accuracy of dietary recall in normal weight, overweight, and obese men using the USDA five-step multiple-pass method for dietary recall.

DESIGN

Cross-sectional analysis of actual and recalled intake of food during 1 day.

SUBJECTS/SETTING

Forty-two men ranging in age from 21 to 65 years and in body mass index from 21 to 39 kg/m(2) who lived in the metropolitan Washington DC area were studied.

INTERVENTION

The subjects selected and consumed all meals and snacks, for 1 day, from a wide variety of foods provided at a human study facility.

MAIN OUTCOME MEASURES

Actual and recalled energy, protein, carbohydrate, and fat intakes were determined by direct observation and by a 24-hour dietary recall, respectively. Dietary recall was determined via telephone administration of the USDA five-step multiple-pass method the following day.

STATISTICAL ANALYSES PERFORMED

Analysis of variance and covariance tested the overall accuracy of recall and the effect of body mass index on dietary recall. Bland-Altman plots were used to assess bias in recall of food intake.

RESULTS

In this population of men, there were no significant differences between actual and recalled intakes of energy (3,294+/-111 and 3,541+/-124 kcal/day), protein (117+/-5 and 126+/-5 g/day), carbohydrate (414+/-16 and 449+/-16 g/day), or fat (136+/-7 and 146+/-8 g/day), respectively. Accuracy of recall was not related to body mass index in that the obese men recalled food intake as accurately as the nonobese men. The energy intake of these men was significantly correlated (r=0.57, P<.05) with their estimated energy requirements. Significant interindividual variation in accuracy of recall was found.

CONCLUSIONS

Under controlled conditions, the USDA five-step multiple-pass method can accurately assess intakes of energy, protein, carbohydrate, and fat in a population of men regardless of their body mass index. Researchers and clinical dietitians need to continue to examine factors that influence underreporting and overreporting of food intake by the multiple-pass 24-hour recall method.

A genome-wide linkage scan for dietary energy and nutrient intakes: the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study

BACKGROUND

A poor diet is a risk factor for chronic diseases such as obesity, cardiovascular disease, hypertension, and some cancers. Twin and family studies suggest that genetic factors potentially influence energy and nutrient intakes.

OBJECTIVE

We sought to identify genomic regions harboring genes affecting total energy, carbohydrate, protein, and fat intakes.

DESIGN

We performed a genomic scan in 347 white sibling pairs and 99 black sibling pairs. Dietary energy and nutrient intakes were assessed by using Willett's food-frequency questionnaire. Single-point and multipoint Haseman-Elston regression techniques were used to test for linkage. These subjects were part of the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study, a multicenter project undertaken by 5 laboratories.

RESULTS

In the whites, the strongest evidence of linkage appeared for dietary energy and nutrient intakes on chromosomes 1p21.2 (P = 0.0002) and 20q13.13 (P = 0.00007), and that for fat intake appeared on chromosome 12q14.1 (P = 0.0013). The linkage evidence on chromosomes 1 and 20 related to total energy intake rather than to the intake of specific macronutrients. In the blacks, promising linkages for macronutrient intakes occurred on chromosomes 12q23-q24.21, 1q32.1, and 7q11.1. Several potential candidate genes are encoded in and around the linkage regions on chromosomes 1p21.2, 12q14.1, and 20q13.13.

CONCLUSIONS

These are the first reported human quantitative trait loci for dietary energy and macronutrient intakes. Further study may refine these quantitative trait loci to identify potential candidate genes for energy and specific macronutrient intakes that would be amenable to more detailed molecular studies.

Psychosocial predictors of energy underreporting in a large doubly labeled water study

BACKGROUND

Underreporting of energy intake is associated with self-reported diet measures and appears to be selective according to personal characteristics. Doubly labeled water is an unbiased reference biomarker for energy intake that may be used to assess underreporting.

OBJECTIVE

Our objective was to determine which factors are associated with underreporting of energy intake on food-frequency questionnaires (FFQs) and 24-h dietary recalls (24HRs).

DESIGN

The study participants were 484 men and women aged 40-69 y who resided in Montgomery County, MD. Using the doubly labeled water method to measure total energy expenditure, we considered numerous psychosocial, lifestyle, and sociodemographic factors in multiple logistic regression models for prediction of the probability of underreporting on the FFQ and 24HR.

RESULTS

In the FFQ models, fear of negative evaluation, weight-loss history, and percentage of energy from fat were the best predictors of underreporting in women (R(2) = 0.09); body mass index, comparison of activity level with that of others of the same sex and age, and eating frequency were the best predictors in men (R(2) = 0.10). In the 24HR models, social desirability, fear of negative evaluation, body mass index, percentage of energy from fat, usual activity, and variability in number of meals per day were the best predictors of underreporting in women (R(2) = 0.22); social desirability, dietary restraint, body mass index, eating frequency, dieting history, and education were the best predictors in men (R(2) = 0.25).

CONCLUSION

Although the final models were significantly related to underreporting on both the FFQ and the 24HR, the amount of variation explained by these models was relatively low, especially for the FFQ.

Predictors of children's body mass index: a longitudinal study of diet and growth in children aged 2–8 y

OBJECTIVE

To identify longitudinal variables related to children's body mass index (BMI) (kg/m(2)) at age 8 y.

DESIGN

A longitudinal design, with nine interviews per child from ages 2 to 8 y.

SUBJECTS

In all, 70 white children (37 males, 33 females) who were continuous participants since infancy in the longitudinal study. Families were primarily middle and upper socioeconomic status.

MEASUREMENTS

At each interview, children's height and weight were measured, and mothers provided 3 days of the child's intake data (a 24-h recall and 2 days of food records).

ANALYSES

Analyses used were means+/-s.d., correlations, repeated measures analysis of variance, and forward stepwise regression. BMI at each interview was calculated and age of adiposity rebound was determined.

RESULTS

Children's BMI at 8 y was negatively predicted by age of adiposity rebound and positively predicted by their BMI at 2 y. Additionally, each model included one longitudinal dietary variable; mean protein and fat intakes recorded between 2 and 8 y were positive predictors of BMI at 8 y; mean carbohydrate intake over the same time period was negatively related to BMI at 8 y. R(2) values indicated that these three-variable models predicted 41-43% of the variability in BMI among children. BMI of 23% of the children exceeded the 85th CDC percentile.

CONCLUSIONS

The results of this study show that factors in early life are associated with children's BMI at age 8 y.

A comparison of self-reported energy intake with total energy expenditure estimated by accelerometer and basal metabolic rate in African-American women with type 2 diabetes

OBJECTIVE

This study assesses the validity of dietary data from African-American women with type 2 diabetes by comparing reported energy intake (EI) with total energy expenditure (TEE) estimated by an accelerometer and basal metabolic rate (BMR).

RESEARCH DESIGN AND METHODS

EI of 200 African-American women was assessed by three telephone-administered 24-h diet recalls using a multiple-pass approach. Physical activity was measured over a 7-day period by accelerometer, which also provided an estimate of TEE. Underreporting of EI was determined by using cutoffs for EI-to-TEE and EI-to-BMR ratios.

RESULTS

Participants, on average, were 59 years of age, with a BMI of 35.7, 10.5 years of diagnosed diabetes, and 10.7 years of education. Mean EI was 1,299 kcal/day; mean EI-to-TEE and EI-to-BMR ratios were 0.65 and 0.88, respectively. Among the 185 subjects with complete dietary data, 81% (n=150) were classified as energy underreporters using the EI-to-TEE ratio cutoff; 58% (n=107) were classified as energy underreporters using the EI-to-BMR ratio. Energy underreporters had significantly lower reported fat, higher protein, but similar carbohydrate intakes compared with non-underreporters. The EI-to-TEE ratio was not significantly associated with any demographic variables or following a diet for diabetes, but it was inversely associated with BMI (r=-0.37, P<0.0001). In a multivariate model, demographic variables, BMI, and following a diet for diabetes explained 16% of the variance in the EI-to-TEE ratio, with the latter two variables being the only significant predictors (inversely associated).

CONCLUSIONS

Widespread energy underreporting among this group of overweight African-American women with type 2 diabetes severely compromised the validity of self-reported dietary data.

Comparison of commonly used procedures, including the doubly-labelled water technique, in the estimation of total energy expenditure of women with special reference to the significance of body fatness

According to the report of the World Health Organization (1985), total energy expenditure (TEE) in human subjects can be calculated as BMR x physical activity level (PAL). However, other reports have pointed out limitations in the suggested procedure related to the % body fat of the subjects. The purpose of the present study was to evaluate the World Health Organization (1985) procedure in thirty-four healthy women with BMI 18-39 kg/m2. BMR and TEE were measured using indirect calorimetry (BMRmeas) and the doubly-labelled water method (TEEref) respectively. When assessed using the doubly-labelled water and skinfold-thickness methods, the women had 34 (SD 8) and 33 (SD 6) % body fat respectively. On the basis of guidelines provided by the World Health Organization (1985), 1.64 was selected to represent the average PAL of the women. Furthermore, PAL was also assessed by means of an accelerometer (PALacc), heart-rate recordings (PAL(HR)) and a questionnaire (PALq). These estimates were: PALacc 1.71 (SD 0.17), PAL(HR) 1.76 (SD 0.24), PALq 1.86 (SD 0.27). These values were lower than TEEref/BMRref, which was 1.98 (SD 0.21). BMR assessed using equations recommended by the World Health Organization (1985) (BMRpredicted) overestimated BMR by 594 (SD 431) kJ/24 h. However, when TEE was calculated as BMRpredicted x PALacc, BMRpredicted x PAL(HR) and BMRpredicted x PALq respectively, average results were in agreement with TEEref. Furthermore, TEE values based on BMRpredicted and PALacc, PAL(HR), PALq as well as on PAL = 1.64, minus TEEref, were significantly correlated with body fatness. When the same PAL value (1.64) was used for all subjects, this correlation was particularly strong. Thus, the World Health Organization (1985) procedure may give TEE results that are biased with respect to the body fatness of subjects.

Subnotificação da ingestão energética na avaliação do consumo alimentar

Informações válidas sobre o consumo de energia e nutrientes são um pré-requisito em muitas pesquisas de nutrição humana, principalmente nos estudos epidemiológicos sobre dieta e saúde. Até o advento da água duplamente marcada, não era possível validar as avaliações do consumo energético de forma externa e independente. Este marcador demonstrou a existência de significativa subnotificação da ingestão energética. Esta pesquisa objetiva discutir os principais aspectos relacionados a tal fenômeno: prevalência, determinantes, especificidade de nutrientes e formas de controle. O sub-relato parece estar associado à obesidade e a características psicossociais, como a restrição dietética e o desejo de ajuste social. Todos os métodos de avaliação do consumo possuem erros inerentes, sendo portanto suscetíveis à sub ou superestimação (menos comum). O sub-relato demonstra atingir predominantemente alimentos específicos, ricos em lipídeos e carboidratos, o que insere grande viés nas inferências baseadas em levantamentos do consumo alimentar. Este artigo também discute como controlar tal erro e recomenda que as estimativas do consumo energético sejam confrontadas com o gasto energético, a fim de detectar a subnotificação.

Assessment of factors affecting the validity of self-reported health-risk behavior among adolescents: evidence from the scientific literature

We reviewed the existing empirical literature to assess cognitive and situational factors that may affect the validity of adolescents' self-reports of alcohol and other drug use, tobacco use, behaviors related to unintentional injuries and violence, dietary behaviors, physical activity, and sexual behavior. Specifically, we searched for peer-reviewed journal articles published in 1980 or later that examined the factors affecting self-report of the six categories of behavior listed above. We also searched for studies describing objective measures for each behavior. Self-reports of each of six types of health-risk behaviors are affected by both cognitive and situational factors. These factors, however, do not threaten the validity of self-reports of each type of behavior equally. The importance of assessing health-risk behaviors as part of research activities involving adolescents necessitates the use of self-report measures. Researchers should familiarize themselves with the threats to validity inherent in this type of assessment and design research that minimizes these threats as much as possible.

Selective underreporting of energy intake in women: magnitude, determinants, and effect of training

OBJECTIVE

The aim of this study was to quantify underreporting of energy intake in Brazilian women; identify underreporting determinants; find out if underreporting was selective and; test if a motivational multimethod training, in combination with providing the subjects some results from the prior recording period, was able to reduce underreporting.

DESIGN

Energy intake (EI) was assessed by a 7-day diet record. Energy expenditure (EE) was calculated by heart rate monitoring. EI:EE ratio lower than one in subjects who did not lose weight in one month was considered underreporting. Underreporting was correlated with anthropometric, behavioral, and psychological parameters. Food and nutrient consumption was compared between underreporters and non-underreporters. A focus group investigated the main causes of underreporting. Subjects were told that the earlier food records' results were unrealistic and submitted to a motivational training. Then, they were reevaluated for underreporting.

SUBJECTS

Subjects were recruited by advertisements for a physical activity program. Thirty-eight healthy women, 13 normal-weight (34%), 13 overweight (34%), and 12 obese (32%), enrolled in the study. Three subjects (2 normal-weight and 1 obese) (8%) withdrew.

STATISTICAL ANALYSIS PERFORMED

Analysis of variance, paired t tests, and simple linear regression.

RESULTS

Seventeen women (49%) underreported their EI by 21%. A significant negative correlation was found between social desirability and EI:EE. Undereating, errors in portion sizes estimation and the inconvenience of having to record everything that was eaten seemed to explain underreporting. Mean portion sizes did not differ for underreporters and non-underreporters. Fewer self-reported years of education was correlated with underreporting only among normal-weight women. Training and confrontation with earlier results reduced underreporting rate to 33%, but did not affect macronutrient densities. Applications/conclusions Subjects tended to report their intake in a socially desirable way, by eating or reporting less frequently foods considered unhealthful or fattening, like sweets and fried foods. Inclusion of social desirability score as a covariate in studies that rely on self-reports of food intake may be useful. A motivational training program, developed in such a way that subjects are comfortable reporting intake of foods considered socially undesirable, in combination with confrontation with earlier results of dietary assessment and use of portion size measurement aids, can be used to attenuate underreporting.

Methodology of dietary assessment in athletes: concepts and pitfalls

PURPOSE OF REVIEW

Evaluation of an athlete's diet is important in both clinical practice and research. The main purpose of this review is to provide health professionals with guidance regarding the special issues that are likely to be encountered when assessing the dietary intake of sportspersons.

RECENT FINDINGS

A number of methods may be used for the dietary assessment of individuals and/or groups of athletes, including retrospective (diet recall, food-frequency questionnaire, and diet history) and prospective (diet record, duplicate portion) techniques. A 3-4-day estimated diet record is the most widely used approach, but collection of single or multiple diet recalls is also common. Care must be taken, however, to ensure that days of diet monitoring accurately reflect usual food consumption during the period of interest. Under-reporting of habitual energy intake is widespread among athletes, and its magnitude should be carefully addressed when interpreting the results of dietary assessment. Other issues, specifically related to sportspersons, that are often neglected include adequacy of standard portion sizes, frequency of snacking, fluid intake, supplement use, weight-control practices, and seasonality of sport activities and food consumption.

SUMMARY

There are subtle methodological differences in the dietary assessment of athletes and non-athletes, which, when taken into consideration, may substantially increase the quality of intake data and optimise the outcome of dietary intervention.

Personality characteristics as predictors of underreporting of energy intake on 24-hour dietary recall interviews

OBJECTIVE

To identify characteristics associated with misreporting of energy intake during 24-hour dietary recalls (24 HR).

DESIGN

Ninety-eight subjects were administered two 24 HRs. Energy expenditure was determined by doubly labeled water (44 subjects) or intake balance (54 subjects). Data on subjects' physical, lifestyle, and psychosocial characteristics were also collected. Subjects/setting At the Beltsville Human Nutrition Research Center 52 women and 46 men were administered 24HR and completed lifestyle and personality questionnaires and a memory test. Physical characteristics such as weight, percent body fat, and total energy expenditure were measured. Statistical analysis The influences of subject parameters on energy misreporting were assessed by linear regression and Pearson product-moment correlation analysis for continuous variables and by ANOVA for discrete variables. Stepwise regression was used to identify key factors in underreporting.

RESULTS

Factors particularly important in predicting underreporting of energy intake include factors indicating dissatisfaction with body image; for example, a 398 kcal/day underreport in subjects attempting weight loss during the past year with a nearly 500 kcal/day underreport in women. Overall, women underreported by 393 kcal/day relative to men and women evinced a social desirability bias amounting to a 26 kcal underreport for each point on the social desirability scale. Gender differences also were evident in the effect of percent body fat (with men underreporting about 16 kcal/day/percent body fat) and in departure from self-reported ideal body weight (with women underreporting about 21 kcal/day/kg).

APPLICATIONS/CONCLUSIONS

Body image and fatness are key factors on which health professionals should focus when seeking predictors of underreporting of dietary intake. Dietary interviews must be conducted to minimize bias related to subjects' tendencies to win approval and avoid censure by the interviewer. In addition, dissatisfaction with body image may lead to underestimation of food intake, therefore reducing likelihood of success in weight loss. Thus, health care professionals involved in weight loss counseling may achieve better success if treatment includes generating a more positive body image.

Associations between diet and the metabolic syndrome vary with the validity of dietary intake data

BACKGROUND

Underreporting is a common problem in dietary surveys. Few studies have shown the implication of this when investigating diet-disease relations.

OBJECTIVE

We investigated how underreporting affects the associations between dietary factors and the metabolic syndrome.

DESIGN

Dietary intake measured with a 7-d food record, fasting insulin concentrations, and other variables of the metabolic syndrome were assessed in a cross-sectional study of 301 healthy men aged 63 y. Biological markers for intakes of protein, sodium, and potassium were measured in 24-h urine samples. Underreporters (URs, n = 88) were identified by Goldberg's equation, which compares energy intake with energy expenditure, both expressed as multiples of the basal metabolic rate. Physical activity level was estimated, and individual cutoffs were calculated.

RESULTS

The URs had higher nutrient and food densities in their diet than did the non-URs, which suggested that they followed a healthier diet. The URs had a higher prevalence of the metabolic syndrome than did the non-URs (18% and 9%, respectively; P = 0.029). The biological markers confirmed a low validity of the dietary data in the URs. The correlations between fasting insulin concentrations, a central component of the metabolic syndrome, and the intakes of polyunsaturated fats, n-6 fats, and fat from milk products were stronger in the URs than in the non-URs, which indicates that inaccurate data can introduce spurious associations.

CONCLUSION

The association between diet and fasting insulin differed between URs and non-URs in this study of 301 healthy men aged 63 y. If URs are not identified and excluded or treated separately in studies in nutritional epidemiology, spurious diet-disease relations may be reported.

Risk of suboptimal iron and zinc nutriture among adolescent girls in Australia and New Zealand: causes, consequences, and solutions

Surveys in Australia, New Zealand and other industrialised countries report that many adolescent girls have dietary intakes of iron and zinc that fail to meet their high physiological requirements for growing body tissues, expanding red cell mass, and onset of menarche. Such dietary inadequacies can be attributed to poor food selection patterns, and low energy intakes. Additional exacerbating non-dietary factors may include high menstrual losses, strenuous exercise, pregnancy, low socioeconomic status and ethnicity. These findings are cause for concern because iron and zinc play essential roles in numerous metabolic functions and are required for optimal growth, immune and cognitive function, work capacity, sexual maturation, and bone mineralization. Moreover, if adolescents enter pregnancy with a compromised iron and zinc status, and continue to receive intakes of iron and zinc that do not meet their increased needs, their poor iron and zinc status could adversely affect the pregnancy outcome. Clearly, intervention strategies may be needed to improve the iron and zinc status of high risk adolescent subgroups in Australia and New Zealand. The recommended treatment for iron deficiency anaemia and moderate zinc deficiency is supplementation. Although dietary intervention is often recommended for treating non-anaemic iron deficiency and mild zinc deficiency, it is probably more effective and appropriate for prevention than for the treatment of suboptimal iron and zinc status. Many of the strategies for enhancing the content and bioavailability of dietary iron are also appropriate for zinc.

Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents

OBJECTIVES

To compare the effects of a low-carbohydrate (LC) diet with those of a low-fat (LF) diet on weight loss and serum lipids in overweight adolescents.

DESIGN

A randomized, controlled 12-week trial.

SETTING

Atherosclerosis prevention referral center.

METHODS

Random, nonblinded assignment of participants referred for weight management. The study group (LC) (n = 16) was instructed to consume <20 g of carbohydrate per day for 2 weeks, then <40 g/day for 10 weeks, and to eat LC foods according to hunger. The control group (LF) (n = 14) was instructed to consume <30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks. Serum lipid profiles were obtained at the start of the study and after 12 weeks.

RESULTS

The LC group lost more weight (mean, 9.9 +/- 9.3 kg vs 4.1 +/- 4.9 kg, P <.05) and had improvement in non-HDL cholesterol levels (P <.05). There was improvement in LDL cholesterol levels (P <.05) in the LF group but not in the LC group. There were no adverse effects on the lipid profiles of participants in either group.

CONCLUSIONS

The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile.

Leptin and energy metabolism in pulmonary tuberculosis

BACKGROUND

Pulmonary tuberculosis is the classic cause of "consumption," but the pathogenesis of such wasting is largely unknown. Animal studies in other conditions suggest that leptin may be a mediator between proinflammatory cytokine activity and wasting.

OBJECTIVE

We tested whether the leptin concentration, after control for body fat mass, is higher during active pulmonary tuberculosis than after recovery and whether it correlates with energy metabolism and proinflammatory cytokine activity.

DESIGN

Nondiabetic adults with pulmonary tuberculosis (n = 32) were recruited into a prospective observational study. Patients found to be antibody positive for human immunodeficiency virus were excluded from the study. Dual-energy X-ray absorptiometry, indirect calorimetry, and food intake protocols were performed at baseline and after 1 and 6 mo of tuberculosis treatment. Fasting plasma leptin, tumor necrosis factor alpha and its soluble receptor, and interleukin 6 were measured by enzyme-linked immunosorbent assay.

RESULTS

Resting energy expenditure was close to Harris-Benedict predictions and did not change significantly during treatment, but energy intake increased. Leptin concentration was correlated in a log-linear fashion with percentage body fat but was independent of cytokines and energy intake. There was no significant difference in leptin, corrected for energy balance and fat mass, at baseline and after 1 and 6 mo of treatment.

CONCLUSIONS

These data are compatible with recovery from anorexia or starvation without discernible hyper- or hypometabolism. The close correlation of leptin with body fat mass is similar to observations in healthy subjects. No additional influence of disease state or proinflammatory cytokine activity was found. Leptin does not appear to be a component of the immune response to human pulmonary tuberculosis, and thus it cannot account for the weight loss and anorexia associated with tuberculosis.

Fruit and vegetable assessment: performance of 2 new short instruments and a food frequency questionnaire

OBJECTIVE

To evaluate the ability of 2 new short assessment instruments and a food frequency questionnaire (FFQ) to measure intake of fruit and vegetables. The "All-Day" screener asks frequency and portion size questions about 9 food items. The "By-Meal" screener is similar, except that it asks about 2 of those 9 food items in terms of mealtime.

DESIGN

Survey participants completed 4 telephone-administered 24-hour dietary recalls over 1 year, a self-administered FFQ 1 to 2 months later, and 1 of 2 self-administered screeners after an additional 7 months.

SUBJECTS/SETTING

Participating were 202 men and 260 women aged 20 to 70 years living throughout the United States.

STATISTICAL ANALYSES

Fruit and vegetable intakes measured by each screener and the FFQ were compared with true usual intake based on a measurement error model with 24-hour dietary recalls as the reference instrument.

RESULTS

Estimates of median daily servings of fruit and vegetables were as follows: For men: True intake (5.8) vs All-Day screener (5.0), By-Meal screener (5.5), and FFQ (6.6); for women: true intake (4.2) vs All-Day screener (5.0), By-Meal screener (5.4), and FFQ (6.2). Estimated correlations between the test instruments and true intake were as follows: For men: All-Day screener (0.66), By-Meal screener (0.67), FFQ (0.68); for women: All-Day screener (0.51), By-Meal screener (0.53), and FFQ (0.54).

APPLICATIONS/CONCLUSIONS

Both screeners might be useful to estimate median intakes of fruit and vegetable servings in US populations, but they might be less useful in accurately ranking individuals. More research is needed before using the screeners in ethnic or low-literacy populations.

Energy intake and energy expenditure in elite lightweight female rowers

PURPOSE

The training program undertaken by many athletes will affect directly the total, habitual energy requirements of that individual. Unless that energy requirement is met via the diet and or supplementation, chronic negative energy balance will ensue, which will have both short-term and long-term effects not only on performance but also on general health. The aim of this research was therefore to determine the energy expenditure (EE) and hence energy requirements of lightweight female rowers and, further, to compare this with their self-reported energy intake (EI).

METHODS

The EI of seven lightweight female rowers was measured using a self-reported 4-d weighed dietary record. EE was determined using the doubly labeled water (DLW) technique over a 14-d period.

RESULTS

The mean (+/-SD) age, height, and weight of the subjects was 20 (+/-1.1) yr, 168.8 (+/-4.7) cm, and 60.9 (+/-2.3) kg, respectively. The rowers self-reported EI was 2,214 (+/-313) kcal x d(-1) and their total EE was 3,957 (+/-1,219) kcal x d(-1). After adjusting total EE for changes in body weight (mean (+/-SD) -1.2 (+/-1.2) kg), the comparison between adjusted EI and reported showed a bias to underreporting of 1,133 (+/-1,539) kcal x d(-1) or 34%. The bias was not consistent across adjusted EI, and two of the seven subjects overreported their intake.

CONCLUSIONS

Due to the underreporting of EI, diet recording may not be an appropriate way of assessing energy requirements in lightweight female rowers. A benefit of accurately determining energy requirements, as with DLW, is that female lightweight rowers will be able to successfully manipulate their EI and achieve the set weight cut-off for participation without compromising their health or performance.

Validity of the assessment of dietary intake: problems of misreporting

PURPOSE OF REVIEW

This is a review of recent studies on the analysis of misreporting of food intake and on the consequences of misreporting for the interpretation of dietary surveys. Bias in the assessment of dietary intake was analysed from studies comparing reported intake with doubly labelled water assessed energy expenditure.

RECENT FINDINGS

There is not yet a method for the accurate determination of dietary intake. Physical and psychological characteristics of study participants play an important role in the observed reporting bias. The degree of misreporting might increase with repeated dietary assessment in the same subjects, confounding the results of intervention studies.

SUMMARY

Campaigns aimed at changing food intake might not be as successful as concluded from the results of national food consumption measurements. Subjects might be reporting according to expected instead of real intake. In a clinical setting, the increased awareness of the nursing staff has been observed to result in overreporting of intake.

Antioxidant vitamins in the prevention of cardiovascular disease: a systematic review

Do antioxidant vitamins, in regular food or as food supplements, protect against myocardial infarction and stroke? In this systematic literature review on the effects of antioxidant vitamins in the primary prevention of cardiovascular disorders, studies with ischaemic heart disease, stroke or combined cardiovascular events as end-points have been included. Studies on the effects of antioxidant vitamins on intermediary end-points (such as blood lipids and blood pressure) and as secondary prevention in patients with manifest cardiovascular disease are reviewed in a conventional manner. In observational studies (case-control or cohort design), people with high intake of antioxidant vitamins by regular diet or as food supplements generally have a lower risk of myocardial infarction and stroke than people who are low-consumers of antioxidant vitamins. The associations in observation studies have been shown for carotene, ascorbic acid as well as tocopherol. In randomized controlled trials, however, antioxidant vitamins as food supplements have no beneficial effects in the primary prevention of myocardial infarction and stroke. Serious adverse events have been reported. After an initial enthusiasm for antioxidants in the secondary prevention of cardiovascular disease, recent reports from of several large randomized trials have failed to show any beneficial effects. Thus, the apparent beneficial results of high intake of antioxidant vitamins reported in observational studies have not been confirmed in large randomized trials. The discrepancy between different types of studies is probably explained by the fact that supplement use is a component in a cluster of healthy behaviour. Antioxidant vitamins as food supplements cannot be recommended in the primary or secondary prevention against cardiovascular disease.