Issues in the measurement of energy intake for free-living human populations

Modeling body mass variation: incorporating social influence into calculations of caloric intake and energy expenditure

Variations in individual body mass and composition have long been a key focus in the health sciences, particularly now that overweight and obesity are considered as public health problems. We study a mathematical model that describes body mass variations which are determined by the energy balance between caloric intake and total energy expenditure. To calculate the change in caloric intake and energy expenditure over time, we proposed a relationship for each of these quantities, and we used measured values that are reported in the literature for the initial conditions. To account for small variations in the daily energy balance of an individual, we include social interactions as the multiplication of two terms: social proximity and social influence. We observe that social interactions have a considerable effect when the body mass of an individual is quite constant and social interactions take random values. However, when an individual's mass value changes (either increases or decreases), social interactions do not have a notable effect. In our simulation, we tested two different models that describe the body mass composition, and it resulted that one fits better the data.

Socioeconomic status and body size among women in Honduran Miskito communities

BACKGROUND

This study investigates evidence of the nutrition transition among women in Miskito communities on the northeastern coast of Honduras.

AIM

The hypothesis that socioeconomic status (SES) is positively associated with body size and fatness is tested; and dietary and physical activity patterns are examined among SES groups.

SUBJECTS AND METHODS

An anthropometric survey was conducted with 200 non-pregnant women following standard procedures. Dietary intake and physical activity data were collected using 24-hour recall methods. Women were categorized into three SES groups (high, medium and low) based on economic and social attributes. Differences in anthropometric measures, diet and physical activity among SES groups were analysed.

RESULTS

More than 70% (n = 142) of women in the sample were overweight or obese. Mean height, weight, skin-fold thicknesses, arm and calf circumferences, percentage body fat and upper-arm fat area were significantly greater among high SES women than low SES women. Women with high SES had lower rates of physical activity and higher rates of obesity, perceived food sufficiency, meat consumption, milk/dairy intake and general dietary diversity.

CONCLUSION

High SES women were significantly fatter than low SES women; and variation observed among groups is likely related to different patterns of dietary intake and physical activity.

Cultural and environmental barriers to adequate iron intake among northern Kenyan schoolchildren

The purpose of this study was to examine the context of iron deficiency and feeding patterns of iron-rich foods among northern Kenyan school-aged children. A nutrition survey was conducted among 300 subjects in two Rendille communities, Korr and Karare. The objectives were to determine the prevalence of iron deficiency as it relates to parasitic infection, dietary intake, and sociodemographic factors, as well as cultural food proscriptions influencing child feeding. Sociodemographic and qualitative data on food beliefs and child-feeding practices were obtained from the primary caretaker of each subject. From pediatric subjects, 24-hour dietary recall data were obtained with the help of the primary caretaker, and capillary blood from a fingerstick was used to detect iron deficiency based on measures of hemoglobin, the zinc protoporphyrin-to-heme ratio, C-reactive protein, and transferrin receptor. With an overall prevalence of 31.2%, iron deficiency was found to be associated with dietary iron intakes constrained by diverse economic, cultural, and environmental factors among Rendille children. In Karare, where children's iron intake approached recommended levels, iron deficiency was found to be attributable to low bioavailability of iron (only 4.3% of total iron intake), rather than low dietary intake per se. By contrast, in Korr the average daily iron intake was estimated at only 65% of recommended allowances, indicating that iron deficiency was the outcome not merely of low bioavailability, but rather of overall inadequate iron intake. Sociodemographic analysis showed a significant interaction between sex and economic status, revealing that girls in economically sufficient households were 2.4 times as likely to have iron deficiency as boys. This difference in risk parallels culturally defined gender-based proscriptions for child feeding: girls are believed to benefit from "soft foods," including rice, maize porridge, and tea, whereas boys benefitfrom "hard foods," including meat, blood, and beans. Consequently, in households economically able to purchase iron-rich foods, these foods are being preferentially fed to boys. Economic development may result in improved iron status for boys, but it will be unlikely to benefit girls in the absence of a dietary modification intervention. A modification of culturally acceptable "soft foods" to include iron-rich foods may provide a sustainable approach to controlling and preventing iron deficiency in this population.

The maternal depletion transition in northern Kenya: the effects of settlement, development and disparity

Maternal depletion syndrome, defined as a broad pattern of maternal malnutrition resulting from the combined effects of dietary inadequacy, heavy workloads, and energetic costs of repeated rounds of reproduction, has been determined to be an important predictor of maternal and child health. Debates regarding the existence of maternal depletion syndrome have centred on the inability to identify a single universal pattern of parity-related depletion. However, it is becoming increasingly apparent that patterns of depletion may be linked to overall dietary adequacy and conditioned by socioeconomic development. Therefore, variable patterns of maternal depletion are useful for examining changing patterns of women's nutrition in the process of development. This study examines the nutritional status and dietary intakes of 912 Rendille women in one nomadic and four settled communities in northern Kenya, and tests the assertion that settlement of former nomadic pastoralists results in improved diet and nutrition. Both long-term and short-term reproduction-related changes in BMI, triceps skin fold and upper arm muscle area are examined in relation to parity, age, and socioeconomic factors. Overall community comparisons reveal improvements in dietary adequacy and nutritional status only among women residing in the District capitol, Marsabit. Women in small settlements and the nomadic community, by contrast, display patterns of long-term chronic energy deficiency that obscure short-term reproduction-related energy costs. In addition, data reveal that economic disparity increases in the process of settlement and development and that low socioeconomic status negatively influences dietary intake and nutritional well being. The findings highlight the importance of examining variation within and between communities for understanding the complex nature of the maternal depletion transition.

Macronutrient energy intake and adiposity in non obese prepubertal children aged 5-11 y (the Fleurbaix Laventie Ville Santé Study)

OBJECTIVE

To investigate associations between adiposity indices and food intake in nonobese prepubertal free-living children.

SUBJECTS

Five-hundred and one children, 280 boys and 221 girls aged 5-11 y in two little towns in northern France.

DESIGN

Cross-sectional survey.

MAIN OUTCOME MEASURES

Height and weight, four skinfolds (biceps, triceps, subscapular, suprailiac), waist and hip girths, were measured. Sum of skinfolds (SSF), body mass index (BMI), and relative weight (RW) were calculated. Energy intake (EI), percentage of energy intake ascribed to carbohydrates (%EIC), complex carbohydrates (%EICC), fats (%EIF), saturated fats (%EISF) and proteins (%EIP) were assessed by a single 24 h record. Basal metabolic rate (BMRI was estimated according to Schofield's equations. Obese (RW > or = 120%), and underreporting children according to Goldberg's and Black's equations were excluded.

RESULTS

In multiple linear regressions analyses performed with hierarchical mixed models, adiposity indices were significantly and inversely associated in girls with %EIC (all P-values < 0.02), and positively with %EIF (all P-values < 0.05, waist girth and BMI excepted). Similar but non-significant trends were observed in boys. The relationships were not linear, and thresholds close to current dietary recommendations were highlighted. When %EIF was low, a lower percentage of energy intake ascribed to %EISF was associated with thinness. These associations remained after the exclusion of children who had an EI/BMR > or = 1.50.

CONCLUSIONS

In nonobese prepubertal children aged 5-11 y, a high %EIC, close to dietary recommendations (> or = 55%), was associated with thinness. A high %EIF, over the upper dietary recommendation (< or = 35%), was associated with a greater adiposity thickness. There was no further increase in adiposity beyond this threshold. Reasons for the absence of a linear relationship pattern between adiposity and macronutrient intake remain to be determined.

Estimating energy intake of urban women in Colombia: comparison of diet records and recalls

As part of a larger study of energy-nutrition, we compared the performance of 24 h diet recalls with estimated diet records kept by trained observers. The subjects were economically disadvantaged women (n = 85) in the city of Cali, Colombia. A 24 h recall and an estimated diet record were collected for each woman at 0 and approximately 3 and 6 months. Energy intake obtained from the estimated dietary records was validated against energy expenditure and used as the reference method. Energy and macronutrient intake were calculated from published food composition tables and proximate analyses of common foods. The number of food items consumed per woman per day, total and in each of 16 food groups, was tabulated. Energy and macronutrient intakes were 11-13% lower in the 24 h recalls. The discrepancy energy could be largely accounted for by the lower number of food items in the recalls. The number of food items in eight of 16 food groups was significantly lower in the recalls compared to the records. Underreporting on the recalls was a general tendency in these subjects and not clearly related to average energy intake. We conclude that 24 h diet recalls underestimate energy and nutrient intake in this population and are not suitable for studies of human energetics.

Seasonal and sex variation in physical activity levels among agro-pastoralists in Nepal

Considerable attention has been devoted to variation in levels of energy expenditure between and within populations; these are commonly evaluated following international guidelines for grading light, moderate, and heavy physical activity levels (PAL). This study presents activity profiles by season and sex for subsistence agro-pastoralists in Nepal, comparing data for a sample of 20 men observed four times across the year with previously published data on women. Total energy expenditure (TEE) was estimated from direct minute-by-minute observation (totaling 1,679 h for men, 3,601 h for women) and measures of the energy cost of single tasks (117 for men, 168 for women). PAL were calculated and graded as multiples of predicted basal metabolic rate (BMR). Despite an explicitly egalitarian organization of labor, men achieved higher PAL than women (P <.0001), although according to international gradings, both men and women assume moderately heavy PAL in the winter and very heavy PAL in the monsoon. PAL were 1.88 and 2.22 x BMR for men in respective seasons (P <.005; TEE, 11.8 MJ/d and 13.9 MJ/d) and 1.77 and 2.0 x BMR for women (TEE, 9.1 MJ/d and 10.5 MJ/ d). High TEE values result from time-consuming work in subsistence tasks, most of which are of moderate energy cost. Results show that the international guideline (FAO/WHO/UNU [1985]) for grading levels of energy expenditure, which adopts discrepant sex-specific values to define thresholds for moderate or heavy PAL, can mask significant gender variation. Male/female ratios of PAL values are suggested instead for population-level comparisons.