Under-reporting of food intake is frequent among Brazilian free-living older persons: a doubly labelled water study.

The assessment of food intake is essential for the development of dietetic interventions. Accuracy is low when intake is assessed by questionnaires, the under-reporting of food intake being frequent. Most such studies, however, were performed in developed countries and there is little data about the older population of developing nations. This study aimed to verify the total energy expenditure (TEE) of independent older Brazilians living in an urban area, through the doubly labelled water (DLW) method and to compare it with the reported energy intake obtained through the application of a food frequency questionnaire (FFQ). Initially, 100 volunteers aged from 60 to 75 years had their body composition determined by dual-energy X-ray absorptiometry (DEXA). Five volunteers of each quartile of body fat percentage had their energy expenditure determined by DLW. The mean age of the subjects included in this phase of the study was 66.4 +/- 3.5 years, and ten of the subjects were men. The mean TEE was 2565 +/- 614 and 2154 +/- 339 kcal.day(-1) for men and women, respectively. The Physical Activity Level (PAL) was 1.58 +/- 0.31 and 1.52 +/- 0.22, respectively. Under-reporting of food intake was highly prevalent, with a mean percentage of reported intake in relation to measured TEE of -17.7%. Thus, under-reporting of food intake is highly prevalent among Brazilian independent older persons. The DLW method is an important tool in nutritional studies and its use is to be recommended in developing countries.

Energy expenditure of stunted and nonstunted boys and girls living in the shantytowns of São Paulo, Brazil.

BACKGROUND: Stunting increases the risk of obesity in developing countries, particularly in girls and women, but the underlying reason is not known. OBJECTIVE: Our objective was to test the hypothesis that stunted children have lower energy expenditure than do nonstunted children, a factor that has predicted an increased risk of obesity in other high-risk populations. DESIGN: A cross-sectional study was conducted in shantytown children from São Paulo, Brazil. Twenty-eight stunted children aged 8-11 y were compared with 30 nonstunted children with similar weight-for-height. Free-living total energy expenditure (TEE) was measured over 7 d by using the doubly labeled water method. In addition, resting energy expenditure (REE) was measured by indirect calorimetry and body composition was measured by dual-energy X-ray absorptiometry. RESULTS: There were no significant associations between stunting and any measured energy expenditure parameter, including REE adjusted for weight (f1.gif" BORDER="0"> +/- SEM: 4575 +/- 95 compared with 4742 +/- 91 kJ/d, in stunted and nonstunted children, respectively) and TEE adjusted for weight (8424 +/- 239 compared with 8009 +/- 221 kJ/d, in stunted and nonstunted children, respectively). In multiple regression models that included fat-free mass and fat mass, girls had significantly lower TEE than did boys (P: < 0.05) but not significantly lower REE (P: = 0.17). CONCLUSIONS: There was no association between stunting and energy expenditure after differences between groups in body size and composition were accounted for. However, the girls had lower TEE than did boys, which may help to explain the particularly high risk of obesity in stunted adolescent girls and women in urban areas of developing countries.

Deuterium oxide as a tracer for measurement of compliance in pediatric clinical drug trials.

We tested the hypothesis that a deuterium oxide (D2O) tracer could discriminate among patterns of clinically significant, imperfect compliance during drug trials. A model was developed to predict deuterium concentration during multiple dose regimens. After developing a regression equation to predict one of the model parameters for children, we selected healthy children (N = 20) at random to receive one of five 10-day D2O regimens. Five urine samples were obtained from each child during 15 days and analyzed for deuterium level by mass spectrometry. Each child's height, weight, age, and the first four urinary deuterium levels were used to estimate the amount and timing of deuterium administration. These estimates were compared with the five regimens to determine the closest match between estimate and regimen. The closest matching regimen was the regimen actually administered to 19 (95%) of the 20 children. Two of these children had D2O administration estimates that could be confused with another regimen. The correlation between the model's predicted levels and the measured levels of all urine samples was 0.96. We conclude that a D2O tracer shows excellent promise as a quantitative method of assessing compliance with liquid medications under specified conditions.