Carla R. Fjeld

Total body water measured by 18O dilution and bioelectrical impedance in well and malnourished children

ABSTRACT: Total body water (TBW) is an indicator of fat-free mass and thus of nutritional status but cannot be measured readily in children in developing countries who are at greatest risk of becoming malnourished. We therefore developed equations to predict 18O TBW from bioelectrical impedance (Z), wt, and ht in well and malnourished infants and children whom we considered characteristic of children evaluated in nutritional surveillances in Peru. Children 3 to 30 mo of age, whose wt were 3.4 to 14.4 kg, which was —2.8 to +1 SD wt-for-ht, were randomly assigned to group I (n = 30) to develop equations to predict TBW or to group II (n = 14) to cross-validate the predictive equations. Mean TBW measured by 18O dilution was 4.8 ± 1.2 kg in group I, and 5.6 ± 1.7 kg in group II. TBW ranged from 57 to 78% of body wt (65 ± 6%) in group I and from 56 to 80% (64 ± 6%) in group II, indicating no statistically significant differences in body composition. The following equation was developed and cross-validated: TBW, kg = 0.48 + 0.68 ht2/Z; standard error estimate = 0.36; r = 0.98). A slight improvement was achieved by the addition of body wt (TBW, kg = 0.76 + 0.18 ht2/Z + 0.39 wt; standard error estimate = 0.23; r = 0.99).

A new model for predicting energy requirements of children during catch-up growth developed using doubly labeled water.

ABSTRACT: Energy partitioned to maintenance plus activity, tissue synthesis, and storage was measured in 41 children in early recovery [W/L (wt/Iength)<5th percentile] from severe protein-energy malnutrition and in late recovery (W/L = 25th percentile) to determine energy requirements during catch-up growth. Metabolizable energy intake was measured by bomb calorimetry and metabolic collections. Energy expended (x± SD) for maintenance and activity estimated by the doubly labeled water method was 97 ± 12 kcal/kg FFM (fat-free mass) in early recovery and 98 ± 12 kcal/kg FFM in late recovery (p>0.5). Energy stored was 5-6 kcal/g of wt gain. Tissue synthesis increased energy expenditure by 1 ± 0.7 kcal/g gain in both early and late recovery. From these data a mathematical model was developed to predict energy requirements for children during catch-up growth as a function of initial body composition and rate and composition of wt gain. The model for predicting metabolizable energy requirements is [(98 x FFM + A (11.1 B + 2.2 C)], kcal/ kg.d, where FFM is fat-free mass expressed as a percentage of body wt, A is wt gain (g/kgd), B and C are percentage of wt gain/100 as fat and FFM, respectively. The model was tested retrospectively in separate studies of malnourished children.

Protection of Vitamin A Status in Chinese Children by a Dietary Intervention with Vegetables

A study of seasonal fluctuation of serum vitamin A concentrations in children in northern China showed that the prevalence of low serum levels of vitamin A was due to seasonal changes in the intakes of carotenoids. to determine whether plant carotenoids could sustain or improve childrens vitamin A status during the fall and winter seasons, we performed an intervention with vegetables starting in the fall in Shandong, China. At a kindergarten, the serum vitamin A concentration was less than 1.05 μmol/L in 39% of the children. for five days per week for 10 weeks, 22 children were each provided with approximately 238 g/day of green and yellow vegetables and 34 g/day of light-coloured vegetables. Nineteen children maintained their customary dietary intake in the fall season, which included 56 g/day of green and yellow vegetables and 224 g/day of light-coloured vegetables. Vitamins A-d8 and Ad4 were given before and after the interventions, respectively, and their enrichments in the circulation were determined by gas chromatography/mass spectrometry to investigate vitamin A body stores. the serum concentration of β-carotene improved in the group fed mainly green and yellow vegetables but decreased in the group fed mainly light-coloured vegetables. the serum concentration of retinol was sustained in the group fed mainly green and yellow vegetables but decreased in the group fed mainly light-coloured vegetables (p < .01). the isotope dilution tests confirmed that total body stores of vitamin A were sustained in the group fed mainly green and yellow vegetables but decreased by 27 μmol (7,700 μg), on average, per child in the group fed mainly light-coloured vegetables (p < .06). Dietary green and yellow vegetables can provide adequate vitamin A nutrition to kindergarten children and protect them from becoming vitamin A deficient during seasons when the provitamin A food source is limited.

Control of protein synthesis and its relationship to the bioenergetics of growth

A key goal of nutritional therapies designed to prevent or treat protein energy malnutrition (PEM) is achievement of adequate growth rates and thus positive balances of protein and energy. Positive protein balance is the net result of protein turnover, i.e., of recycling protein through energy‐requiring anabolic and catabolic pathways. Thus, protein turnover is inexorably linked to energy metabolism and to energy balance. A long‐standing hypothesis is that new tissue synthesis is predominantly a postprandial event. Thus, postprandial rates of protein turnover may regulate the bioenergetics of growth. Traditional methods to evaluate nutritional therapies for diarrhea and PEM, i.e., metabolic balance, 15N‐labeled amino acids, fecal output, illness duration, or change in body weight, are not specific to studies of the regulation of acute protein turnover and growth by nutritional intervention. Newer techniques based on 13C‐labeled amino acids should be applied to evaluate nutritional interventions such as dietary substrate ratios, protein quality, feeding frequencies, or ratios of dietary protein to energy in terms of their abilities to optimize postprandial protein turnover and thus nutritional management of diarrhea or PEM.