Biomedical subjects

J E Stuff

Publications and source records attributed to J E Stuff.

25 records · Page 2Linked to original sources

PubMed1993

Calcium absorption and metabolism in children with juvenile rheumatoid arthritis assessed using stable isotopes.

OBJECTIVE: To assess calcium intake, absorption, urinary excretion and the fraction of urinary calcium originating from bone and diet in patients with juvenile rheumatoid arthritis (JRA). METHODS: A dual tracer stable isotope technique was used to study 6 girls and 3 boys with JRA. RESULTS: Fractional absorption in the 6 girls, ages 4-9, with JRA was significantly lower than that in 10 similar, healthy girls (22.6 +/- 4.7% vs 30.4 +/- 8.4%, p = 0.033). Urinary calcium excretion tended to be higher in the girls with JRA than in controls, (2.9 +/- 1.5 vs 1.6 +/- 1.7, p = 0.15). The urinary calcium in patients with JRA was derived principally from bone, and there was no increase in diet derived urinary calcium. One of the boys with new onset JRA was markedly hypercalciuric and in negative calcium balance (-222 mg/day). CONCLUSION: Our data show that hypercalciuria in patients with JRA results from bone resorption, not hyperabsorption of dietary calcium and suggest that increases in calcium intake may benefit children with JRA.

Adolescent↗

PubMed1991

Energy requirements of breast-fed infants.

Current recommendations for energy intake are reviewed in light of emerging data on energy intakes of breast-fed infants and on total daily energy expenditure of infants. For determination of energy requirements, the historical approach based on observed intakes of healthy infants is compared with a newly proposed approach based on energy expenditure and deposition. A data set of exclusively breast-fed infants is used to illustrate the circuity of either approach. Energy intake, expenditure, and stores must be evaluated in an assessment of dietary adequacy. Ultimately, energy requirements of infants should reflect growth rate, body composition, and level of physical activity conducive to optimal health and neurobehavioral development.

Basal Metabolism↗

PubMed1989

Nutrient intake and growth performance of older infants fed human milk.

STUDY OBJECTIVE: To determine whether the ad libitum addition of solid foods to the diet of exclusively human milk-fed infants will increase energy intake and reverse the decline in weight-for-age percentiles observed during the exclusive breast-feeding period. DESIGN: Weekly or biweekly measures of growth were made longitudinally on a cohort of infants from birth to 36 weeks of age, and monthly measures of nutrient intake were made from 16 weeks of age until 10 weeks after solid foods were introduced into the diet. SUBJECTS: Volunteer mother-infant pairs from middle and upper income groups who met entry criteria, including the intention to breast-feed exclusively for at least for 16 weeks; 58 pairs entered and 45 pairs completed the study. INTERVENTION: Solid foods were introduced at a time determined by the mother and the pediatrician; solid foods from controlled lot numbers were provided for each infant. MEASUREMENTS AND MAIN RESULTS: After solid foods were added, daily human milk intake declined at a rate of 77 gm/mo (p less than 0.001). Milk composition did not change during the observation period. Daily total energy intake increased 29 kcal/mo, but no changes were noted in energy intake when consumption was normalized for body weight. Weight (National Center for Health Statistics percentiles) at 28 weeks was 13 percentiles lower than that at birth, and length at 28 weeks was 1 percentile lower than at week 1. Weight and length percentiles at 28 weeks, when compared with peak values at 8 weeks, had dropped 19 and 14 percentiles, respectively. CONCLUSIONS: Energy intake of human milk-fed infants did not increase after solid foods were added to their diet but was maintained at approximately 20% below recommended levels. Energy intake appeared to reflect infant demands. These data suggest that the recommendations for the energy requirements of infancy should be reevaluated. The growth pattern of exclusively breast-fed infants differs from that of the National Center for Health Statistics reference population. These observations raise questions about the adaptive response of human milk-fed infants to different levels of energy intake and about the estimations of energy requirements based on the sum of basal metabolism, activity, growth, and diet-induced thermogenesis.

Body Weight↗

PubMed1986

Sources of variance in milk and caloric intakes in breast-fed infants: implications for lactation study design and interpretation.

Between-individual variation (BIV) and day-to-day variation (DDV) of total caloric and human milk intakes were examined in 17 infants. Nine were studied at months 5 and 6; 8 at months 6 and 7. All 17 were exclusively breast-fed for 5 full mo after which solid foods were added to the diet. Each infant was studied for five consecutive 24-h periods during which serial measurements were made of milk intake (test weighing) and solid food intake (pre- and postfeeding jar weighing). Total daily caloric intakes (kcal/day) were (mean +/- SD) 492 +/- 57, 547 +/- 70, and 567 +/- 98 at months 5, 6, and 7, respectively. Estimates of caloric intakes (kcal/kg/day) adjusted for body weight were 65.9 +/- 6.7, 72.6 +/- 11.2, and 70.9 +/- 13.0 at months 5, 6, and 7, respectively. Milk intakes (g/day) were 735 +/- 85, 640 +/- 106, and 562 +/- 214 at months 5, 6, and 7, respectively. BIV of milk intake increased after the introduction of solid foods. DDV (expressed as coefficient of variation) of caloric intake was nearly constant at each monthly observation and BIV increased from 8.8 at month 5 to 14.6 at month 7. The numbers of 24-h periods and subjects required for estimates of known precision of caloric and milk intakes of older breast-fed infants can be determined from these estimates of variance.

Adult↗

PubMed1985

Comparison of hand- and electric-operated breast pumps.

Volume, fat and energy contents were measured in human milk samples collected over 2 24-h periods with either an electric or hand-operated breast pump. The energy content was significantly higher and the variance for this measurement was significantly lower in samples obtained by the electric pump. The type of pump used is an important consideration when the content of energy and other nutrients associated with the fat compartment in human milk is to be evaluated. This observation is especially pertinent to cross-study comparisons, eg studies of well- and malnourished populations.

Adult↗

PubMed1984

Effect of maternal diet and body composition on lactational performance.

Milk production, dietary intake, and body composition of 45 lactating women were monitored for 4 months postpartum to examine the interrelationships of these maternal variables. A 3-day dietary record, 24-h test-weighing for determination of milk production, 24-h milk collection, anthropometric measurements, and water displacement for estimation of body fat were performed monthly. The overall mean (SD) energy intake was 2186 (463) kcal/day. Milk production (g/day) averaged 751 (130), 725 (131), 723 (114), and 740 (128) during the 4 sequential months. Weight postpartum was 64.6 (9.1) kg and was 59.3 (10.5) kg at 4 months. Body fat determined by water displacement averaged 28 (7)% at 1 month and 26 (8)% at 4 months. Estimations of body fat from skinfold thickness ranged from 28 (5)% postpartum to 27 (5)% at 4 months. Energy balance calculations based on the energy available from the diet plus the energy derived from tissue mobilization, minus the caloric equivalent of the milk, indicated sufficient energy available for maintenance and activity needs. Thus, it appears that successful lactation is compatible with gradual weight reduction and attainable with energy intakes less than current recommendations.

Adolescent↗

PubMed1983

A comparison of dietary methods in nutritional studies.

Dietary intakes of 40 lactating women were measured by a 7-day record (7DR) and compared with results using a 1-day record (1DR), 3-day record (3DR), and a newly developed food frequency form. The estimated intakes of energy, protein, calcium, phosphorus, and iron were used in the comparison. The subjects ranged from 3 wk to 6 months postpartum and all were totally breast-feeding their infants at the time of the study. The 7DR was recorded by the subjects and random days were chosen to provide 1DR and 3DR. The food frequency form is a method developed to estimate nutrient intakes based on the consumption of 105 food items. Intraclass correlation coefficients used to compare methods indicated good, moderate, and poor agreement for 3DR/7DR, 1DR/7DR, and food frequency form/7DR comparisons, respectively. Regression analysis was used to assess further the agreement between 3DR and 7DR. This analysis indicated that the 3DR cannot provide good individual estimates of nutrient intakes, but can provide a reasonable estimate of the general quality of the diet. Intakes also were classified as high (greater than 1 1/3 Recommended Daily Allowance), medium (2/3 to 1 1/3 Recommended Daily Allowance), or low (less than 2/3 Recommended Daily Allowance), and Cohen's kappa was used to measure agreement between methods. None of the intakes was found to agree with the 7DR classification. Intraindividual variation was found to be greater than interindividual variation.

Diet Surveys↗