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Biomedical subjects

N F Butte

Publications and source records attributed to N F Butte.

At least 73 records · Page 4Linked to original sources
PubMed1991

Heart rates of breast-fed and formula-fed infants.

Heart rates of 46 breast-fed and formula-fed infants were monitored continuously for approximately 18 h at 1 or 4 months of age. Heart rate differed significantly by age (1 month greater than 4 months; p less than 0.001) and feeding mode (breast-fed less than formula-fed; p less than 0.001). Approximately 58% of the variability in heart rate could be attributed to feeding mode, sex, and age. Heart rate was correlated significantly with energy intake (r = 0.60; p less than 0.001), but not sleeping metabolic rate or total daily energy expenditure. Energy intake accounted for none of the variability in heart rate beyond that explained by feeding mode, sex, and age.

Age Factors↗
PubMed1990

Energy intakes of human milk-fed infants during the first year.

A discrepancy between current recommendations for energy intakes and the reported intakes of human milk-fed infants has led to the suggestion that energy requirements of infants should be reevaluated. Gross energy intakes of 1-month-old, exclusively breast-fed infants are similar to recommended amounts of metabolizable energy; however, by 4 months of age, gross energy intakes of exclusively breast-fed infants are significantly less than current recommendations. Weight-for-age percentiles also fall during that period. Energy intakes (measured in kilocalories per kilogram) persist at less than recommended amounts, and weight-for-age percentiles continue to drop after solid foods are added to the diet. Energy intakes of formula-fed infants appear significantly higher than those of infants who are fed human milk. Growth rates, total daily energy expenditure, sleeping metabolic rates, minimal rates of energy expenditure, rectal temperature, and heart rates have been found to be lower in breast-fed infants. The maintenance of energy intakes and growth trajectories during the period of demand supplementation with solid foods suggests that intakes, growth rates, and rates of energy expenditure of human milk-fed infants are physiologic responses to an appropriate dietary intake.

Body Weight↗
PubMed1990

Energy utilization of breast-fed and formula-fed infants.

Breast-fed and formula-fed infants (n = 65) were studied at 1 and 4 mo of age to elucidate differences in energy utilization between feeding groups. Gross energy intake at 1 mo was comparable between groups but was statistically different at 4 mo. Weight, length, and weight gain were not different between groups. Energy expenditure 0-4 h postprandially did not differ between feeding groups. Sleeping metabolic rates (SMRs) were not different but minimal observable energy expenditures standardized by weight were lower among 4-mo-old breast-fed infants (p less than 0.03). No differences were found between feeding groups in thermic effect of feeding (TEF). Activity patterns revealed that breast-fed infants slept less than formula-fed infants (p less than 0.04). Disparities in energy intake observed between breast-fed and formula-fed infants at 4 mo of age did not result in statistically significant differences in growth rate, SMR, or TEF.

Analysis of Variance↗
PubMed1990

Energy expenditure and deposition of breast-fed and formula-fed infants during early infancy.

The energy intake, expenditure, and deposition of 40 breast-fed and formula-fed infants were investigated at 1 and 4 mo of age to explore possible differences in energy utilization between feeding groups. Energy intake was calculated from 5-d test-weighing records or pre- and postweighing of formula bottles, in combination with bomb calorimetry of the milks. Total daily energy expenditure (TDEE) was determined by the doubly labeled water method. Sleeping metabolic rate (SMR) and minimal observable energy expenditure were measured by indirect calorimetry. Activity was estimated as the difference between TDEE and SMR. Energy deposition was estimated from dietary intake and TDEE. Energy intakes were significantly higher for the formula-fed than breast-fed infants at 1 mo (118 +/- 17 versus 101 +/- 16 kcal/kg/d) and 4 mo (87 +/- 11 versus 72 +/- 9 kcal/kg/d) (p less than 0.001). TDEE averaged 67 +/- 8 and 64 +/- 7 kcal/kg/d at 1 mo and 73 +/- 9 and 64 +/- 8 kcal/kg/d at 4 mo for the formula-fed and breast-fed infants, respectively, and differed between feeding groups (p less than 0.04). SMR and minimal observable energy expenditure (kcal/min) were higher among the formula-fed infants at 1 and 4 mo (p less than 0.005). The energy available for activity and the thermic effect of feeding did not differ between feeding groups. Rates of weight gain (g/d) and energy deposition (kcal/kg/d) tended to be greater among the formula-fed infants at 1 and 4 mo (p less than 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Basal Metabolism↗
PubMed1990

Comparison of energy expenditure estimated in healthy infants using the doubly labelled water and energy balance methods.

The doubly labelled water method was used to estimate energy expenditure in 20 formula-fed infants (10 aged 1 month and 10 aged 4 months). We then compared the energy expenditure values with energy balance values calculated from energy intake and energy cost of growth. Our purpose was to compare various published equations for calculating CO2 expiration rates (and thus energy expenditure values) from the isotopic data. Those equations in which we used measured values for 18O and 2H isotope dilution spaces and estimated or measured values for insensible water losses yielded energy expenditure values (69.7 +/- 8.4 kcal/kg/d) that agreed most closely with energy balance data (70.3 +/- 11.9 kcal/kg/d). Equations in which we used a constant ratio of 1.03 between the 2H and 18O isotope dilution spaces resulted in energy expenditure values (66.3 +/- 10.2 kcal/kg/d) lower than those predicted by the energy balance data. Data analysis by nonlinear curve fitting compared to logarithmic transformation did not alter the estimates of energy expenditure obtained in these infants.

Child Development↗
PubMed1989

Body composition of lactating women determined by anthropometry and deuterium dilution.

1. Body fat, fat-free mass and total body water of ten lactating women were estimated from deuterium-dilution spaces and from skinfold thickness measurements. Deuterium-dilution spaces were calculated from the 6 h (equilibration) and zero-time (extrapolation) deuterium enrichments in saliva, urine, human milk and breath water vapour samples. 2. The deuterium spaces obtained by equilibration were statistically larger than those obtained by extrapolation. Isotope dilution spaces derived from deuterium enrichments in saliva, breath water vapour and human milk did not differ with the exception of the 6 h equilibration value of milk, which was greater than that estimated from saliva. Deuterium-dilution spaces estimated from urine were consistently smaller than those derived from the other biological fluids. 3. No significant differences in body fat, fat-free mass and total body water were observed between anthropometric measurements and deuterium-dilution methods, except for extrapolated values derived from deuterium enrichments in urine.

Adult↗
PubMed1988

Human-milk intake measured by administration of deuterium oxide to the mother: a comparison with the test-weighing technique.

A comparison was made between the dose-to-the-mother deuterium-dilution method and the conventional test-weighing technique for determining human-milk intake in five exclusively breast-fed infants and in four breast-fed infants who received supplemental foods. After administration of 2H to the mothers human milk and infant urine were sampled over 14 d and analyzed for 2H:1H ratios by gas-isotope-ratio mass spectrometry. Infant total body water was determined by 18O dilution. The test-weighing procedure was conducted for 5 d consecutively. The intake of human milk (mean +/- SD) estimated by 2H dilution was 648 +/- 63 g/d and estimated by test-weighing was 636 +/- 84 g/d. The mean difference between the two methods was not significantly different from 0. The 2H-dilution and test-weighing techniques provide similar estimates of human-milk intake.

Adult↗
PubMed1988

Variability of macronutrient concentrations in human milk.

Variability observed in the energy, total nitrogen, lactose and fat concentrations of human milk was partitioned among subjects, days and sample duplicates. Highly significant differences were detected between individuals and between days within the individual for all four nutrients (P less than 0.001). Subjects, days and sample duplicate determinations contributed 89, 9 and 2 per cent, respectively, to the variance for energy; 87, 12 and 1 per cent for nitrogen; 75, 21 and 4 per cent for lactose; and 92, 8 and less than 1 per cent for fat. The reliability of mean estimates for a group or for an individual was derived for various combinations of subjects, days and duplicates to provide a tool for planning future studies.

Adult↗
PubMed1987

Macro- and trace-mineral intakes of exclusively breast-fed infants.

Intakes of calcium, phosphorus, magnesium, zinc, sodium, potassium, iron, and copper of 45 exclusively breast-fed infants were determined during the first 4 mo of life. Direct 24-h measurements of milk intake and mineral contents of human milk were used to estimate mineral intakes. Daily intakes of Ca, P, Zn, K, Na, Fe, and Cu decreased significantly over the study period while the intake of Mg increased. With the exception of Mg, mineral intakes on a weight basis displayed significant quadratic trends over the 4 mo. In spite of seemingly low-mineral intakes, growth progressed satisfactorily.

Body Height↗
PubMed1987

Special properties of human milk.

Human milk is a highly complex fluid with a nutrient balance and an array of functional properties that may promote a level of metabolic efficiency that is not attainable when a cow milk-based formula is fed. This is not a novel idea. Mitchell in 1933 proposed that the level of efficiency of energy use is determined by the nutrient "balance" in the diet. Nonetheless, difficulties remain in the attempt to reconcile the low levels of intake with established estimates of energy needs. If the amount of energy that appears necessary for growth and maintenance of a 4-month-old infant is compared with that from his or her intake of an exclusive human milk diet, the infant should have little or no energy left for activity. Do metabolic economies contribute to more efficient uses of energy for growth and maintenance in breastfed infants? Are there differences in body composition? Does more efficient use of energy occur as a result of a decrease in clinical and subclinical infections? Is efficient energy utilization accomplished by significant curtailment in activity? If an excess level of energy is consumed by bottlefed infants, what are the positive or negative short-term or long-term consequences? These questions are the focus of research in numerous laboratories. Field and clinical studies of breastfed infants and in vitro studies of human milk offer unique opportunities to understand basic mechanisms of human adaptations to nutrient intake and environmental challenges.

Adult↗
PubMed1985

Feeding patterns of exclusively breast-fed infants during the first four months of life.

Milk intake and feeding patterns of 45 exclusively breast-fed infants were documented longitudinally over the first four months of life. Two prevailing feeding patterns were identified: one in which feedings were distributed throughout the 24-h day and one in which feedings were excluded from the early 12:00 a.m. to 6:00 a.m. period. No significant differences in total milk intake (g/24 h) were detected the day irrespective of feeding pattern. Feeding frequency and duration declined in successive months of lactation. Total milk intake was not significantly correlated to feeding frequency or duration.

Adolescent↗
PubMed1985

Prediction of body density from skinfold measurements in lactating women.

Regression equations predicting body density from skinfold measurements were derived for a group of lactating women. It was concluded that specific equations for lactation were not necessary, since the resultant equations were not significantly different from those published for non-lactating women. The ability to predict an individual's body density from skinfold thickness measurements was unsatisfactory for either clinical or research applications.

Adipose Tissue↗
PubMed1984

Longitudinal changes in milk composition of mothers delivering preterm and term infants.

The concentrations of protein nitrogen (PN), non-protein nitrogen (NPN), energy, fat, sodium (Na), calcium (Ca), phosphorus (P), magnesium (Mg), and zinc (Zn) were determined in human milk from mothers giving birth to full-term (n = 13) and preterm infants (n = 8). Milk samples were collected under controlled conditions at two-week intervals for 12 weeks postpartum. Statistically significant differences in PN, Ca, and P concentrations were detected between the milk from mothers of preterm and term infants. The mean PN concentration in the preterm milk was statistically higher than that of term milk (198 vs. 164 mg N/dl), in contrast to the lower mean Ca (220 vs. 261 mg/l) and P (125 vs. 153 mg/l) concentrations detected in the preterm milk. No other differences in mean nutrient concentration were observed between the two groups. Concentrations of PN, NPN, Na, P, and Zn decreased over time. The concentration of Mg increased slightly. The content of fat, energy, and Ca did not change.

Adult↗
PubMed1984

Human milk intake and growth in exclusively breast-fed infants.

Milk intake and growth in 45 exclusively breast-fed infants were documented during the first 4 months of life. Energy and protein intakes were substantially less than current nutrient allowances. Energy intake declined significantly from 110 +/- 24 kcal/kg/day at 1 month to 71 +/- 17 kcal/kg/day at 4 months. Protein intake decreased from 1.6 +/- 0.3 gm/kg/day at 1 month to 0.9 +/- 0.2 gm/kg/day at 4 months. Infant growth progressed satisfactorily, compared with National Center for Health Statistics standards. A reevaluation of energy and protein intakes and allowances during infancy is merited.

Adolescent↗
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↗
PubMed1984

Daily ingestion of immunologic components in human milk during the first four months of life.

The amounts of lactoferrin, lysozyme, SIgA and SIgA antibodies to E. coli somatic antigens in human milk ingested per day and per kg per day by breast-fed infants were determined during the first four months of life. A gradual decline in the amounts of lactoferrin, SIgA, and SIgA antibodies ingested per day or per kg per day was found, whereas the quantities of lysozyme ingested by the infants rose during that period. These data suggest that the production and secretion of these immunologic factors by the mammary gland may be linked to the ontogeny of the production or catabolism of those components at mucosal tissues of the recipient infant.

Antibodies, Bacterial↗