PubMed Health⌕ Search

Biomedical subjects

S J Fomon

Publications and source records attributed to S J Fomon.

At least 55 records · Page 3Linked to original sources
PubMed1986

Requirement for sulfur-containing amino acids in infancy.

A series of studies designed to define the requirement of normal infants for sulfur-containing amino acids (methionine, cystine) was conducted with formulas providing 3.0, 2.8, 2.6, 2.2 or 1.8 g of isolated soy protein per 100 kcal. The formulas were fed with or without a methionine supplement. Adequacy of the diet was determined by measurement of growth, serum chemical indices and nitrogen balance. Nitrogen balance demonstrated a beneficial effect of methionine supplementation only at the lowest protein concentration (1.8 g/100 kcal). However, measurement of weight gain and/or serum concentrations of urea nitrogen and albumin clearly showed a beneficial effect of methionine supplementation at protein concentrations of 2.2 and 2.6 g/100 kcal. Intakes of sulfur-containing amino acids of 435 and 495 mumol/100 kcal therefore appear inadequate. At higher intakes of protein (2.8 and 3.0 g/100 kcal) there was no beneficial effect of methionine supplementation. Possible exceptions were male infants provided with 3.0 g protein per 100 kcal, in whom weight gain between 8 and 56 d of age was significantly (P less than 0.05) greater with than without a methionine supplement. Based on intakes of sulfur-containing amino acids from the formula providing 2.8 g of isolated soy protein per 100 kcal without methionine supplementation, we conclude that for male infants older than 56 d the requirement for sulfur-containing amino acids is no more than 588 mumol/100 kcal when intake of methionine is 264 mumol/100 kcal. However, it seems possible that such intake fails to meet the requirement in male infants less than 56 d of age. For female infants, regardless of age, 533 mumol/100 of sulfur-containing amino acids per 100 kcal meet the requirement when intake of methionine is 239 mumol/100 kcal.

Amino Acids, Sulfur↗
PubMed1986

Breast-feeding and evolution.

Several possibilities have been discussed as explanations for the failure of milk of the human species to meet certain nutritional needs of its young under living conditions prevailing in industrialized countries. The thoughts presented are speculative, and, in some instances, more than one explanation has been offered. The welfare of the mother as well as that of the infant must be considered--e.g., the mother's health might be seriously jeopardized if 0.5 to 1.0 mg of iron daily were secreted in milk. Moreover, evolutionary forces may be expected to influence milk production and composition in relation to diets and environmental conditions existing over several hundred thousand years. If we change our diets (e.g., consume less vitamin K) or if we change our environment (e.g., protect infants against sunlight and restrict the infant's contact with iron in dirt), milk that was adequate under prior living conditions may no longer be adequate. Finally, we wish to protect all infants against death or disability, including that resulting from a catastrophic event (e.g., intracranial bleeding as a result of vitamin K deficiency) too rare to be expected to influence evolutionary changes.

Biological Evolution↗
PubMed1985

Effect of dietary calcium on metabolic balance of normal infants.

Metabolic balance studies were performed with six normal infants fed in a balanced cross-over design three formulas differing only in calcium concentration: 389, 659, and 1024 mg/liter. Absorption of phosphorus was significantly affected by increasing calcium intake decreasing from 68 to 63 to 52% of intake. However, since urinary excretion of phosphorus also decreased, there was no significant effect on retention of phosphorus. Absorption of fat was slightly (but significantly) depressed by calcium, decreasing from 97.5 to 95.5 to 92.1% as calcium intake increased. The level of dietary calcium had no significant effect on absorption or retention of nitrogen, magnesium, copper, and zinc. One of the subjects had consistently lower absorption of calcium and fat than the other subjects, suggesting an absorptive defect. The decrease in fractional absorption of calcium (57 to 47 to 39% of intake) with increasing intake of calcium is compatible with adaptive regulation. On the other hand, the observation that absorbed calcium (mg/kg/day) was linearly related to intake of calcium with a slope of 0.373 suggests an alternative explanation: constant passive, concentration-dependent (slope), and constant active (y-intercept) transport of calcium over the range of calcium intakes. Thus, the findings are explainable in more than one way and do not necessarily demonstrate regulatory changes.

Calcium↗
PubMed1984

Respiratory and gastrointestinal illnesses in breast- and formula-fed infants.

Ten breast-fed infants, each paired with a formula-fed infant, were evaluated prospectively from birth to the age of 112 days to identify respiratory and gastrointestinal (GI) illnesses and microorganisms associated with respiratory tract infections. The infants were matched by age and sex. More GI illnesses occurred among the formula-fed infants. Although the breast-fed infants had less exposure to tobacco smoke in the home and less exposure to other children in day-care settings, there was no suggestion of a decrease in the frequency of respiratory illness during the first four months.

Bottle Feeding↗
PubMed1984

Indices of fatness and serum cholesterol at age eight years in relation to feeding and growth during early infancy.

During the early months of life, gains in length and weight are more rapid by formula-fed than by breast-fed infants and we and others have speculated that the greater gains of the formula-fed infants are the result of greater food intake. If overfeeding during early infancy resulted in establishment of habits of overeating, or if, for any other reason, diet-induced fatness in infancy persisted into childhood, we might be able to demonstrate differences in fatness in childhood related to mode of feeding (breast or bottle) during infancy. We therefore examined at age 8 years 469 children born in 1966-1971 who had been studied intensely in our unit from 8 to 112 days of age. At age 8 years there were no differences in indices of fatness related to mode of feeding during infancy. Serum concentrations of cholesterol at age 8 years were also of interest because of reports from animal studies that differences in feeding during early life may be responsible for subsequent differences in cholesterol homeostasis. Cholesterol concentrations at age 8 years did not demonstrate significant differences related to mode of feeding during infancy. It is possible, however, that age 8 years is too early for an effect to be demonstrated.

Adipose Tissue↗
PubMed1983

Sweetness of diet and food consumption by infants.

Normal female infants were studied from 8 to 112 days of age to determine the effect on food consumption of feeding formulas that differed widely in sweetness. One formula contained sucrose and the other a bland-tasting cornstarch hydrolysate. In a balanced, crossover design, it was found that food consumption was significantly greater during intervals in which the sweeter formula was fed.

Body Weight↗
PubMed1983

Formulas for premature infants: fate of the calcium and phosphorus.

Formulas designed for feeding of premature infants contain minerals added by the manufacturer. Although it is known that these minerals may be poorly suspended in the formula, little is known about concentrations of minerals in formula delivered to the infant under conditions prevailing in premature infant nurseries. In partially empty bottles of Similac Special Care, concentrations of calcium and phosphorus of this residual formula were found to be substantially greater than concentrations in full bottles. Presumably, concentrations of calcium and phosphorus in formula delivered to the infants was relatively low. Enfamil Premature and SMA Preemie infant formulas contain lesser quantities of added calcium and demonstrated less tendency to sedimentation. Substantial decrease in concentration of calcium was observed with all three formulas during continuous infusion, but the decrease was greatest with Similac Special Care. Little or no change in concentrations of calcium and phosphorus were observed with simulated bolus feeding by gavage.

Calcium, Dietary↗
PubMed1983

Dietary intake of lead and blood lead concentration in early infancy.

Under circumstances of low prenatal exposure to lead and low nondietary exposure to lead postnatally, four breast-fed infants and 25 formula-fed infants were studied to determine the relation between dietary intake of lead and blood lead concentration. From 8 through 111 days of age, the mean dietary intake of lead by the formula-fed infants was 17 micrograms/day (3 to 4 micrograms/kg/day), and intake of lead by the breast-fed infants was estimated to be only slightly greater. The mean blood lead concentration at the age of 112 days was 6.1 micrograms/dL. From 112 through 195 days of age, 17 infants continued in the study: ten received a mean dietary intake of lead of 16 micrograms/day, and seven received a mean intake of 61 micrograms/day. At 196 days of age, mean blood lead concentrations were significantly different (7.2 and 14.4 micrograms/dL, respectively).

Age Factors↗
PubMed1983

Lactose enhances mineral absorption in infancy.

To determine if lactose promotes the intestinal absorption of calcium and other minerals by infants, metabolic balance studies were performed with infants fed two formulas nearly identical in composition except for carbohydrate. One contained only lactose and the other contained sucrose and corn starch hydrolysate. Each of six normal infants had two balance studies performed with each formula in alternating sequence. When lactose was the carbohydrate, net absorption and net retention of calcium were significantly greater than when lactose was not present in the formula. Absorptions of magnesium and manganese were also significantly enhanced by lactose. Absorptions of copper and zinc were somewhat greater (not statistically significant) when lactose was present, whereas absorption of iron was not affected. Absorption of phosphorus was not different, but urinary excretion was less when the lactose containing formula was fed and, hence, net retention of phosphorus was significantly enhanced. These results confirm findings from animal studies and previous human studies and show that, in infants, lactose has a significant and sustained promoting effect on absorption of calcium and other minerals.

Calcium↗
PubMed1982

Immunologic consequences of feeding infants with cow milk and soy products.

Various products and regimens proposed for feeding infants when the mother's milk is not available have been evaluated intensively for capacity to achieve optimal nutrition. The immunologic consequences of feeding the foreign proteins contained in the various products have received much less attention and no systematic investigations have been done for comparable immunologic evaluation. Sera obtained at intervals from normal infants fed cow milk and soybean products from birth in different regimens were analyzed for antibodies to five major milk proteins and a soy protein isolate. Antibody levels increased slowly during the first 4 months, reaching a peak about 6 months of age. In infants fed cow milk products or a soy product from birth to 112 days of age and then given various cow milk products the following antibody responses were observed: The level of serum antibodies attained was highest with pasteurized cow milk and lower with heat-treated cow milk or a milk base formula of lower protein content. Feeding a soy product from birth for 112 days did not prevent a brisk antibody response to cow milk introduced subsequently, comparable to or greater than the antibody response seen when cow milk products were fed from birth. Clinically no immunologic disorders were detected in association with antibody responses to the various products and regimens. The implications of the findings for infant feeding and immunologic disorders are discussed.

Adolescent↗
PubMed1982

Methods in infant nutrition research: balance and growth studies.

Questions of infant nutrition can often be answered by metabolic balance studies or by studies of food intake and growth. The methods used by the authors for these approaches are described and an example of each is given. Balance studies demonstrated that lactose was more effective than a corn starch hydrolysate in promoting absorption of calcium, magnesium and manganese. A study of food intake and growth provided convincing evidence of the ability of infants to digest starch adequately after 6 weeks of age. There was a suggestion that some infants less than 6 weeks of age had limited ability to digest starch.

Calcium↗
PubMed1981

Cow milk feeding in infancy: gastrointestinal blood loss and iron nutritional status.

Eighty-one normal infants were studied between 112 and 196 days of age. Thirty-nine infants were fed pasteurized cow milk and the remainder were fed either Enfamil or heat-treated cow milk. During the age interval of 112 to 140 days, the proportion of infants with guaiac-positive stools was significantly (P less than 0.01) greater among infants fed pasteurized cow milk than among those fed Enfamil or heat-treated cow milk. Similarly, infants fed cow milk had a significantly (P less than 0.001) greater number of guaiac-positive stools than did the other infants. After 140 days of age, there was no difference between feeding groups in the number of guaiac-positive stools. No significant differences were observed in mean hemoglobin, hematocrit, serum iron, total iron-binding capacity, or transferrin saturation between feeding groups nor between infants with and those without guaiac-positive stools, It is concluded that pasteurized cow milk should not be fed before 140 days of age.

Animals↗
PubMed1981

Urination during the first three years of life.

Urination was studied in 15 normal infants and young children on 150 occasions in the course of metabolic balance studies. With increasing age, mean urine volume increased if expressed as ml/day and decreased if expressed as ml/kg/day. Urine volume was correlated with volume of intake (r = 0.697) and accounted for a similar percentage of volume of intake irrespective of age. The mean number of voidings decreased from 20.1 per day during the first month of life to 10.8 per day in the third year of life. Absolute voiding size increased with age but did not change per unit of body weight. This study establishes urine volume, voiding frequency and voiding size of normal children during the first 3 years of life.

Age Factors↗
PubMed1981

Body composition of a nine-year-old reference boy.

Utilizing available data and several assumptions, the body content of water, minerals, protein, carbohydrate, and fat has been estimated for a 9-year-old reference boy. This reference boy is leaner than the reference man (13.4 versus 15.3% of body weight) and his fat-free body mass exhibits greater concentration of water (75.5 versus 73.7%) and lesser concentrations of potassium (66.8 versus 68.1 mEq/kg) and total minerals (4.7 versus 6.9%). If age-specific values are used for composition of fat-free body mass body composition), it will be possible to avoid underestimation of fat content calculated from data on total body water and overestimation of fat content calculated from 40K counting data or from body density determined by underwater weighing.

Body Composition↗