Feeding the low-birth-weight infant: I. Taurine and cholesterol supplementation of formula does not affect growth and metabolism

Taurine and cholesterol are constituents of human milk that are present in smaller amounts in infant formulas. Infants fed such formulas have lower plasma and urine concentrations of taurine and of serum total cholesterol. In the present investigation, in infants of 31 to 36 weeks gestational age, the effect of supplementing a 1.5 g/100 mL whey-predominant formula with taurine alone or with taurine plus cholesterol were examined. Infants fed the supplemented formula were compared with infants fed the unsupplemented formula and with infants fed pooled, expressed human milk (185 mL/kg/d). Approximately 45% of the human milk provided to each infant was that of the infant's mother (35% pasteurized and 10% fresh). From the time of reaching a weight of 2,400 g to 4 months of age the last group of infants was fed ad libitum. No consistent statistically significant differences in growth, as measured by rate of gain in crown-rump length, crown-heel length, or head circumference, were observed. There was a tendency, however, for the formula-fed infants to gain weight more slowly before reaching 2,400 g and to gain weight more quickly after a weight of 2,400 g was attained to 4 months of age. No differences in concentrations of BUN, total serum proteins, or acid-base status were observed among the formula-fed groups. The concentration of BUN increased in the formula-fed groups compared with the group fed human milk during the last half of the study. The formula-fed infants tended to have higher total serum proteins and to be slightly more acidotic than the infants fed human milk prior to discharge at a weight of 2,400 g but not thereafter. Thus, infants fed 185 mL/kg/d gained weight at rates comparable to those for fetuses of the same gestational age. Supplementation of formulas with taurine or taurine plus cholesterol did not produce changes in growth or general metabolism discernible under the present experimental conditions.