Milk protein quantity and quality in the term infant. I. Metabolic responses and effects on growth

The growth and metabolic response of healthy, term infants during the first 12 weeks of life to feeding one of two formulas or human milk have been measured. Two groups of infants were fed ad libitum a 1.5 gm/100 ml bovine protein formula made up of either 60% whey and 40% casein proteins or 18% whey and 82% casein proteins. A third group of infants was breast-fed ad libitum. No consistent significant differences were observed among the groups with respect to rate of gain in weight, crown-rump length, crown-heel length, or head circumference. Blood urea concentration was significantly higher, and there was evidence suggesting compensation for an increased acid load from the second to the fourth weeks in both of the formula-fed groups compared with the breast-fed group. Blood cholesterol was significantly lower in both the formula-fed groups compared with the breast-fed group (P less than .001) and lower in the group fed the casein-predominant formula than it was in those fed the whey-predominant formula (P less than .05).