Protein intake during weaning. II. Metabolic responses.

Metabolic responses to different feeding regimens during the weaning period have not previously been studied. In this study 30 healthy infants aged 4-6 months were divided into three feeding regimens with 10 infants in each. The regimens were: Human milk (HM-group), formula F1 with 1.9 g protein/100 ml (F1-group) or formula F2 with 2.7 g protein/100 ml (F2-group). All infants received the same supplementary food and were fed ad libitum. Concentrations of serum urea were significantly higher (p less than 0.001) in the formula groups as compared to the breast-fed infants throughout the entire study period. Serum albumin concentrations were within normal limits in the breast-fed infants indicating adequate protein nutritional status. There were no differences in the concentrations of creatinine and total nitrogen in urine between the artificially fed and the breast-fed infants at the beginning of the study (4 months), but at 6 months these concentrations were significantly higher in the formula-fed (infants (p less than 0.001). The results suggest that formulas now in common use during weaning provide amounts of protein which produce metabolic manifestations implying excessive protein intakes.