Human milk protein supplementation for the prevention of hypoproteinemia without metabolic imbalance in breast milk-fed, very low-birth-weight infants.

In a group of 18 infants with birth weights of 1,500 gm or less, either preterm transitional or mature human milk was given during the time of initial hospitalization. Half of the infants were given protein supplement isolated from mature human milk which increased the protein content of the ingested milk by 0.8 gm/dl. The protein intake of these infants was increased by 0.6 to 1.6 gm/kg/day between two and 12 weeks after birth. The infants in the unsupplemented group developed hypoproteinemia at 8 to 12 weeks of age whereas those who received protein supplementation did not. We conclude that the hypoproteinemia resulted from nutritional lack of protein and did not represent a physiologic phenomenon of preterm development. There was no difference in the growth of the two groups. There was no evidence of any imbalance in amino acid metabolism even though there were significant correlations between individual protein intakes and plasma concentrations of tyrosine and phenylalanine. Protein intake of more than 3 gm/kg/day resulted in a mean serum urea nitrogen concentration of more than 15 mg/dl at 2 weeks of age, indicating that excessive protein intake should be avoided soon after birth.