26. PROTEIN METABOLISM IN VERY-LOW-BIRTH-WEIGHT (VLBW) INFANTS SMALL FOR GESTATIONAL AGE (SGA) FED PROTEIN FORTIFIED HUMAN MILK (HM)

Abstract

In order to demonstrate metabolic differences in response to protein intake we have studied 23 AGA and 19 SGA infants of VLBW at the eight day of life. The infants received HM or HM fortified with HM-lyophilisate at protein intakes ranging from 2.0 to 3.5 g/kg/d as calculated from protein content of the milk and the volumes ingested. α-amino-nitrogen and amino acids in serum as well as total nitrogen and α-amino-nitrogen excretion in the urine was measured. Serum α-amino-nitrogen and amino acid concentrations correlated with protein intake in both groups of infants, but concentrations were significantly higher in the SGA-infants above a protein intake of 2.5 g/kg/d. α-amino-nitrogen and total nitrogen excretions in the urine reflected also protein intake and were significantly increased in the SGA-infants. On the eight day of life a protein intake above 2.5 g/kg/d produces metabolic indices of protein overload in SGA-infants. These findings demonstrate that differences in protein metabolism are present between AGA and SGA infants of VLBW. A decreased rate of protein utilization for some time after birth may be present in the SGA-infants. When the nutritional management of VLBW-infants is planned these differences must be considered and protein intakes should be increased with caution in the SGA-infants.