PROTEIN AND ENERGY REQUIREMENTS OF LOW BIRTH WEIGHT (LBW) INFANTS

Abstract

Growth and metabolic response of LBW infants (BW, 900-1750g) assigned randomly at birth to formulas providing daily protein and calorie intakes of either 2.25g/kg and 120 kcal/kg(A;n=9), 3.8g/kg and 120 kcal/kg(B;n=9) or 3.8 g/kg and 160 kcal/kg (C;n= 9) were determined. Weight gain of infants fed A (23.8±3.Og/d) was less (p<0.05) than that of infants fed B (33.6±4.8g/d) or C (40.2±4.9g/d); that of C was greater than that of B (p<0.05). Increases in length and head circumference were not different among the 3 groups but triceps and subscapular skinfold thickness (ΔSFT) increased more rapidly in those fed G(p<0.05). Nitrogen retention of infants fed A(140±44mg/kg.d) was less (p<0.05) than infants fed B or C(293±88 and 283±38mg/kg.d). BUN (1.3±0.8 mg/dl, albumin (2.76±0.3g/dl) and prealbumin (6.2±1.9mg/dl) concentrations as well as the plasma concentration of most amino acids were also lower (p<0.05) in infants fed A. The lower weight gain and nitrogen retention of infants fed A along with the metabolic evidence of protein inadequacy suggests that a protein intake of 2.25g/kg.d is inadequate.