Diet, fat accretion, and growth in premature infants

Metabolic studies were performed on 13 formula-fed, premature infants of very low birth weight (mean=1155 g) to compare growth and accretion of the 3 major nutrients (carbohydrate, protein, and fat) with that of the fetus of similar weight and gestational age. Anthropometric measurements, nutrient balance studies, and indirect calorimetry were used to analyze growth patterns and intake, use, and storage of energy and macronutrients. Data indicate that the infant exhibiting weight gains comparable to that of the third trimester fetus, retained energy at a level twice that of the fetus. Stored fat was the major component of the retained energy; infants deposited protein at a similar rate, but accumulated fat at a rate 3 times that of the fetus. Thus, the body composition of the formula-fed premature infant, and specifically the composition of weight gain, differ markedly from that of the placentally-nourished fetus. The consequences of body composition for subsequent growth and development of the premature infant are unknown. (nm)