Optimal growth and lower fat mass in preterm infants fed a protein-enriched postdischarge formula

Postdischarge formulas with extra energy and protein improve short-term growth but may also influence long-term body composition in an unwanted manner. Energy- and protein-enriched formulas with an increased protein-to-energy ratio improves gain of lean mass. The objective of the study was to investigate whether feeding a nutrient-enriched formula without extra energy after term, usually 3 to 4 weeks after discharge, would influence growth and body composition in infancy.

In this randomized controlled trial preterm infants were fed fortified human milk or preterm formula until term. At term, 102 infants were randomized to a nutrient-enriched formula without extra energy or standard formula until 6 months corrected age. Twenty-six infants received unfortified human milk after term. At term and 6 months corrected age, anthropometry and a dual-energy x-ray absorptiometry (DEXA) scan were performed. Lean and fat mass (FM) were corrected for height.

There were no differences in growth or body size between the feeding groups. Infants fed the enriched formula gained less FM and had lower FM corrected for body size at 6 months corrected age than infants fed standard formula. Infants fed human milk had lower lean mass and higher FM corrected for body size at 6 months corrected age than formula-fed infants.

Feeding nutrient-enriched formula without extra energy after term does not change quantity of growth but does influence type of weight gain and body composition of preterm infants. Infants fed the nutrient-enriched formula had lower FM corrected for body size at 6 months corrected age than infants fed standard formula or human milk.