Feeding preterm infants after hospital discharge: Effect of diet on body composition

Our purpose in this study was to examine whole body composition, using dual energy x-ray absorptiometry (DEXA) during dietary intervention in preterm infants (less than or equal to 1750 g birthweight, less than or equal to 34 wk gestation). At discharge, infants were randomized to be fed either a pr eterm infant formula (discharge-6 mo; group A) or a term formula (discharge -6 mo; group B), or the preterm formula (discharge-term) and the term formu la (term-6 mo; group C). Nutrient intake was measured between each clinic v isit. To measure: body composition, DEXA was used at discharge, term, 12 wk , 6 mo, and 12 mo corrected age. The data were analyzed by ANOVA. At discha rge, no differences were noted in patient characteristics between groups A, B, and C. Although energy intakes were similar, protein and mineral intake s differed between groups (A > C > B; p < 0.0001). During the study, weight gain and LM gain were greater in group A than B. At 12 mo, weight, LM, FM, and BMM but not % FM or BMD were greater in group A than B. However, the e ffects of diet were confined to boys, with no lasting effects seen in girls . In summary, therefore, DEXA was precise enough to detect differences in w hole body composition during dietary intervention. Increased weight gain pr imarily reflected an increase in LM and is consistent with the idea that th e preterm formula more closely met protein and/or protein-energy needs in r apidly growing preterm male infants.