Energy expenditure in human milk- versus formula-fed preterm infants

objective We compared energy expenditure (EE) of preterm infants fed their mother's milk versus preterm infant formula. Study design A prospective, randomized crossover,study of 13 healthy, appropriate weight for gestational age, gavage-fed, preterm infants. Before the study and according to our feeding protocol, infants uniformly received alternate feeds of human milk and formula. Each infant-was randomly assigned to 24 hours of formula feeding followed by 24 hours of breast milk or the reverse. Infants were studied asleep, at the end of each 24-hour period. EE was measured by indirect calorimetry 1 hour before feeding, 20 minutes during feeding, and 1 hour after feeding in a servo-controlled convective incubator. Energy,content of human milk was analyzed by bomb calorimetry. Results EE was significantly lower in breast milk-fed infants during prefeeding (52 +/- 6 vs 57 +/- 10 kcal/kg per 24 hours) (P < .05), per feeding (55 +/- 6 vs 60 +/- 10 kcal/kg per 24 hours) (P < .05), and at the postfeeding measurement (60 7 vs 65 7 kcal/kg per 24 hours) (P = .059). After correction of the results for the actual measured energy intake, an statistical differences reached the < .05 level. Conclusions Preterm infants have lower EE when they are fed breast milk than when they are fed preterm infant formula.