Effects of human milk on body composition and growth in very low birthweight infants

Objective To compare body composition and growth in very low birthweight infants according to their source of human milk: maternal expressed breast milk (MEBM) versus donor breast milk (DBM). We hypothesized that infants fed predominately MEBM would exhibit reduced body fat percentage compared to those fed predominately DBM. Methods Premature infants weighing ≤1500 g on an exclusive human milk diet were enrolled in a single-center study between 2017 and 2021. Demographic data and anthropometric measurements were collected. All infants underwent body composition analysis via dual energy x-ray absorptiometry at 36 weeks corrected post menstrual age. Results A total of 60 infants were enrolled and 48 were included in the primary analysis. No differences were detected in percent body fat (14 vs. 12%, p = 0.7) or fat-free mass (2050 vs. 2130 g, p = 0.7). Both groups displayed similar growth and anthropometric measurements. Caloric and macronutrient intake between groups was similar. Conclusion In the cohort of patients studied, no differences were observed in percent body fat based on primary human milk type intake in the first 28 postnatal days. Further investigation is required in a larger population of exclusive human milk fed preterm infants to determine if body composition differences exist based on an infant’s primary human milk source. Impact Premature infants are at risk for altered body composition at term corrected age, specifically increased body fat percentage, which may have implications for the future. To our knowledge this is the first study exploring body composition outcomes based on an infant’s primary human milk source. Infants fed exclusive human milk (e.g., donor vs. maternal) displayed similar percent body fat and growth outcomes.