Supplementation of breastmilk with bovine formula not associated with differences in gut microbiome

1. There were no significant differences in morbidity or gut microbiota diversity, for preterm infants randomized to supplementing a mother’s own breast milk (MOM) with bovine formula versus donor human milk.

Evidence Rating Level: 1 (Excellent)

In preterm infants, consuming a mother’s own breast milk (MOM) has been associated with reductions in neonatal morbidity. However, when there is an insufficient amount of MOM supply, it is not entirely clear whether pasteurized donor human milk (DHM) versus bovine formula is the better choice. A meta-analysis did show lower rates of necrotizing enterocolitis (NEC) for DHM compared to formula, when these were the sole dietary options, but no difference when these were used to supplement low MOM supply. It is hypothesized that any potential differences in rates of NEC may be due to differences in gut microbiota from consuming DHM versus formula. Therefore, this randomized controlled trial aimed to assess differences in neonatal morbidity and gut microbiome diversity of preterm infants on a solely human milk diet compared to a diet with bovine formula. The study population consisted of infants born under 30 weeks of gestation, who did not receive milk apart from MOM in the first 3 days of life, and who did not have life-threatening comorbidities. The control consisted of infants feeding with MOM, and supplementing with formula, whereas the intervention consisted of infants feeding with MOM and supplementing with ready-to-feed pasteurized human milk. At 34 weeks, stool samples were collected and DNA sequenced to assess the gut microbiota. In total, there were 126 infants with 63 randomized to either group. The median (range) percentage of enteral intake from supplemental formula or ready-to-feed was 1% (0-100%) and 24% (0-99%) respectively. There were no significant differences in neonatal outcomes, such as time to full feeds, rates of NEC, weight gain, or length of stay. There were also no significant differences in bacterial richness or Shannon diversity, though there was decreased abundance of Lactobillus in the exclusive human milk group (p = 0.03). Overall, this study demonstrated no significant differences in neonatal morbidity outcomes or gut microbiome diversity when supplementing MOM with bovine formula compared to human milk.

Click to read the study in JAMA Network Open

Image: PD

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