Breast milk provides many benefits for babies. And now researchers say mother's milk contains an antibody that protects premature infants from an often-deadly intestinal bacterial disease called necrotizing enterocolitis (NEC).
Immunoglobulin A (IgA) antibodies protect against this disease. And preterm infants get IgA from their mother's breast milk during the first weeks of life, researchers from the University of Pittsburgh and UPMC Children's Hospital of Pittsburgh explained.
IgA antibodies bind to bacteria in the gut. The more bacteria that's bound with IgA, the less likely babies are to develop NEC, this study found.
"It's been well-known for a decade that babies who get NEC have particular bacteria – Enterobacteriaceae – in their guts, but what we found is that it's not how much Enterobacteriaceae there is, but whether it's bound to IgA that matters. And that's potentially actionable," said study senior author Timothy Hand. He's an assistant professor of paediatric infectious diseases at Pitt's School of Medicine.
The researchers analysed faecal samples from 30 preterm infants with NEC and 39 without NEC. Breast-fed babies had more IgA-bound gut bacteria – a good thing – than formula-fed babies. Infants who developed NEC were more likely to have been formula-fed.
Among babies without NEC, Enterobacteriaceae was largely tied up by IgA, allowing diverse types of bacteria to flourish. But among infants with NEC, IgA-unbound Enterobacteriaceae dominated in the days before the disease was diagnosed, according to the researchers.
The study was published in the journal Nature Medicine.
Benefits beyond IgA
As part of their research, the team bred mice that couldn't produce IgA in their breast milk. Pups that received IgA-free milk from their mothers were just as susceptible to NEC as those that were fed formula.
However, preventing NEC may not be as simple as adding IgA to infant formula, Hand said.
He noted that breast milk provides other benefits beyond IgA, so donor milk is the best choice if breastfeeding or pumped breast milk isn't an option.
"What we showed is that IgA is necessary but may not be sufficient to prevent NEC," Hand said in a university news release. "What we're arguing is that you might want to test the antibody content of donor milk and then target the most protective milk to the most at-risk infants."
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