Both infants and mothers can benefit from breastfeeding, according to the National Institute of Child Health and Human Development. While infants receive essential nutrients from mother’s milk, infants that are breastfed have better survival rates in their first year of life and are shielded from some infections. Skin-to-skin contact seems to provide emotional benefits as well. Preliminary research has also suggested that breastfed infants have lower rates of some diseases, including asthma, type 2 diabetes, and obesity, as well as potentially reducing the risk of allergies.
Now a team of scientists from National Jewish Health and the University of Iowa has found a molecule in breast milk called glycerol monolaurate (GML) that can allow good bacteria to thrive while fighting harmful microbes. There is 200 times more GML in human breast milk compared to cows' milk, and infant formula doesn’t contain any of it. The findings have been published in Scientific Reports.
"Our findings demonstrate that high levels of GML are unique to human breast milk and strongly inhibit [the] growth of pathogenic bacteria," said the senior author of the study Donald Leung, M.D., Ph.D., and a professor of pediatrics at National Jewish Health.
GML is not expensive to make, and might be an excellent addition to cows' milk and formula in the future; more work will be needed to confirm the findings.
"While antibiotics can fight bacterial infections in infants, they kill the beneficial bacteria along with the pathogenic ones," noted the first author of the study Patrick Schlievert, Ph.D., a professor of microbiology and immunology at the University of Iowa Carver College of Medicine. "GML is much more selective, fighting only the pathogenic bacteria while allowing beneficial species to thrive. We think GML holds great promise as a potential additive to cows' milk and infant formula that could promote the health of babies around the world."
In this study, the researchers demonstrated that human breast milk, but not formula or cows' milk, can disrupt the growth of microbial pathogens like Bacillus subtilis, Clostridium perfringens, and Staphylococcus aureus. The beneficial microbe Enterococcus faecilis was unaffected by the breast milk. Babies that consume breast milk carry high levels of good bacteria, including bifidobacteria, and lactobacilli.
Human breast milk was shown to have high GML levels, and when the researchers removed the molecule, the breast milk no longer exerted an antibacterial impact on S. aureus. Milk from cows gained an antimicrobial effect once GML was added to it, suggesting that GML is the molecule responsible for these impacts.
GML was also shown to reduce inflammation in cells that line the gut, epithelial cells. If those cells are damaged by inflammation, they can increase the risk of bacterial and viral infections.
The researchers are now interested in patenting the molecule.