There's an Antimicrobial Compound in Breast Milk

Breast milk is incredible. We really don’t need more studies to prove that breast milk has a ton of benefits for babies. We get it and we also get that breastfeeding isn’t an option for everyone. But researchers are now looking further into the properties of human milk to figure out just how it works its magic because understanding what makes breastmilk great can help parents who feed their babies breastmilk, formula or both.

One recent study has identified a compound responsible for killing off bad bacteria, and their work might eventually help those who can’t breastfeed their babies.

The study, published this month in the journal Scientific Reports, shows that human milk contains 3,000 micrograms per milliliter of a compound called glycerol monolaurate (GML). Cow’s milk contains only 150 micrograms per milliliter of the stuff, and infant formula has none. Researchers from National Jewish Health and the University of Iowa then tested human milk, cow’s milk and formula to see their effect on the growth of certain bacteria.

Compared to the other two milks, human milk was much better at stopping the growth of Staphylococcus aureus, Bacillus subtilis, Clostridium perfringens, and Escherichia coli—all of which can cause nasty infections and G.I. illnesses. (GML alone isn’t very effective against Escherichia coli, a.k.a. E. coli, but the scientists believe it works in conjunction with other compounds in breastmilk to kill that bacteria.)

When the scientists then removed GML from the breastmilk, it stopped battling the harmful bacteria. And when they added GML to cow’s milk, it successfully stopped the growth of Staphylococcus aureus. They also found that GML has anti-inflammatory properties, which is helpful in protecting babies’ intestines and may be why breast milk is an effective treatment for atopic dermatitis.

“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,” Patrick Schlievert, PhD, professor of microbiology and immunology at the University of Iowa and the paper’s first author, said in a press release.

So while GML is one more reason breastfeeding is awesome, this research is also getting us a step closer to helping the many children for whom that is not an option.