Researchers discover a compound in breast milk which fights harmful bacteria

New research has uncovered a compound in breast milk which could help protect babies from infections.

A new US study has identified a compound in human breast milk which can fight infections caused by harmful bacteria -- and which is not found in infant formula.

Carried out by researchers at National Jewish Health and the University of Iowa, the new study set out to investigate the antimicrobial and anti-inflammatory properties of the compound glycerol monolaurate (GML) in human milk compared to cow's milk and infant formula.

The researchers found that human breast milk has more than 200 times the amount of GML than that found in cows' milk, while infant formula has no GML at all.

The findings, published in the journal Scientific Reports, also showed that human breast milk is more antimicrobial than cow's milk or formula and inhibits the growth of pathogenic bacteria Staphylococcus aureus, Bacillus subtilis and Clostridium perfringens, while neither cow's milk nor infant formula had any effect at all. In addition, human breast milk did not inhibit the growth of Enterococcus faecalis, a beneficial bacteria.

The researchers also found that when they removed the GML from human breast milk, it lost its antimicrobial activity, and when GML was restored to the breast milk, it became antimicrobial once again. Cow's milk also became antimicrobial when GML was added to it.

The researchers also showed that GML inhibits inflammation in epithelial cells, which are the cells which line the gut and other surfaces; this is an important finding as inflammation can damage epithelial cells and increase the risk of bacterial and viral infections.

"Our findings demonstrate that high levels of GML are unique to human breast milk and strongly inhibit growth of pathogenic bacteria," said Donald Leung, MD, PhD, senior author on the paper.

'While antibiotics can fight bacterial infections in infants, they kill the beneficial bacteria along with the pathogenic ones," said Patrick Schlievert, PhD, first author on the paper. "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 cow's milk and infant formula that could promote the health of babies around the world."

The researchers note that GML is inexpensive to manufacture, and Drs. Schlievert and Leung have now applied for a patent for the use of GML as a beneficial additive to cow's milk and infant formula.