Glycerol monolaurate: Breast milk compound could be added to formula to boost beneficial bacteria

14 Oct 2019 --- Researchers have identified a compound in human breast milk that could be easily added to formula or cows’ milk to inhibit the growth of pathogenic bacteria. Glycerol monolaurate (GML) fights infections by harmful bacteria while allowing beneficial bacteria to thrive. The compound is inexpensive to manufacture but currently is not present in infant formula at all. Future research is now planned to ascertain whether GML would be a beneficial additive to cows’ milk and infant formula. The researchers have also applied for a patent for the use of GML in this way.

“Clinical studies are needed to demonstrate the benefit of using GML before formula manufacturers will adopt this approach. However, anyone who has illness due to Staphylococcus aureus infections could benefit from the use of GML. This could be in milk, used directly to the skin or as an oral intake in purified form,” Donald Leung, Professor of Pediatrics at National Jewish Health and an author of the paper, tells NutritionInsights. He expects that it will take five years to locate the funds for future research and perform clinical studies. 

The researchers determined that human breast milk contains over 200 times the GML levels of cows’ milk. They also found that unlike infant formula or cows’ milk, human breast milk inhibits the growth of Staphylococcus aureus, Bacillus subtilis and Clostridium perfringens. Crucially, human breast milk also did not inhibit the growth of the beneficial bacteria Enterococcus faecilis. Additionally, babies fed on human breast milk have high levels of beneficial Bifidobacteria, Lactobacilli and Enterococci.

“While antibiotics can fight bacterial infections in infants, they kill the beneficial bacteria along with the pathogenic ones,” says Patrick Schlievert, Professor of Microbiology and Immunology at the University of Iowa Carver College of Medicine and first author on the Scientific Reports 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 cows’ milk and infant formula that could promote the health of babies around the world.”

Human breast milk slowed the growth of pathogenic bacteria more than cows' milk or formula. (Source: Scientific Reports)The researchers also found that human breast milk lost its antimicrobial activity against S. aureus when GML was removed. Meanwhile, cows’ milk became antimicrobial when GML was added. GML also inhibits inflammation in epithelial cells, which line the gut and other mucosal surfaces. Inflammation can damage epithelial cells and contribute to susceptibility to both bacterial and viral infections.

Infant formula 
According to Innova Market Insights, the global baby formula market is expected to reach US$79 billion in 2020. Brands are especially keen to tout their products as being high in protein, with a 62 percent increase in the launch activity of baby formula products with a protein claim (Europe, CAGR 2014-2018). However, the average amount of protein in formulas is significantly higher than human breast milk, meaning reformulation may be necessary. 

A resemblance to mothers’ milk is key, with there being a 12 percent growth of formula claiming to mimic human breast milk (CAGR 2014-2018). One element of this is replicating human milk oligosaccharides (HMOs), of which over 200 species have been identified. They are a type of prebiotic that aids the growth of beneficial bacteria and protects against harmful varieties in the gut. HMO blends will continue to be developed for health purposes, while new technologies are set to make HMO production more affordable. 

Last week, a DuPont study uncovered some of the prebiotic mechanisms behind its product Care4U 2’-Fucosyllactose (2’-FL). The study found that it beneficially changes microbiota composition and the production of microbial metabolites compared to galacto-oligosaccharides (GOS) and lactose. 

Last month, a study pinpointed the key proteins that deliver HMOs to nourish important Bifidobacterium, contributing to a healthy infant gut microbiota. Additionally, 14 varieties of oligosaccharides naturally occur in goat milk baby formula, according to Australian research. HMOs have also been identified in amniotic fluid, meaning that fetuses are exposed to the compounds in utero. 

By Katherine Durrell