By Chloe Autran, PhD
Mothers’ milk contains various amounts of unique sugars known as human milk oligosaccharides (HMOs). The concentration and variation of HMOs in each mother’s milk depend on several factors that include her lactation stage (colostrum, transitional milk, mature milk), her genetic predisposition, her geographic location, and possibly her diet. This diversity of HMOs present in human milk suggests that each baby requires his or her own individualized protection against pathogens such as harmful bacteria, viruses, and toxins.
When pathogens infect a baby, they usually invade by latching onto the molecules located on the surface of the intestinal cells. HMOs resemble these molecules, causing the pathogens to mistakenly stick to these sugars rather than the baby’s vulnerable intestinal cells. Since HMOs are not digested by the infant, the HMOs, along with the pathogen sticking to them are washed out into the baby’s diaper.
By acting as decoys to pathogens, HMOs help prevent possible infections or diseases and offer direct protection to babies.1
The structure of the various HMOs can block different pathogens that are known to cause bacterial diarrhea, such as Salmonella, Campylobacter jejuni, and even some pathogenic strains of E coli. 2 HMOs are also thought to prevent certain viruses, such as norovirus and rotavirus, from harming a baby.2
Since many infants of HIV-infected mothers who drink milk containing the virus don’t get infected, specific HMOs may somehow play a role in preventing HIV transfer from mother to baby.3 The natural protection provided by HMOs cannot be replaced with cow-milk derived formula’s which lack the amount and diversity of HMOs naturally found in breast milk.