Human Milk Oligosaccharides: the Link between Mother’s and Baby’s Health

Editor(s): Lars Bode.

A recent article by Prof. Lars Bode from the Larsson-Rosenquist Foundation Mother-Milk-Infant Center of Research Excellence, University of California, San Diego highlighted that human milk oligosaccharides (HMOs) may act as a connecting link between mother’s and baby’s health. The composition of HMOs in breast milk is influenced by various maternal factors such as genetics, stage of lactation and number of previous pregnancies, as well as environmental factors. These in turn can confer structure-specific direct and indirect benefits to babies.

HMOs are structurally diverse and complex oligosaccharides that are abundantly found in breast milk. They are not completely digested as they are resistant to low pH and intestinal enzymes and are found in traces in the urine and faeces of breastfed babies. However, a small part of HMOs is absorbed, which reaches the babies’ systemic circulation.

Prof. Bode underlined that most of the HMOs which are not absorbed, reach the colon, where they are utilised by the gut microbiota and promote the growth of beneficial bacteria. This effect of HMOs seems to be dependent on their structure.

HMOs are not just “food for bugs”. They also have bacteriostatic, bactericidal, antiadhesive and antimicrobial properties, thus protecting babies from various infectious agents. Moreover, HMOs can indirectly affect the gut microbiota by modulating epithelial and immune cell responses or can directly modulate the immune system.

Breastfed babies have a reduced risk of developing necrotising enterocolitis (NEC). Preclinical studies suggest that HMOs may also have a protective effect against NEC. Similar findings have been seen in a cohort study conducted among very low-birth weight infants. In addition, human intervention studies are needed to better understand the role of HMOs in protecting against NEC.

Likewise, the approach of combining preclinical and human cohort studies to define clinical intervention studies is currently being applied to other diseases in babies, such as diarrhoea, obesity, allergy and asthma. Additional studies are required to define how HMOs and lactation can influence the health of mothers.