Human milk oligosaccharides (HMO) (HMO)

Human milk oligosaccharides (HMOs) are a complex group of unconjugated glycans that represent the third most abundant solid component in human breast milk, following lactose and lipids (Bode, 2012). Unlike lactose, HMOs are resistant to digestion in the upper gastrointestinal tract and reach the colon intact, where they serve as selective substrates for beneficial microbiota, most notably Bifidobacterium species (Walsh et al., 2020). These carbohydrates function through several distinct mechanisms: they act as prebiotics to shape the gut microbiome, serve as soluble decoy receptors that prevent pathogen adhesion to the intestinal epithelium, and directly modulate host immune responses (Triantis et al., 2018). Clinical interest in HMOs has grown significantly, with specific structures like 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT) being incorporated into infant formulas to mimic the protective effects of breastfeeding (Hegar et al., 2019). Research also explores their potential in treating adult conditions such as irritable bowel syndrome (IBS) and preventing necrotizing enterocolitis (NEC) in preterm infants (Plows et al., 2021). Their therapeutic utility is primarily focused on restoring healthy microbial ecology and enhancing innate mucosal immunity.

Other names

Human milk glycansBreast milk oligosaccharidesMaternal milk sugars

HMOs act as selective metabolic substrates for beneficial gut bacteria (prebiotic effect), function as soluble decoy receptors to prevent pathogen binding to host cells (anti-adhesive effect), and directly interact with immune cell receptors to modulate inflammatory responses.