In recent years, manufactured HMOs have been introduced to the market, and multiple clinical trials have been conducted to evaluate their effectiveness. The first HMO to enter the arena, and most studied, is 2’Fucosyllactose (2’-FL), which is the most abundant HMO in human milk. Studies conducted with 2’-FL alone or with other HMOs showed that it is: safe and well-tolerated, supports healthy age-appropriate growth, and helps shift the gut microbiota toward the composition of breastfed infants. Supplementation with 2’-FL and other HMOs also improved stool consistency and supports immune function. ​

The way in which 2’-FL and other HMOs may exert their benefits has been researched, and it is suggested that the HMO-associated benefits are attributed to both the milk oligosaccharides and the metabolites produced during their fermentation by the gut microbiota. Since they are undigested by the gastrointestinal enzymes, they function primarily as prebiotics, modulating the colonization and composition of the intestinal microbiota.⁵

Furthermore, they serve as decoy receptors and prevent the adhesion of pathogens, thus being anti-microbial.¹ HMOs affect innate immune function by impacting the growth and differentiation of the intestinal epithelium immune response as well as intestinal barrier integrity.⁶ HMOs can also directly influence immune response through modulation of immune cell populations and cytokine production.⁷ Emerging data suggest that some HMOs might affect structural brain development and cognitive abilities by impacting the formation of synapses between neurons in the nervous system, as well as neuronal transmission.⁸​