2fucosyllactose

2'-Fucosyllactose, also written as 2fucosyllactose and abbreviated 2'-FL, is a fucosylated oligosaccharide that is one of the most abundant human milk oligosaccharides (HMOs) in human milk. Its structure is a fucose alpha-1,2 linked to the galactose unit of lactose, giving the composition Fuc(alpha1-2)Gal(beta1-4)Glc. The amount of 2'-FL in milk varies with maternal secretor status, which is determined by the FUT2 gene; secretor mothers produce higher levels, while non-secretors have little to none.

In nature, the primary source of 2'-FL is human milk, particularly in the early stages of lactation. It is also produced industrially by biotechnological processes, such as microbial fermentation or enzymatic synthesis, to supply infant formulas and some dietary supplements. These processes enable the production of 2'-FL with consistent quality for supplementation.

Functionally, 2'-FL serves as a prebiotic, promoting the growth of beneficial gut bacteria such as Bifidobacterium species. It also acts as a decoy receptor that can inhibit adhesion of certain pathogens to the intestinal mucosa, potentially reducing infections. Research suggests possible roles in immune development and gut barrier function, but findings are not yet conclusive and vary across studies.

Regulatory and safety considerations: when produced via approved biotechnological methods, 2'-FL is used as an ingredient in some infant formulas and is generally regarded as safe by major regulatory authorities in various regions.

See also: other HMOs such as 3-fucosyllactose and lacto-N-tetraose, and research on the infant gut microbiome.