Galactooligosaccharide (GOS)

Galactooligosaccharide (GOS) is a non-digestible oligosaccharide composed of galactose monomers (typically 2-10 units) linked by β-(1→3), β-(1→4), or β-(1→6) glycosidic bonds, often with a terminal glucose, derived primarily from lactose. It resists hydrolysis by human digestive enzymes and reaches the colon intact, where it serves as a selective substrate for beneficial gut bacteria such as Bifidobacterium and Lactobacillus species, promoting their growth and metabolic activity through specific enzymatic degradation (e.g., via bacterial α- and β-galactosidases). This prebiotic effect fosters a healthy microbiota composition, enhances short-chain fatty acid production, and supports intestinal barrier function. GOS is commercially produced enzymatically from lactose and incorporated into functional foods like infant formula and yogurt to mimic human milk oligosaccharides. While not a molecular target like receptors or enzymes, its structural variations (e.g., degree of polymerization, linkage types) influence probiotic strain selectivity, enabling tailored synbiotic applications. No direct disease causation or drug interactions are established; benefits are nutritional rather than therapeutic.

Other names

α-Galactooligosaccharideβ-GalactooligosaccharideGalacto-oligosaccharidesRFO (raffinose family oligosaccharides)