2'-Fucosyllactose (2'-FL) is a fucosylated neutral trisaccharide composed of three sugar units: L-fucose, D-galactose, and D-glucose. It is the most abundant human milk oligosaccharide (HMO) found in human breast milk, accounting for approximately 30% of all HMOs. Its structure consists of an L-fucose residue linked in an α-1,2 configuration to a lactose molecule, which itself comprises galactose linked β-1,4 to glucose. First identified in the 1950s, 2'-FL has since been extensively studied due to its significant biological functions.

Chemically, 2'-FL has the molecular formula C₁₈H₃₂O₁₅ and a molecular weight of approximately 488.44 g/mol. It is resistant to digestion in the upper gastrointestinal tract, allowing it to reach the colon intact, where it acts as a prebiotic. By selectively promoting beneficial bacterial species such as Bifidobacterium, 2'-FL contributes to gut health and supports immune system modulation in infants.

Biological and Physiological Roles of 2'-FL

• Prebiotic activity: Selectively stimulates the growth of beneficial Bifidobacterium species, supporting a healthy gut microbiota.
• Antibacterial and antiviral effects: Helps prevent infections by blocking pathogen adhesion to the intestinal mucosa.
• Immunomodulation: Plays a role in the maturation and proper functioning of the infant immune system.
• Digestive resistance: Reaches the colon undigested, enabling its targeted biological activity.

Due to its documented health benefits, 2'-FL is now produced industrially through microbial fermentation and enzymatic synthesis for incorporation into infant formula and dietary supplements. It has been classified as Generally Recognized as Safe (GRAS) for human consumption.

In summary, 2'-Fucosyllactose is a key human milk oligosaccharide with well-established chemical, nutritional, and biological properties. It plays a critical role in infant health, particularly in gut microbiota development and immune protection. Its expanding applications in nutrition and biotechnology continue to represent a promising area of research and product innovation.