A comparative study of human milk oligosaccharides: 6′-sialyllactose enhances gut barrier function and immune homeostasis to alleviate food allergy

, and significantly elevating the concentrations of acetate, butyrate, and valerate. 6'-SL exerts a unique protective effect against food allergy through integrated immunoregulatory and microbial mechanisms, notably by enhancing Treg activity and enriching SCFA-producing bacteria. These findings highlight the structure-dependent functionality of HMOs and position 6'-SL as a promising candidate for targeted dietary interventions against food allergy.