Dietary GOS supplementation mitigates peanut-induced allergic responses through the gut microbiota–SCFA–barrier axis

Galacto-oligosaccharides (GOS) are common prebiotics, and further research is necessary to determine whether they exert positive effects on peanut allergy and to elucidate the underlying mechanisms. In our study, mice received GOS at doses corresponding to 0.5%, 2%, and 5% of the human-equivalent dose. The objective was to clarify the impact of GOS on intestinal barrier function, immune regulation, and microbial composition. Results demonstrated that medium and high doses of GOS significantly alleviated allergic symptoms and physiological indicators. This was achieved by restoring Th1/Th2 balance through suppression of Th2 cytokines (IL-4, IL-13) and promotion of IFN-γ production, while also enhancing intestinal barrier function via increased secretion of sIgA and tight junction proteins (ZO-1, Occludin). Gut microbiota analysis revealed that GOS increased microbial diversity and modulated community structure at both the phylum and genus levels. Notably, GOS enriched butyrate-producing bacteria, such as Coprococcus and Ruminococcus, which correlated with a significant increase in short-chain fatty acids, particularly butyrate and acetate. These findings suggest that GOS may alleviate peanut allergy by remodeling the gut microbiota, promoting the growth of butyrate-producing genera, and increasing the production of immunomodulatory metabolites, thereby improving intestinal barrier integrity and immune regulation.