Selenium-enriched tea polysaccharide treatment ameliorates walnut protein allergy by regulating gut microbiota and metabolism.

Selenium-enriched polysaccharides conventionally possess multiple benefits for human health. To investigate the anti-allergic ability of selenium-enriched tea polysaccharide (Se-TPS) and its effect on the gut microbiota and metabolism, a walnut protein (WP)-induced allergic BALB/c mouse model was established. In vivo, Se-TPS (250 mg kg-1) alleviated the clinical allergic symptoms of WP sensitization and repaired the intestinal barrier. Furthermore, Se-TPS can inhibit the over-secretion of IgE, HIS, and IL-4 and promote the normal secretion of TGF-β and IFN-γ to ameliorate the WP-induced immune imbalance. The gut microbiota was analyzed by 16s rRNA, which showed that Se-TPS upregulated the abundance of beneficial bacteria and effectively repaired the disturbed gut flora. Nontargeted metabolomics revealed that Se-TPS improved gut metabolic disorders by modulating tryptophan metabolism, primary bile acid metabolism, caffeine metabolism, steroid synthesis, ubiquinone biosynthesis, and other terpenoid-quinone biosynthesis. In summary, Se-TPS could mitigate WP-sensitive allergy by balancing Th1/Th2/Treg immune responses and modulating the gut microbiota and metabolites. This study confirmed that Se-TPS has the potential to regulate allergies and offers novel insights into functional foods utilizing Se-TPS.