Rice bran polysaccharide ameliorates ovalbumin-induced allergy and improves gut microbiota composition

This study is the first investigation of the effects of polysaccharide extracted from rice bran (RBP) on ovalbumin (OVA)-induced allergy and the gut microbiota, which hasn’t been reported previously. RBP in the medium-dose was found to significantly reduce the symptoms of food allergy (FA) in mice, lower the levels of histamine and allergen-specific (immunoglobulin E), and attenuate intestinal inflammation. Further studies demonstrated that RBP decreased allergy-associated responses in intestinal epithelial cells and Th2 cells while regulating Th1/Th2 differentiation to reach a dynamic equilibrium and downregulating Th2 polarization caused by allergies. Short-chain fatty acids (SCFAs) content and 16S rRNA sequencing revealed that RBP enhanced the abundance and diversity of the gut microflora and raised the content of SCFAs. These results suggest that RBP may mitigate FA by modulating the gut microbiota. This study revealed the effective use of rice bran and served as a basis for the development of innovative functional foods with anti-allergic properties.