Protein diets with the role of immune and gut microbial regulation alleviate DSS‐induced chronic ulcerative colitis

The association between diet and inflammatory bowel disease (IBD) has been confirmed. However, the role of protein consumption in IBD remains controversial. This research aimed to explore the effects of milk-based protein (MBP), potato protein (PP), and mixed protein (MP) on the recovery of mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). MP alleviated UC symptoms through reducing colon shortening and tissue damage, decreasing neutrophil infiltration, maintaining the mucous layer integrity, and suppressing the expression of TNF-α, IL-17A, IL-6, and IL-1β. MBP and PP decreased the colon shortening and IL-1β levels but PP increased the MUC2 expression. Additionally, the gut microbial structure and composition were altered after different proteins supplement. Compared to DSS-treated mice, MP-treated mice showed that increased abundances in Coprococcus and Bifidobacterium and decreased abundances in Sutterella, Lactobacillus, and Akkermansia. MBP increased the proportion of Bifidobacterium and reduced Sutterella, but PP increased Ruminococcus and Bifidobacterium and decreased Adlercreutzia. Correspondence analysis of gut microbial composition to determine the effects of protein diets on immune response and pathological characteristics also verified the interaction between gut microbiota and alleviation of colitis. These results provide a theoretical basis for the selection of raw materials for clinical enteral nutrition preparations and potential use for potato protein wastes.