This study compared the effects of five isocaloric dietary protein sources — beef (BP), egg white (EP), casein (CP), soy (SP), and pea (PP) — on colitis severity in acute (DSS-induced) and chronic (IL-10-deficient) murine models, focusing on gut microbiome and bile acid mechanisms.
Beef protein–fed mice developed the most severe colitis; pea protein–fed mice had the mildest inflammation. BP diet reduced *Lactobacillus johnsonii* and *Turicibacter sanguinis*, expanded *Akkermansia muciniphila*, thinned the mucus layer, and raised primary and conjugated fecal bile acids. Taurocholic acid alone worsened colitis in pea-fed mice. Adding dietary psyllium to a BP diet reversed these effects and reduced inflammation.
Findings are from murine models only — direct translation to human IBD is unproven. Protein isolates were used rather than whole foods, which may not capture all bioactive components of red meat. The study does not fully isolate whether *A. muciniphila* expansion is harmful or a downstream marker.
For IBD patients, reducing red meat and shifting toward plant-based proteins (especially pea protein) may help limit gut inflammation — and adding psyllium fiber may partially offset harm from animal-protein diets. These findings support dietary counseling that emphasizes both protein source and fiber intake, pending human trial confirmation.
