Dietary protein source mediates colitis pathogenesis through bacterial modulation of bile acids

Area of Science:

• Microbiology
• Gastroenterology
• Immunology

Background:

• Dietary recommendations for inflammatory bowel diseases (IBD) are limited.
• Red meat consumption is linked to increased IBD incidence and relapse.
• Plant-based diets may mitigate gut inflammation, but underlying mechanisms are unclear.

Purpose of the Study:

• To investigate the differential effects of plant- vs. animal-derived proteins on gut inflammation.
• To elucidate the mechanisms by which beef protein promotes colitis in a murine model.

Main Methods:

• Murine colitis models were fed diets with beef protein (BP) or pea protein (PP).
• Microbiota manipulation (depletion, transplantation) was used to assess microbial mediation.
• Fecal bile acid (BA) profiles and mucus layer integrity were analyzed.
• The impact of psyllium supplementation was evaluated.

Main Results:

• BP-fed mice exhibited severe colitis, while PP-fed mice showed mild inflammation.
• BP-induced colitis was microbially-mediated.
• BP feeding altered gut microbiota composition and reduced mucus layer quality.
• Elevated fecal bile acids were observed in BP-fed mice, and taurocholic acid exacerbated colitis.
• Psyllium protected against BP-mediated inflammation and normalized BA profiles.

Conclusions:

• The protein component of red meat may contribute to colitis promotion.
• Microbial and bile acid alterations are key mechanisms in BP-induced gut inflammation.
• Dietary interventions like psyllium may offer therapeutic potential for IBD by modulating gut environment.