Ketogenic diet potentiates colitis via altering the gut microbiota and activating the innate gd17 T cell response_2 weeks metagenome

Ketogenic diets (KD) are widely recognized for their immunomodulatory and metabolic benefits, but their effects on inflammatory bowel disease remains controversial. We demonstrate that KD maintains homeostasis under physiological conditions but exacerbates colitis by triggering a ketogenesis-microbe-immune cascade upon mucosal injury. Specifically, KD elevates luminal beta-hydroxybutyrate (b-HB), promoting expansion of Thomasclavelia spiroformis (T. spiroformis), which activates colonic gd17 T cells via cell wall components, driving IL-17A-mediated inflammation.