Vitamin-mediated immune regulation in the development of inflammatory diseases.

Mucosal tissues and especially the intestine are constantly exposed to abundant non-self materials yet simultaneously establish immune homeostasis to prevent excessive inflammatory responses. The maintenance of intestinal homeostasis is achieved by a harmonized immune network mediated by endogenous factors (e.g., cytokines and chemokines) and exogenous factors (e.g., commensal bacteria and dietary matter). Specifically, vitamins from such exogenous sources function immunologically in the control of homeostatic immune responses; thus, their deficient or excessive intake is associated with the development of inflammatory diseases. The focus of this review is the immunologic functions of vitamins B3, B9, A, and D in the regulation and development of inflammation.