The role of vitamin D3 and vitamin B9 (Folic acid) in immune system

Background and aims: Vitamins are essential constituents of our diet that Longley have been known to influence the immune system. Vitamin D3 and B9 have received particular attention in recent years as these vitamins have been shown to have an unexpected and crucial effect on the immune response. 1, 25(OH)2D3 metabolizing enzymes and vitamin D receptor (VDR) are present in many cell types including various immune cells such as antigen-presenting-cells, T cells, B cells. Methods: In this mini review, we study 30 novel articles since 2009 to 2015 about the essential roles of vitamins in modulating a broad range of immune processes, such as lymphocyte activation, T-helper-cell differentiation and regulation of the immune response. Results: 1, 25(OH)2D3 has direct effect on CD4+ T (T-helper) cells for suppressing various cytokines such as IFN-γ, IL-17, IL-21 and IL-22, while enhancing the regulatory Tcells. In vitro studies show that Treg cells could be differentiated from naive T cells in vitamin B9-reduced condition. Conclusions: These findings provide a new link between diet and the immune system, which could maintain the immunological homeostasis and clarify the beneficial roles of vitamins in informing the design of vitamin analogs as pharmacologic agents for the generation and maintenance of a healthy immune condition.