Vitamin D Status in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), comprising crohn's disease (CD) and ulcerative colitis (UC), is a a chronic, relapsing-remitting systemic disease. Vitamin D is a secosteroid hormone that possesses immunomodulatory properties and has been demonstrated to potentially influence inflammatory bowel disease (IBD) pathogenesis and activity.

Inflammatory bowel disease (IBD), comprising crohn's disease (CD) and ulcerative colitis (UC), is a a chronic, relapsing-remitting systemic disease and it is increasing sharply with rapidly increasing proportion in developing countries., and the common medications are not effective for most patients.The key underlying pathogenic mechanisms for both diseases is a dysregulated host immune response to commensal intestinal flora in genetically susceptible individuals.Vitamin D is a fat-soluble vitamin, a secosteroid hormone whose active form, calcitriol or 1,25-dihydroxyvitaminD3 (1,25(OH)2D3) plays important roles in immune regulation, particularly involving the innate immune system, cell differentiation and intercellular adhesion, promotes the production of anti-microbial peptides, including β-defensins and cathelicidins, the shift towards Th2 immune responses, and regulates autophagy and epithelial barrier integrity.The relationship between vitamin D deficiency and IBD is bidirectional that vit D with its immunomodulatory effects influence IBD pathogenesis and activity and IBD itself can lead to vitamin D deficiency.Vitamin D deficiency has associated with increased IBD activity scores, lower quality-of-life, an increased risk of IBD-related surgery and increased hospitalizations.\[4\]. Vitamin D downregulate powerful proinflammatory cytokines, such as TNF, which enhance the durability of anti-TNF therapy in IBD and its deficency has been found to be associated with earlier cessation of anti-TNFα therapy( loss of response to biologic therapy.