The potential therapeutic role of vitamin D in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is defined as a relapsing and remitting condition characterized by chronic inflammation at different sites in the gastrointestinal tract. Crohn's disease (CD) and ulcerative colitis (UC) represents the two major forms of IBD. Even though IBD pathophysiology is still not fully understood, genetic factors, environmental factors, dysregulation of both innate and adaptive immune responses, alterations in gut microbiota composition, excessive consumption of saturated fats and cumulative antibiotic exposure have all been suggested to play a role in the development of this condition. Amongst the environmental factors, vitamin D deficiency has been suggested to participate in IBD pathophysiology. Indeed, vitamin D exerts several pleiotropic effects beyond its well-established regulation of bone and calcium homeostasis, including anti-infective, anti-inflammatory and immunomodulatory effects as well as maintenance of gastrointestinal barrier integrity and beneficial gut microbiota composition. In this narrative review, we discuss the role of vitamin D deficiency in IBD pathophysiology as well as the potential therapeutic use of vitamin D for the management of IBD.