title: Vitamin D therapy in inflammatory bowel diseases: who, in what form, and how much?
abstract: BACKGROUND
  The north–south geographical gradient of inflammatory bowel disease (IBD) prevalence, its epidemiology, the genetic association of vitamin D receptor polymorphisms, and results in animal models suggest that vitamin D plays an important role in the pathogenesis of IBD.
  
  
  OBJECTIVE
  The purpose of this review was to critically appraise the effectiveness and safety of vitamin D therapy in patients with IBD.
  
  
  METHODS
  MEDLINE, Scopus and Google Scholar were searched from inception to May 20, 2014 using the terms ‘Crohn’s disease’, ‘ulcerative colitis’ and ‘vitamin D’. Results: Vitamin D deficiency is common in patients with IBD. Limited clinical data suggest an association between low vitamin D concentration and increased disease activity in both ulcerative colitis (UC) and Crohn’s disease (CD). To date, only two small open label trials and one randomized controlled trial have shown a positive effect of vitamin D supplementation on disease activity in patients with CD; no effect has been shown for UC. An optimal vitamin D supplementation protocol for patients with IBD remains undetermined, but targeting serum 25-hydroxy vitamin D [25(OH)D] levels between 30 and 50 ng/mL appears safe and may have benefits for IBD disease activity. Depending on baseline vitamin D serum concentration, ileal involvement in CD, body mass index, and perhaps smoking status, daily vitamin D doses between 1800–10,000 international units/day are probably necessary.
  
  
  CONCLUSIONS
  Increasing preclinical and clinical evidence suggests a role for vitamin D deficiency in the development and severity of IBD. The possible therapeutic role of vitamin D in patients with IBD merits continued investigation.
authors.forename: Tibor
authors.initials: T
authors.lastname: Hlavaty
authors.forename: Anna
authors.initials: A
authors.lastname: Krajcovicova
authors.forename: Juraj
authors.initials: J
authors.lastname: Payer
mesh_terms: D017281:Cost of Illness; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000191:economics; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D