Vitamin D as a therapy for colitis: a systematic review.

BACKGROUND AND AIM The effect of vitamin D supplementation on immune disorders has been a topical research focus. The aim of this systematic review was to examine the current evidence of the effect of vitamin D supplementation as a therapy for colitis. METHODS The following databases were searched: MEDLINE, Pubmed, Scopus, Web of Knowledge, Cinicaltrials.gov and the Cochrane Central Register of Controlled Trials using the terms 'inflammatory bowel disease' 'Crohn's disease' 'ulcerative colitis' 'colitis' [and] 'vitamin D'. Both human and animal studies published in English language were examined. The reference lists of included studies and review articles were manually searched for any relevant studies. RESULTS Four studies were included in this systematic review. All reported an improvement in disease activity with vitamin D supplementation. The only high quality human study reported a non-significant reduction of relapse rate for Crohn's disease. No major adverse effects of vitamin D supplementation were reported. CONCLUSIONS Although there is some evidence that supplemental vitamin D, as an adjunctive treatment, may help in controlling colitis, this evidence is not enough to justify using vitamin D in treating inflammatory bowel disease (IBD). Large high quality placebo-controlled randomised controlled trials are needed to explore a possible benefit of using vitamin D in treating IBD.