Abstract
BACKGROUND: The prevalence of vitamin D (VD) deficiency in adults with inflammatory bowel disease (IBD) has been reported to be very high. In adults with ulcerative colitis (UC) it has been estimated to be around 45-50%, and in the case of Crohn's disease (CD) it ranges from 35-100%. This systematic review aimed to address the effects of VD in inducing remission in patients with CD and UC. METHODS: PubMed, Embase, and Cochrane were searched, and PRISMA guidelines were followed. Nine studies with active disease subjects were evaluated; 5 of them investigated patients with UC, 2 studied patients with CD, while 2 studies included patients with both diseases. RESULTS: The studies show that oral daily doses from 1000 IU can raise VD levels above 20 ng/mL in patients with active CD or UC. Doses close to 50,000 IU per week are sufficient to raise VD levels above 40 ng/mL. Moreover, daily doses from 2000 IU can be related to improvements in the clinical scores of the disease and improvement in patients' quality of life. CONCLUSION: It is challenging to define the best doses of VD as a therapeutic adjunct to induce remission in IBD patients, as there are biases in the inclusion of studies, since the route of administration of the VD can vary, as well as the doses and the time of use.