Vitamin D Supplementation in Crohn's Patients

The incidence of autoimmune diseases like inflammatory bowel disease (IBD) has increased in developed countries over the last 50 years. We propose that decreased outdoor activity and increased pollution and diets that lack adequate vitamin D have combined to create large fluctuations in vitamin D status in developed countries and especially in populations that experience winter. Experimentally we've shown that changes in vitamin D status results in more severe forms of experimental IBD. In addition, active vitamin D (1,25(OH)2D3) completely blocks the development of experimental IBD. The vitamin D hypothesis proposes that vitamin D regulates the development and function of the immune system and that changes in vitamin D status affect the development of the resultant immune response and the development of diseases like IBD. Our hypothesis is that because of low dietary vitamin D intakes and malabsorption of many nutrients, Crohn's patients will have low circulating vitamin D levels that are detrimental for their health. We plan to give Crohn's patients 1000 IU of vitamin D/d and determine whether this dose is well tolerated, induces an increase in circulating vitamin D levels and has any additional health benefits (improved bone markers, Crohn's disease activity scores, inflammatory markers).