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).