Peyrin-Biroulet L, Oussalah A, Bigard MA. Med Hypotheses 2009;73:94–6.
In this article, Peyrin-Biroulet et al. review the evidence for a protective role of sunlight and endogenous/dietary vitamin D in the development of Crohn’s disease, including in vivo studies demonstrating a therapeutic effect of vitamin D in ameliorating the severity of colitis. The authors conclude that vitamin D supplementation and/or heliotherapy may be useful in the treatment of Crohn’s disease, although additional investigations into such treatments are required.
The pathogenesis of Crohn’s disease remains largely unknown but the contribution of luminal bacteria flora, and of genetic, environmental, and immune regulatory factors with a Th1-type cytokine profile, is evident in the initiation and perpetuation of the disease. Epidemiological studies have highlighted that low vitamin D levels are linked with autoimmune disorders including multiple sclerosis, type 1 diabetes, and rheumatoid arthritis. Interestingly, a recent study demonstrated that only 22% of Crohn’s disease patients had optimal serum levels of vitamin D, suggesting a similar possible etiological role for this vitamin in IBD [1].