Protective links between vitamin D, inflammatory bowel disease and colon cancer

Abstract

Vitamin D deficiency has been associated with a wide range of diseases and multiple forms of cancer including breast, colon, and prostate cancers. Relatively recent work has demonstrated vitamin D to be critical in immune function and therefore important in inflammatory diseases such as inflammatory bowel disease (IBD). Because vitamin D deficiency or insufficiency is increasingly prevalent around the world, with an estimated 30%-50% of children and adults at risk for vitamin D deficiency worldwide, it could have a significant impact on IBD. Epidemiologic studies suggest that low serum vitamin D levels are a risk factor for IBD and colon cancer, and vitamin D supplementation is associated with decreased colitis disease activity and/or alleviated symptoms. Patients diagnosed with IBD have a higher incidence of colorectal cancer than the general population, which supports the notion that inflammation plays a key role in cancer development and underscores the importance of understanding how vitamin D influences inflammation and its cancer-promoting effects. In addition to human epidemiological data, studies utilizing mouse models of colitis have shown that vitamin D is beneficial in preventing or ameliorating inflammation and clinical disease. The precise role of vitamin D on colitis is unknown; however, vitamin D regulates immune cell trafficking and differentiation, gut barrier function and antimicrobial peptide synthesis, all of which may be protective from IBD and colon cancer. Here we focus on effects of vitamin D on inflammation and inflammation-associated colon cancer and discuss the potential use of vitamin D for protection and treatment of IBD and colon cancer.

Keywords: Vitamin D; Inflammatory bowel disease; Colitis; Colon cancer; Inflammation-associated colon cancer; Mouse models

Core tip: Vitamin D is inversely related to inflammation-associated diseases such as inflammatory bowel disease (IBD) and colon cancer. As vitamin D deficiency and insufficiency are prevalent worldwide, it can significantly impact risk and progression of these diseases. Here we provide an overview of human epidemiologic and animal studies linking vitamin D, IBD and colon cancer. We also review potential mechanisms of vitamin D action that were elucidated by using animal models. Finally, we address current knowledge gaps in this field of research to help determine the potential benefits and risks of using vitamin D to prevent and/or treat IBD and cancer.