Vitamin D and colon cancer

Calcitriol, 1 alpha, 25-dihydroxyvitamin D-3 (1,25 (OH) D-2(3)), the most active form of vitamin D, is a pleotropic hormone with a wide range of biological activities. Due to its ability to regulate calcium and phosphate metabolism, 1,25D(3) plays a major role in bone health. In addition, 1,25D(3) binds to the vitamin D receptor and thereby regulates the expression of a number of genes which control growth, differentiation and survival of cancer cells. In agreement, the levels of vitamin D-3 appear to be an essential determinant for the development and progression of colon cancer and supplementation with vitamin D-3 is effective in suppressing intestinal tumorigenesis in animal models. Vitamin D-3 has been estimated to lower the incidence of colorectal cancer by 50%, which is consistent with the inverse correlation between dietary vitamin D-3 intake or sunlight exposure and human colorectal cancer. Several studies confirmed that increasing vitamin D-3 lowers colon cancer incidence, reduces polyp recurrence, and that sufficient levels of vitamin D-3 are associated with better overall survival of colon cancer patients. Vitamin D regulates the homeostasis of intestinal epithelium by modulating the oncogenic Wnt signaling pathway and by inhibiting tumor-promoting inflammation. Both activities contribute to the ability of 1,25D(3) to prevent the development and progression of colon cancer. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.