ABSTRACT
This chapter determines: if calcium and vitamin D modulate carcinogenesis at multiple anatomic sites or whether their chemopreventive effects are a phenomenon limited to the colon, and if this dietary modulation is only possible in the presence of high-fat consumption. It demonstrates a clear-cut benefit in an experimental animal model of supplementation with either calcium or vitamin D, which protects against the enhanced development of tumors. The series of dietary experiments described the following: Supplemental calcium or vitamin D3 at only twice the recommended allowance for rats appears to inhibit the 20% corn oil promotion of dimethylhydrazine-induced colorectal tumors. Although this study did not discretely divide the stages of initiation and promotion, it is obvious that a high-fat diet enhanced colon tumorigenesis in this study. While dietary manipulation of calcium and vitamin D levels can modulate the tumor response in the rat colon model, no effects can be seen in the mouse skin model.
