ABSTRACT
Studies were undertaken to investigate the role of calcium in mammary carcinogenesis. In a small pilot experiment, rats fed the diets containing lower levels of calcium, phosphate, and vitamin D developed more tumors than those fed the high levels, at both low and high levels of dietary fat. In the second experiment, involving a larger number of animals, the groups fed lower levels of calcium, phosphate, and vitamin D again developed more tumors on the high-fat diet. Conversely, the lowest tumor yields were observed in the groups on diets that were low in phosphate and high in vitamin D. Since breast cancer and colon cancer have a similar geographical distribution, the same argument can be used to suggest that vitamin D and calcium may help to reduce the risk of breast cancer. The control of calcium levels in tissue is relatively complex, and there are numerous ways in which variations in these levels could influence the proliferation of cancer cells.
