Vitamin D Supplementation Cuts Cancer Risk

In a related study, in which participants were supplemented with vitamin D, there was a significant decrease in cancer incidence over a three-year period. Researchers at Creighton University gave 1,179 women over 55 years of age either calcium (1,400-1,500 mg/day), calcium and vitamin D (same dose calcium plus 1,100 IU/day vitamin D), or placebo. The number of individuals in the calcium plus vitamin D group had a significantly reduced incidence of cancer during the study. The relative risk of developing cancer during the three years of the study in this supplemented group was 0.23 compared to the placebo group, which equates to a 77% protective effect. When the calcium-only group was compared with the calcium-plus-D group, the protective effect was deemed to be due to the vitamin D. However, in their conclusions the authors state, "Improving calcium and vitamin D nutritional status substantially reduces all-cancer risk in postmenopausal women."

Lappe JM, Travers-Gustfason D, Davies KM, et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr 2007;85:1586-1591.