Just when vitamin D was beginning to look like the cure-all where cancer is concerned—many studies have proclaimed it instrumental in preventing or slowing cancers of the skin, colon, breast, and prostate, to name a few—a new study announced by the U.S. National Cancer Institute says increased vitamin D consumption does not correlate with reduced cancer mortality. The one exception, according to the study’s authors, may be cancer of the colon.
The study did not involve new research. Rather, it analyzed data for 16,818 subjects who participated in the Third National Health and Nutrition Examination Survey, which inducted participants between 1988 and 1994 and followed them through 2000. Participants were given blood tests to establish a baseline at the beginning of their enrollment; it was from these blood tests that the level of vitamin D (as 25-hydroxyvitamin D) was tested against decreased cancer mortality and found to be lacking. In the case of colorectal cancer, however, the study found a 72 percent reduced risk of death when vitamin D levels were sufficiently high.
The study, authored by D. Michal Freedman, Ph.D., of the National Cancer Institute in Bethesda, Md., and colleagues, was published in this month’s Journal of the National Cancer Institute. The authors believe it is the first study to test vitamin D blood levels—as opposed to supplement consumption—against cancer mortality.
