Multivitamins and prostate cancer: A new worry?
About a third of American adults take some type of multivitamin on a regular basis. In nearly every case, the goal is better health. In 2003, the authoritative U.S. Preventive Services Task Force concluded that there was no firm evidence to support this hope. At the same time, though, it did not find evidence that multivitamins are harmful. Multivitamins have remained popular as a sort of insurance policy or, perhaps, as proof that hope can outweigh evidence.
The absence of benefit is one thing, the presence of harm quite another. A 2007 report in the Journal of the National Cancer Institute concludes that "our finding of a markedly increased prostate cancer risk among men using multivitamins is of concern and warrants further study." Since prostate cancer is the most common internal malignancy and the second leading cause of cancer death in men, it is indeed a concern. And since more than 50% of men at high risk for prostate cancer take supplements to ward off the disease, it's a big concern.