Do vitamins and supplements prevent cancer?

There is not enough proof that taking multivitamins, single vitamins, or minerals can prevent cancer. Several have been studied but have not been shown to lower cancer risk, including vitamins B6, B12, E, C, and D, beta carotene, folic acid, and selenium.

In fact, one large study — the Selenium and Vitamin E Cancer Prevention Trial (SELECT) — found that vitamin E taken alone increased the risk of prostate cancer, and the risk continued even after the men stopped taking it. Taking selenium with vitamin E, or selenium alone, did not increase that risk.

Research continues on some supplements. Because results are still not clear and some supplements can carry risks, it is a good idea to talk with your healthcare team before starting any supplement to try to prevent cancer.