If you are a cancer survivor, consult your doctor about any dietary supplements you’re taking.
Some research suggests that large amounts of zinc or antioxidants, for example, may actually promote the recurrence of certain cancers. Survival rates have risen in the U.S., and thus there are many more long-term cancer survivors. A study from Duke University Medical Center found that 75 percent of cancer survivors over 65 take dietary supplements. However, the American Institute for Cancer Research and the World Cancer Research Fund recommend against taking high-dose supplements as a way to reduce the risk of cancer or its recurrence.
In particular, if you are undergoing treatment for cancer, such as chemotherapy or radiation, you should avoid antioxidant supplements. According to a review published in the Journal of the National Cancer Institute, some studies have found that antioxidants (such as vitamin C and E and beta carotene) seem to reduce the side effects of treatment, but others show they may actually protect tumor cells and thus reduce patient survival. Though not all studies have been of high quality, the potential harm outweighs the potential benefits. “Can’t hurt, might help” does not apply here.
Cancer patients should refrain from taking supplements or at least be sure their doctors know and approve what they are taking.