If you have or have had cancer or have a family history of it, it’s easy to fall for the anti-cancer claims made for countless dietary supplements in ads and especially online and on social media. It’s illegal to make anti-cancer claims—or other medical claims—for such products, and the FDA and FTC keep going after the marketers. But they don’t have the resources to keep up, especially when it comes to the thousands of ever-changing sites on the Internet. It’s like whack-a-mole—the regulators hit one product, and three more pop up elsewhere. None of the products, at least none that we’ve seen, have relevant clinical evidence supporting their claims—only scientific-sounding gobbledygook, testimonials, and other obfuscation designed to part you from your money.
In its latest crackdown, the FDA warned 14 U.S. companies about more than 65 supplements and other products that “fraudulently claim to prevent, diagnose, treat, or cure cancer.” The supplements contain everything from megadoses of vitamin C and extracts of garlic, green tea, and mushrooms to countless other herbs, vitamins, and “proprietary formulas.” In response, the companies will likely tone down their claims (for a while) or simply rename and repackage their snake oils and promote them on new websites.
Bottom line: There are no cancer cures or preventives waiting for you in the supplements aisle or on the Internet. In fact, cancer survivors and those undergoing treatment for cancer should be particularly wary of supplements. Indeed, some research suggests that large amounts of zinc, folate, or antioxidants, for example, might actually promote the recurrence of certain cancers or interfere with chemotherapy. Buyer beware.
Also see Cancer and Supplement Safety.