Should I Take Antioxidant Supplements If I'm Undergoing Cancer Treatment?

Linda A. Lee, M.D,

Question: Should I take antioxidant supplements if I'm undergoing cancer treatment?

Answer:Antioxidants are substances that work against something called reactive oxygen species. These are byproducts of biochemical reactions that occur every day in all of our cells. And our body has natural antioxidants that it produces to counteract these. There's a lot of interest in using antioxidants by patients who have cancer because the feeling is that perhaps somehow they are preserving their normal tissue and reducing the risk of having a complication or side effect related to chemotherapy. Such antioxidants include superoxide dismutase, vitamin A, C, and E, milk thistle and ginseng for example. There is no clear evidence that antioxidants are truly helpful for patients who have cancer when taken in the supplement form in this way. I would say if you were interested in boosting antioxidants in your body that the best way to do it is through a healthful diet. There is also concern that the use of antioxidants in some patients undergoing cancer therapy might actually be detrimental, and the reason for this is that there are some forms of chemotherapy and radiation that depend on the production of reactive oxygen species to actually be effective. So theoretically, if you're taking an antioxidant supplement, you may be reducing the effectiveness of your cancer therapy. So I think if you're very interested in using an antioxidant that you need to have a discussion with your oncologist about this. It's not clear when the best time is to use the antioxidants. I would say certainly to avoid them while you're getting active chemotherapy or radiation.