In a thorough review of randomized studies evaluating the effects of taking antioxidants with chemotherapy, antioxidant supplementation was found to reduce the toxic effects of chemotherapy. The researchers reviewed 33 studies (which included 2,446 subjects). Twenty-four showed that taking the antioxidants decreased the toxic side effects of chemotherapy.
Antioxidants used in the studies included: glutathione, melatonin, vitamin A, N-Acetyl Cysteine, vitamin E, selenium, L-carnitine, coenzyme Q10, and ellagic acid. Five of the studies found that subjects taking antioxidants were able to complete more full doses of chemotherapy, The authors conclude, "This review provides the first systematically reviewed evidence that antioxidant supplementation during chemotherapy holds potential for reducing dose-limiting toxicities. However, well-designed studies evaluating larger populations of patients given specific antioxidants defined by dose and schedule relative to chemotherapy are warranted."
While these studies are being done, I encourage my cancer patients to get solid overall nutritional support with a good multivitamin powder. I also like to augment immune function and recommend the immune boosting supplement thymic protein 1 serving 3x a day for 3 months (and then may decrease to once daily) for those with cancer. I then add other nutrients based on the specific cancer type.
As part of the ongoing attempt to discourage natural supplements, some physicians have been told that antioxidants may decrease the effectiveness of some chemo and radiation therapies (that kill cancer through oxidation). My reading of the science over the years suggests that people who supplement live longer. A simple compromise. I leave off the supplements for a week before and after therapies if the oncologist voices a concern. I have found that trying to starve you to starve and kill the cancer cells is a losing proposition in the long term. People do best when their own defenses are kept strong, so they can remove the cancer while working alongside with the prescription medical therapies.
"Impact of antioxidant supplementation on chemotherapeutic toxicity: A systematic review of the evidence from randomized controlled trials," Block KI, Koch AC, et al, Int J Cancer, 2008; 123(6): 1227-1239.