Antioxidant Supplements May Improve Health of Chemotherapy Patients

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By VRP Staff

A new review of the medical literature has found that antioxidant supplements may help improve cancer survival rates, tumor response, and the patient"s ability to tolerate chemotherapy.

The reviewers found 19 trials that met all evaluation criteria, such as the use of randomized trials with a control group and the reporting of tumor response and survival data. The trials included a total of 1,554 participants. Antioxidants evaluated were glutathione (7 trials), melatonin (4 trials), vitamin A (2 trials), an antioxidant mixture (2 trials), vitamin C (1 trial), N-acetyl cysteine (1 trial), vitamin E (1 trial) and ellagic acid (1 trial). Subjects of most studies had advanced or relapsed disease.

After examining the data, the researchers determined that cancer subjects taking antioxidants had similar or better survival rates than the control subjects. Furthermore, none of the trials supported the theory that antioxidant supplements diminish the effectiveness of chemotherapy.

Of the 17 trials that assessed chemotherapy toxicities, including diarrhea, weight loss, nerve damage and low blood counts, 15 concluded that the antioxidant group suffered similar or lower rates of these side effects than the control group.

According to the reviewers, a reduction in side effects may stop patients from having to reduce their chemotherapy dosing, interrupt scheduled treatments, or abandon treatment altogether. Consequently, antioxidants’ ability to reduce these side effects may have a favorable effect on treatment outcomes.

Debate has existed over whether cancer patients should take antioxidants due to the possibility that they will cancel out the effects of some chemotherapy drugs. Many have claimed that antioxidants scavenge the reactive oxygen species integral to the activity of certain chemotherapy drugs, thereby diminishing treatment efficacy. However, the researchers of the current review believe that the results indicate there is no scientific support for the objection to using antioxidants during chemotherapy, especially since it appears that these supplements may help decrease the side effects of chemotherapy.

Reference:
Block KI, Koch AC, Mead MN, Tothy PK, Newman RA, Gyllenhaal C. Cancer Treatment Reviews (Elsevier). Impact of antioxidant supplementation on chemotherapeutic efficacy: A systematic review of the evidence from randomized controlled trials. Published online 28 March 2007.