We recently discussed this on another thread. It is always a topic which raises many questions. Please see below.
Re: Should I take anti-oxidants prior to, during, and post treatment?
This topic, like many in cancer care, is controversial. Generally, it is not recommended for patients undergoing chemo/radiation to take extra antioxidants--though they are not restricted in the diet. The idea is that we can consume very high doses in supplemental form vs smaller doses in food. Some research has shown that taking high dose antioxidants decreases the effectiveness of some chemotherapies. Other research has shown a synergistic effect with antioxidants enhancing certain chemotherapy drugs. I think it is important to recognize that we use the term "chemotherapy" very broadly when in reality each drug is very different in its mechanism of action and the effect of antioxidants on each of these drugs is likely different. I continue to caution patients against using high dose supplements but do recommend a diet with plenty of fruits and vegetables.
Here are two opposing reviews.
CA Cancer J Clin. 2005 Sep-Oct;55(5):319-21.
Use of antioxidants during chemotherapy and radiotherapy should be avoided.
D'Andrea GM.
Source
Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
Abstract
Many patients being treated for cancer use dietary supplements, particularly antioxidants, in the hope of reducing the toxicity of chemotherapy and radiotherapy. Some researchers have claimed, furthermore, that antioxidants also increase the effectiveness of cytotoxic therapy and have explicitly recommended their use. However, mechanistic considerations suggest that antioxidants might reduce the effects of conventional cytotoxic therapies. Preclinical data are currently inconclusive and a limited number of clinical studies have not found any benefit. Clinicians should advise their patients against the use of antioxidant dietary supplements during chemotherapy or radiotherapy. Such caution should be seen as the standard approach for any unproven agent that may be harmful.
PMID:16166076[PubMed - indexed for MEDLINE]
Integr Cancer Ther. 2006 Mar;5(1):63-82.
Should patients undergoing chemotherapy and radiotherapy be prescribed antioxidants?
Moss RW.
Source
Cancer Communications, Lemont, Pennsylvania 16851, USA.
ralph@cancerdecisions.com
Abstract
In September 2005, CA: A Cancer Journal for Clinicians published a warning by Gabriella D'Andrea, MD, against the concurrent use of antioxidants with radiotherapy and chemotherapy. However, several deficiencies of the CA article soon became apparent, not least the selective omission of prominent studies that contradicted the author's conclusions. While acknowledging that only large-scale, randomized trials could provide a valid basis for therapeutic recommendations, the author sometimes relied on laboratory rather than clinical data to support her claim that harm resulted from the concurrent use of antioxidants and chemotherapy. She also sometimes extrapolated from chemoprevention studies rather than those on the concurrent use of antioxidants per se. The article overstated the degree to which the laboratory data diverged in regard to the safety and efficacy of antioxidant therapy: in fact, the preponderance of data suggests a synergistic or at least harmless effect with most high-dose dietary antioxidants and chemotherapy. The practical recommendations made in the article to avoid the general class of antioxidants during chemotherapy are inconsistent, in that if antioxidants were truly a threat to the efficacy of standard therapy, antioxidant-rich foods, especially fruits and vegetables, ought also be proscribed during treatment. Yet no such recommendation is made. Furthermore, the wide-scale use by both medical and radiation oncologists of synthetic antioxidants (eg, amifostine) to control the adverse effects of cytotoxic treatments is similarly overlooked. In sum, this CA article is incomplete: there is far more information available regarding antioxidant supplements as an appropriate adjunctive cancer therapy than is acknowledged. Patients would be well advised to seek the opinion of physicians who are adequately trained and experienced in the intersection of 2 complex fields, that is, chemotherapeutics and nutritional oncology. Physicians whose goal is comprehensive cancer therapy should refer their patients to qualified integrative practitioners who have such training and expertise to guide patients. A blanket rejection of the concurrent use of antioxidants with chemotherapy is not justified by the preponderance of evidence at this time and serves neither the scientific community nor cancer patients.