Should I stop drinking green tea during chemotherapy to avoid consuming too many antioxidants?
There are two research studies (1,2) that have shown increased survival of women in Japan with stage I and II breast cancer related to how much green tea they drank after their diagnosis (drinking 3 or more cups/day led to increased survival).
A different study yet has shown increased survival of women in China with epithelial ovarian cancer who consumed at least one cup of green tea daily compared to women who drank no green tea (3).
None of these studies made any mention of women stopping their consumption of green tea during therapy. Research continues to evaluate the various components of green tea and the multiple ways that these molecules influence cancer cells, not just any effects of the antioxidant capacity.
Until research has given us more information about potential benefits and toxicity of green tea extracts, I would recommend consuming green tea as a beverage rather than relying on green tea extracts for anti-cancer benefit. One recent in vitro study using a green tea extract showed unexpected adverse effects by promoting lung cancer cell growth at high doses. (4) Another study which was a clinical trial of green tea extracts at a dose of 250 mg twice daily showed no significant benefit when used in men with hormone-refractory prostate cancer. (5)
I would also suggest seeking the input and recommendations from the Registered Dietitian (RD) at your cancer treatment facility for a full assessment of your individualized nutritional needs and goals.
Lastly, I also suggest reading what I have to say on the following faq, which also addresses this question in a more general manner: http://www.cancerrd.com/faqs/faq37.htm
(1) Jpn J Cancer Res. 1998 Mar;89(3):254-61.
Influence of drinking green tea on breast cancer malignancy among Japanese patients. Nakachi K, Suemasu K, Suga K, Takeo T, Imai K, Higashi Y.
(2) Cancer Lett. 2001 Jun 26;167(2):175-82.
Regular consumption of green tea and the risk of breast cancer recurrence: follow-up study from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC), Japan.
Inoue M, Tajima K, Mizutani M, Iwata H, Iwase T, Miura S, Hirose K, Hamajima N, Tominaga S.
(3) Int J Cancer. 2004 Nov 10;112(3):465-9.
Green tea consumption enhances survival of epithelial ovarian cancer. Zhang M, Lee AH, Binns CW, Xie X.
(4) J Nat Prod. 2004 Dec;67(12):2063-9.
Hypoxia-inducible factor-1 activation by (-)-epicatechin gallate: potential adverse effects of cancer chemoprevention with high-dose green tea extracts. Zhou YD, Kim YP, Li XC, Baerson SR, Agarwal AK, Hodges TW, Ferreira D, Nagle DG.
(5) Urol Oncol. 2005 Mar-Apr;23(2):108-13.
prospective clinical trial of green tea for hormone refractory prostate
cancer: An evaluation of the complementary/alternative therapy approach.
Choan E, Segal R, Jonker D, Malone S, Reaume N, Eapen L, Gallant V.
These questions and answers are intended to be of a general informative nature. Please consult with the Registered Dietitian in your cancer center or your health care provider for nutritional advice that can be individualized to your specific medical condition.
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