How much green tea does it take for an anti-cancer effect?
I’m often asked how much an ‘anticancer’ diet will reduce the risk that cancer will progress or relapse.
I’m going to answer this in three stages, beginning today, with the quantitative data on green tea.
Note that post-menopausal hormone replacement therapy increases the risk of developing breast cancer by between 15 and 40 percent (a factor of 1.15 – 1.4). Smoking, in comparison, increases the risk of developing lung cancer 15 to 35 years later by a factor of roughly 15. What about a diet with more green tea? With a lower glycemic index? With fewer omega-6s and more omega-3s? We can gather a rough idea of these figures from various studies of nutrition – not performed on animals, as most research studies are, but in human populations.
Concerning green tea, we can for example look at two studies. In one, Japanese women already diagnosed with breast cancer, whose disease was still at an early stage (non-metastasized) and who consumed at least three cups of green tea a day, had 57% fewer relapses than women who drank one cup or less per day (Inoue et al., 2001). Another Japanese study, Japan being the country where studying consumption of green tea is easiest, showed that men with prostate cancer notably benefited from the consumption of FIVE or more cups of tea a day. This reduced by 50% the risk that their prostate cancer would progress to an advanced stage. (Kurahashi et al., 2007)
As Dr. Béliveau has written in the Lancet (2004), the quantity of green tea polyphenols obtained by a daily consumption of just three cups (size 4 oz or 120 ml – the standard European cup size) is sufficient to block most activity by the VEGF receptor. This receptor allows cancer cells to invade neighboring tissue, and also stimulates the manufacture of new blood vessels which they need in order to develop as dangerous tumors. Many of the famous “targeted cancer treatments” developed by the pharmaceutical industry also concentrate on blocking this receptor by other biochemical processes.
1. Inoue M, Tajima K, Mizutani M, et al. 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. Cancer Letters 2001;167(2):175-82.
2. Kurahashi N, Sasazuki S, Iwasaki M, Inoue M, Shoichiro Tsugane for the JSG. Green Tea Consumption and Prostate Cancer Risk in Japanese Men: A Prospective Study. Am J Epidemiol 2007;167(1):71-7.
3. Beliveau R, Gingras D. Green tea: prevention and treatment of cancer by nutraceuticals. Lancet 2004;364(9439):1021-2.