Green tea contains the active ingredient polyphenol, which has a subgroup known as catechins. Catechins are powerful antioxidants and may have cancer-preventative effects. A large study in Japan found that males aged between 40 and 69 who drank five cups of green tea daily were less likely to develop advanced prostate cancer than those who drank only one1.
However, despite promising results of the current study, it does not provide strong enough evidence that green tea can definitely reduce the risk of prostate cancer. This is due to the differences between the people who drank green tea frequently and those who drank it occasionally such as their eating habits and lifestyles. There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention by far2.
Overall, drinking green tea appears to be safe at moderate, regular and habitual use. Those who enjoy a cup of green tea should continue its consumption.
- Kurahashi N, Sasazuki S, Iwasaki M et al. Green Tea Consumption and Prostate Cancer Risk in Japanese Men: A Prospective Study. Am J Epidemiol 2008; 167:71-77
- Boehm K, Borrelli F, Ernst E, Habacher G, Hung SK, Milazzo S, Horneber M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev. 2009; Jul 8; (3)