Consuming green tea may reduce the risk of developing advanced prostate cancer. A Japanese cohort study followed 49,920 men aged 40-69 years over 14 years. All had completed a questionnaire at baseline that included information about their green tea consumption.

Consumption of green tea was associated with a dose-dependent decrease in the risk of developing advanced-stage prostate cancer. The risk of advanced prostate cancer was reduced by half in those men who drank five or more cups of green tea per day, compared with those who drank less than one cup a day.

Green tea consumption and prostate cancer risk in Japanese men: a prospective study. Am J Epidemiol. 2008 Jan 1;167(1):71-7.