SATURDAY October 13, 2007 (Foodconsumer.org) -- Drinking lots of green tea a day was linked with reduced risk of advanced prostate cancer, but not localized prostate cancer, Japanese researchers found, adding to a growing body of evidence suggesting that green tea may provide protection against cancer.

The study published in the American Journal of Epidemiology found those who drank five or more cups of green tea a day were 48 percent less likely to develop advanced prostate cancer.   The association was not seen for localize prostate cancer though.

The study was conducted by researchers from Japan's National Cancer Center and involved 49,920 Japanese men aged from 40 to 69 who participated in the Japan Public Health Center-based Prospective Study.

Green tea contains 30 to 40 percent of water-extractible polyphenols. In comparison, black tea contains only 3 to 10 percent.   Epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin are the four polyphenols that are most abundantly found in tea leaves.

Early studies have found green tea provides protection against Alzheimer's disease and helps weight loss in addition to its anticancer properties.   Laboratory and animal studies provide convincing evidence that green tea components like EGCG protect against cancer by promoting apoptosis.

In the United States, 218,890 men will be diagnosed with prostate cancer and 27,050 will die of the disease.   Eating fruits and vegetables are known to reduce the risk, according to a US government health agency.

Source: American Journal of Epidemiology

Published on-line ahead of print, doi:10.1093/aje/kwm249

"Green Tea Consumption and Prostate Cancer Risk in Japanese Men: A Prospective Study"

Norie Kurahashi, S. Sasazuki, M. Iwasaki, M. Inoue and S. Tsugane for the JPHC Study Group