BEIJING, Dec. 20 (Xinhuanet) -- Drinking five or more cups of green tea a day may reduce the risk of developing advanced prostate cancer, according to a Japanese study published in the American Journal of Epidemiology Wednesday.

    An analysis finds the risks of having advanced prostate cancer was 50 percent lower for men who drink five or more cups of green tea a day compared with those who have less than one cup, the study said.

    "This does not mean that people who drink green tea are guaranteed to have reduced risk of advanced prostate cancer," said Norie Kurahashi, a scientist who took part in the study.

    "We are just presenting our results. But the study does point to the hope that green tea reduces the risk of advanced prostate cancer," Kurahashi said.

    Researchers from Japan's health ministry surveyed 49,920 men aged 40-69 across the country in 1990 and 1993 and followed up on their health until 2004. During the period, the subjects were divided into groups of different consumption levels of green tea and then analyzed accordingly. 

    The result: 404 men were newly diagnosed with prostate cancer, of whom 114 had advanced cases, 271 were localized and 19 were of an undetermined stage.     

    "Green tea was not associated with localized prostate cancer," the researchers said, adding, "green tea may be associated with a decreased risk of advanced prostate cancer."

    "Catechin," a substance abundantly contained in green tea, may help reduce risks by curbing levels of testosterone, a male hormone seen as a risk factor to prostate cancer, according to researchers.

    Prostate cancer is much less common among Asian men than Western men and it may be linked to the high consumption of green tea in Asian populations, the study noted.

(Agencies)