Men at high risk of prostate cancer can reduce their chances of having the disease by drinking green tea.
The researchers, led by Nagi Kumar, an Indian-origin scientist from Moffitt Cancer Center, US, assessed the safety and effectiveness of the active components in green tea to prevent prostate cancer development in men who have pre-malignant lesions.
The researchers administered decaffeinated green tea capsules called Polyphenon E twice a day that contained a mixture of green tea substance called 'catechins'. The effects of Polyphenon E in 49 men were compared to placebo tablets in 48 men over a one-year treatment period.
Laboratory studies have shown that catechins inhibit cancer cell growth, motility and invasion, and stimulate cancer cell death.
The researchers found that people who had taken the green tea capsule had a significant decrease in prostate-specific antigen (PSA) levels.
PSA is a biomarker that in combination with other risk factors is used to screen patients for prostate cancer, and high levels signify a higher risk of prostate cancer.
Green tea catechins also prevent and reduce tumor growth in animal models, the study noted.
Twenty percent of green tea is consumed in Asian countries where prostate cancer death rates are among the lowest in the world, the researchers said.