Researchers at the University of California at Los Angeles were able to detect tea polyphenols in prostate tissue after a very limited consumption of tea. More importantly, the scientists found that prostate cancer cells grew more slowly when placed in a medium containing blood of men who had consumed either green or black tea for five days compared to blood collected before the men began their tea-drinking regimen.

Dr Susanne Henning of UCLA says the research team focused on the possible effect of tea polyphenols on factors named polyamines and the enzymes responsible for the production of polyamines. Elevated levels of polyamines have been associated with malignancy in humans, including prostate cancer.

Five days before they were to undergo radical prostatectomy, 20 men with prostate cancer were randomly assigned to consume daily either five cups of green tea, five cups of black tea, or diet or regular soda containing no tea polyphenols. Their blood serum was then collected and added to prostate tissue samples. When the scientists compared the level of total polyamine to the total polyphenol content, the tea drinkers showed a significant negative correlation – the more tea components in the tissue, the less of the polyamines associated with malignancy. There was also a significant decrease in how fast new cancer cells appeared for the men who had consumed either green or black tea. This study suggests that both black and green tea are promising natural dietary supplements useful for chemoprevention of prostate cancer, according to Dr. Henning.

Federation of American Societies for Experimental Biology, Apr 18, 2004