Scientists at Case Western Reserve University in Cleveland, Ohio, gave either an extract of green tea or water to mice that are prone to develop metastatic (spreading) prostate cancer. The amount of tea the mice received was the equivalent of six cups of green tea a day in humans.

All of the mice given water went on to develop prostate cancer but, in those given the tea extract, there was a significant delay in the development of the disease.

The green tea-fed mice also experienced a decrease in the weight of the prostate gland itself, an inhibition of various harmful cancer growth factors and a reduction in some of the markers of proliferating prostate cells.

Clearly, the results of an animal study do not necessarily relate directly to the human experience. However, this small study adds to the now considerable bulk of evidence on the cancer-protective effects of regular green tea consumption in living things (PNAS, 2001; 98: 10350-5).