Green tea made from tea plant leaves (Camellia sinensis) has been found to contain flavonoids, which are antioxidants in the polyphenol group. It is an abundant source of catechins. The most effective flavonoid in cancer prevention is thought to be the catechin epigallocatechin-gallate (EGCG). It is the most abundant catechin in green tea as well, making up 50-80% of the total catechins in green tea.
The CDC reported that in the US in 2006 there were 203,415 men who developed prostate cancer and 28,372 men who died from prostate cancer. It is the most common cancer among men of all races and Hispanic origin populations. It is also among the top causes of cancer death among men of all races and Hispanic origin populations.
Worldwide, prostate cancer is the second most common cancer incidence among men. Its incidence and mortality is more common in wealthy, highly developed countries. Risk and progression of prostate cancer is tied to genetic and environmental factors, especially dietary factors.
Green Tea has been used medicinally for centuries in the Far-East. Populations in countries where green tea consumption is high and tea is drunk on a daily basis have the lowest incidence of prostate cancer worldwide. There is little science-based dietary advice for the consumption of green tea to prevent prostate and other cancers.
The Research
Studies have shown that 30% of men with a certain condition known as HG-PIN would develop prostate cancer within a year of having a repeated biopsy. These results led other scientists to test the effectiveness and safety of green tea catechin as a chemopreventative drug against prostate cancer in volunteers with the HG-PIN condition.
A total of 60 volunteer subjects participated in a double-blind placebo-controlled study.1 There were 30 men in each group. The men received either a total of 600mg/day of capsules containing a total of 75.7% catechins or a placebo for one year. At the end of the year of treatment 1 tumor was found among those receiving the catechin capsule and 9 tumors were found among the placebo-treated men. No significant side effects or adverse effects were documented. The scientists concluded catechins are safe and effective for preventing pre-malignant lesions from developing into prostate cancer. A secondary observation was that the catechin capsule reduced lower urinary tract symptoms. The treatment may also be used to treat benign prostate hyperplasia symptoms.
Another investigation, a case-control study, was conducted in Hangzhou, southeast China during 2001-2002.2 There were 130 patients with confirmed prostate cancer and 274 control subjects who had no malignant diseases, including prostate cancer and whose ages matched those with prostate cancer. Tea consumption habit data was collected, including how long they have been drinking tea, quantity and frequency of tea consumption. The number of new batches of green tea brewed per day was also collected.
Among the confirmed prostate cancer cases 55% were green tea drinkers compared to nearly 80% of the control subjects. A dose response was also significant, with higher tea consumption correlating with decreasing prostate cancer incidence.
1Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Bettuzzi S, Brausi M, Rizzi F, Castagnetti G, Peracchia G, Corti A. Cancer Res. 2006. 66(2):1234-40.
2 Protective effect of green tea against prostate cancer: a case-control study in southeast China. Jian L, Xie LP, Lee AH, Binns CW. Int J Cancer. 2004. 108(1):130-5.
