Drinking green tea may play a role in the inhibition of prostate cancer tumor growth, according to a study presented at the American Association for Cancer Research’s International Conference on Frontiers in Cancer Prevention Research in Anaheim, Calif.

Susanne M. Henning, PhD, RD, of the David Geffen School of Medicine at the University of California-Los Angeles, and colleagues conducted a phase 2 intervention study in which they randomized men to either six cups of brewed green tea (34 men) or water (33 men) daily for three to eight weeks before prostatectomy. The prostate concentration of green tea polyphenols (GTPs) and their metabolites was measured using high-performance liquid chromatography.

The researchers found that, while no change was seen in the control group, the serum PSA level was significantly decreased in the tea group compared with baseline. PSA protein expression in prostate tissue was nonsignificantly lower in men consuming tea. In 31 of 34 men consuming tea, bioactive GTPs were detected in prostate tissue, but these were not seen in tissues from the control group. For men in the green tea group, there was a significant decrease in intranuclear, but not cytoplasmic, NFκB staining, compared to tumors from the control group. There was a significant increase in the ratio of cytoplasmic staining of pro-apoptotic Bax to Bcl-2, but no change in cytoplasmic Bcl2 and Bax staining.

“This research offers new insights into the mechanisms by which green tea consumption may reduce the risk for prostate cancer by opposing processes such as inflammation, which are associated with prostate cancer growth,” Dr. Henning said in a statement.