On the positive side, green tea is cheap, widely available, and has low toxicity. Now, we just need some good studies of efficacy.

Writing in the Mayo Clinic Proceedings, 5 researchers summarized what we know so far.

On the positive side, derivatives of green tea — particularly (-)-epigallocatechin-3-gallate (EGCG) — appear to have the following anticarcinogenic properties.

• An antioxidant: prevents oxidative damage in healthy cells
• An antiangiogenic agent: prevents tumors from developing a blood supply needed to grow larger
• Stimulator of apoptosis (cell death): negatively regulates the cell cycle to prevent it from multiplying
• Antibacterial activity: might be important to prevent gastric cancer

However?
Although some epidemiological studies suggest that green tea compounds could protect against cancer, the findings are inconsistent. And poor study design makes it difficult to generalize these observations to other groups of patients.

The bottom line?
The authors believe that further evaluation of EGCG is warranted. The focus should be on how the active ingredients in green tea interact with environmental and genetic factors, and clarification of the mechanism by which EGCG affects different cancer types.

6/15/07 12:58 JR