A study published in the August issue of Cancer Epidemiology, Biomarkers & Prevention, suggest that Polyphenon E, a green tea concentrate composed of epigallocatechin gallate (EGCG) equivalent to 8-16 cups of green tea, might help some people strengthen their metabolic defense against toxins capable of causing cancer by boosting the production of enzymes which belong to the glutathione S-transferase (GST) family.

Researchers found that use of Polyphenon E enhanced GST activity when data from all participants were included for analysis. But it had its most significant effect in volunteers whose baseline blood measurements showed low GST activity - an 80 percent increase compared to baseline GST activity. Activity did not change in volunteers with medium GST expression, or in those with the highest levels, GST seemed to decrease slightly although researchers believe that decline was due to random variation.

"This is the first clinical study to show proof that chemicals in green tea can increase detoxification enzymes in humans," Chow said. "There may be other mechanism in play by which green tea may protect against cancer development, but this is a good place to start."

Source: American Association for Cancer Research