A green tea extract may pack a stronger antioxidant punch than the beverage itself does, new research suggests.

The findings, say the study authors, indicate that a capsule can retain the benefits of tea, without the caffeine.

Green tea extract could therefore be used in clinical trials looking at whether large doses of tea antioxidants can lower the risk of certain cancers, the researchers report in the American Journal of Clinical Nutrition.

A number of studies have suggested that green tea may have health benefits that include a lower risk of heart disease and certain cancers. Researchers suspect the explanation may lie in plant compounds called flavonoids, which are found in tea, wine, and a variety of fruits and vegetables. Flavonoids act as antioxidants, which means they help counter the potentially cell-damaging effects of substances found in the body called oxygen free radicals.

For the new study, Dr. Susanne M. Henning and her colleagues at the University of California, Los Angeles, tested 30 volunteers’ absorption of antioxidants from a single, large dose of green tea, black tea or green tea extract in the form of a capsule.

Every participant was given each of the teas and the extract, on three separate occasions. After drinking the tea or taking the capsule, the men and women gave several blood samples over the following 8 hours.

Henning and her colleagues found that while volunteers consumed equal antioxidant doses from the teas and the extract, the latter got more of the antioxidants into their blood.

The findings, according to the researchers, suggest that antioxidants from green tea extract are more easily absorbed, and lead to a “small but significant increase” in antioxidant activity in the blood.

“Our findings,” Henning’s team concludes, “suggest that green tea extract supplements retain the beneficial effects of green and black tea.”

These extracts, they add, could be used in future cancer-prevention research to provide large antioxidant doses without the side effects of caffeine.

SOURCE: American Journal of Clinical Nutrition, December 2005.