"Strongest" Antioxidant Found in Tea

NEW YORK (Reuters) -- Anyone for a steaming hot cup of antioxidants? One expert says tea leaves contain the strongest known form of the disease-fighting compounds.

"Our research shows that green tea contains a powerful antioxidant, known as epigallocatechin gallate, or EGCG," said Dr. Lester Mitscher, distinguished professor of medicinal chemistry at the University of Kansas in Lawrence, Kansas. EGCG is the "strongest of all" the antioxidants he's aware of -- more than 100 times as effective at soaking up free radicals than vitamin C, and 25 times more powerful than vitamin E.

Antioxidants are thought to help prevent the development of certain diseases, especially cancers. They may do this by 'mopping-up' free radicals -- byproducts of the body's metabolic processes. Left alone, free radicals can cause damage to cellular DNA, which may in turn trigger disease.  

Mitscher put various teas -- green, black, and oolong -- through tests designed to spot the presence of antioxidants. Green teas have, by far, the highest concentrations of active EGCG, Mitscher said. "Green tea is plucked at the appropriate time and then is immediately steamed," he explained. "That heat process prevents the internal oxidation of these compounds."

He said oolong and black tea leaves are allowed to oxidize during processing. This oxidization greatly reduces the amount of active EGCG in those teas. Black tea, for example contains just 40% of the EGCG of green tea.

The daily tea consumption needed for optimum antioxidant effects has "not really been firmly established," Mitscher said. But he points out that in countries like China and Japan, "people customarily drink 4 or more cups (of green tea) per day." Studies in those populations reveal "a lower incidence of ...degenerative diseases," he said. "That's probably a healthy dose. We don't know that one cup (per day) wouldn't work, but that's really not been established."

Mitscher presented his findings this week at the American Chemical Society national meeting in Las Vegas. His study was funded by a grant from Pharmanex, a company which produces plant-based health care products.