Bottled tea may contain no antioxidants
Aug-24-2010

Drinking green or black tea offers a range of health benefits. But drinking bottled tea may give the drinkers little benefits as researchers from Wellgen - a biotechnology company based out of North Brunswick, New Jersey found many bottled teas contain almost no antioxidants- polyphenols from tea.

Dr. Shiming Li, an anlytical and natural products chemist, reported at the 240th National Meeting of the American Chemical Society that many bottled tea beverages contain much fewer polyphenols than a single cup of home-brewed green or black tea and some contain almost no polyphenols or only about 5 percent of polyphenols found in one cup of home brewed black tea or green tea.

Using a technique called high performance liquid chromatography, Dr. Li along with Professor Chi-Tang Ho, specializing in natural products and flavor chemistry, at Rutgers University, analyzed polyphenols in six brands of bottled teas from the market and found they contained 81, 43, 40, 13, 4 and 3 milligrams of polyphenols per 16-ounce bottle. In comparison, one cup of home-brewed tea contain 50 to 150 milligram of polyphenols.

Bottled tea products not only lack sufficient amounts of antioxidants - polyphenols, but also contain high amounts of sugar, which is considered unhealthy, Dr. Li was cited as saying.

Dr. Li said some bottled tea manufacturers do label the amount of tea polyphenols on the packaging, but often the nutrition facts are not accurate. There is no industrial standard or governmental guidelines that can guarantee the accuracy of any claim.

"Polyphenols are bitter and astringent, but to target as many consumers as they can, manufacturers want to keep the bitterness and astringency at a minimum," Li explained. "The simplest way is to add less tea, which makes the tea polyphenol content low but tastes smoother and sweeter."

Polyphenols in teas, particularly green tea have been found protective against a range of diseases including cancer, inflammation, diabetes, heart disease. Rutgers University researchers such as Dr. C.S. Yang have found that green tea polyphenols like Epigallocatechin gallate (EGCG) protect against cancer by promoting apoptosis.

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