Study: R.-T.-D. teas low in antioxidants
August 23, 2010
by Keith Nunes
BOSTON — The amounts of antioxidants, or polyphenols, in bottled, ready-to-drink teas may be less than in home-brewed teas, according to a study presented at the 240th National Meeting of the American Chemical Society, being held this week in Boston.
“Consumers understand very well the concept of the health benefits from drinking tea or consuming other tea products,” said Shiming Li, a senior scientist at WellGen, Inc., who reported on the new study with Professor Chi-Tang Ho, a professor in the department of food science at Rutgers, and his colleagues. “However, there is a huge gap between the perception that tea consumption is healthy and the actual amount of the healthful nutrients — polyphenols — found in bottled tea beverages. Our analysis of tea beverages found that the polyphenol content is extremely low.”
Dr. Li and colleagues measured the level of polyphenols in six brands of tea purchased from supermarkets. Half of them contained what he characterized as “virtually no” antioxidants. The rest had small amounts of polyphenols that Dr. Li said probably would carry little health benefit.
Dr. Li said that in addition to the low polyphenol content, bottled commercial tea contains other substances, including large amounts of sugar and the accompanying calories that health-conscious consumers may be trying to avoid.
“Someone would have to drink bottle after bottle of these teas in some cases to receive health benefits,” he said. “I was surprised at the low polyphenol content. I didn’t expect it to be at such a low level.”
The six teas Dr. Li analyzed contained 81, 43, 40, 13, 4, and 3 mg of polyphenols per 16-oz bottle. One average cup of home-brewed green or black tea contains 50 to 150 mg of polyphenols.
He used a laboratory technique termed high-performance liquid chromatography to make the measurements of polyphenols in bottled tea beverages.