A recent study has revealed that bottled tea contain fewer polyphenols than a single cup of home-brewed tea.
Researchers have found that many of the increasingly popular beverages included in the study contain fewer polyphenols than a single cup of home-brewed green or black tea.
Some contain such small amounts that consumers would have to drink 20 bottles to get the polyphenols present in one cup of tea.
"Consumers understand very well the concept of the health benefits from drinking tea or consuming other tea products," said Shiming Li of WellGen Inc, who reported on the new study with Chi-Tang Ho 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," said Li.
Li pointed out 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.
Li and colleagues measured the level of polyphenols - a group of natural antioxidants linked to anti-cancer, anti-inflammatory, and anti-diabetic properties - of six brands of tea purchased from supermarkets.
Half of them contained what Li characterized as "virtually no" antioxidants. The rest had small amounts of polyphenols that Li said probably would carry little health benefit, especially when considering the high sugar intake from tea beverages.
"Someone would have to drink bottle after bottle of these teas in some cases to receive health benefits," he said.
The six teas Li analyzed contained 81, 43, 40, 13, 4, and 3 milligrams (mg.) of polyphenols per 16-ounce bottle. One average cup of home-brewed green or black tea, which costs only a few cents, contains 50-150 mg. of polyphenols.
The findings were discussed at the 240th National Meeting of the American Chemical Society (ACS).