Individuals who drink bottled teas in hopes of reaping the many health benefits of the powerful antioxidants known to be present in them may want to try brewing their own beverages instead. Researchers say tests show that many bottled teas are lacking when it comes to antioxidants, or polyphenols.

Scientists with a New Jersey biotech company 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.

The beverages they analyzed contained 81, 43, 40, 13, 4, and 3 milligrams of polyphenols per 16-ounce bottle. Researchers say the readings compare to 50-150 milligrams of polyphenols found in one average cup of home-brewed green or black tea.

"There is a huge gap between the perception that tea consumption is healthy and the actual amount of the healthful nutrients found in bottled tea beverages," said lead researcher Shiming Li, Ph.D. "Our analysis of tea beverages found that the polyphenol content is extremely low. Someone would have to drink bottle after bottle of these teas in some cases to receive health benefits."