Celebrated for a range of health benefits, polyphenols have been linked to a preventive role for the main chronic diseases such as cardiovascular, cancer, and all inflammatory diseases. The majority of specialists agree that a high consumption of polyphenols can decrease and prevent all these diseases.
But new evidence suggests that consumers of bottled tea drinks may end up getting fewer polyphenols than they bargained for. At the 240th meeting of the ASC in Boston, Shiming Li, a chemist from the biotech firm WellGen presented research on polyphenol content in both brewed and bottled tea.
Significant differences
Comparing six bottled teas, Li found some significant differences in the amount of antioxidants present. Per 16-ounce bottles, the researcher said the teas contained 81, 43, 40, 13, 4 and 3 milligrams (mg) of polyphenols. Meanwhile, an average cup of green or black tea contains between 50 and 150 mg.
Commenting on the low levels found in some products, Li said: “Someone would have to drink bottle after of bottle… to receive health benefits. I was surprised at the low polyphenol content. I didn’t expect to see such a low level.”
Explanatory factors
One reason for the low amounts could ultimately be consumer taste buds. Li continued: “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. The simplest way is to add less tea, which makes the tea polyphenol content low but tastes smoother and sweeter.”
But Li added that there are other factors that may influence polyphenol content including processing methods and the stability of the antioxidants once packaged
To measure the polyphenol levels in the tea products Li, working with Professor Chi-Tang Ho and colleagues, used a technique called high-performance liquid chromatography (HPLC).
The scientists plan to publish the research in a journal and hope to do so in the fourth quarter of the year.