has become one the most popular health foods mainly because of the flavanols it contains. Both green tea
and black tea contain
, the most widely studied being
. Studies suggest the health promoting effects of EGCG
are to a large extent mediated by its antioxidant properties. One question that has not been addressed is whether
supplements that contain tea extracts have the same bioavailability as the tea consumed as a liquid. This study compared
the bioavailability of three types of tea: green tea, black tea, and a supplement containing green tea extract.
The green and black tea were prepared with boiling water and allowed to steep for 5 minutes and the supplement was
consumed as capsules. All 3 teas had the same EGCG content. Flavanol absorption was greatest with the supplement in
capsule form compared to the green and black tea. The green tea supplement
also resulted in greater blood antioxidant
activity. The study suggests that
green tea supplements
are more bioavailable than green tea or black tea.
Henning SM, Niu Y, Lee NH, Thames GD, Minutti RR, Wang H, Go VL, Heber D. Bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement. Am J Clin Nutr. 2004 Dec;80(6):1558-64.