Green Tea Absorption: Extracts are superior to home brewed.
Subject: Green tea extracts are a preferable source of epigallocatechins than either brewed black or green tea.
In many situations, especially in the treatment of cancer, we will suggest high doses of epigallocataechin gallate (EGCG), a chemical found in green tea. The suggested quantities exceed the amount all but the most fanatic patients will be able to obtain from drinking green tea. It would take the equivalent of 15-20 cups of tea a day to come close. We therefore suggest using green tea extracts in capsule form. Based on my assumption that the EGCG in brewed tea might still be more bioavailable, I also suggest drinking a couple of cups of green tea a day in the hope that it will encourage the body to absorb the EGCG better.
It now appears that my assumption is wrong and that the EGCG in brewed tea is less bioavailable than what is in the capsules.
A study published in December, 2004 compared green tea, black tea and green tea extracts. They took 14 healthy men and 16 healthy women who were between 20 and 39 years of age, and randomly assigned them to 3 different sequences of green tea, black tea or green tea extract supplement. More tea flavanols were absorbed from the green tea extracts in capsule form which also increased the antioxidant effect in the blood serum more than the brewed teas. All three treatments provided similar amounts of EGCG. [i]
[i] Am J Clin Nutr. 2004 Dec;80(6):1558-64.
Bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement.
Henning SM, Niu Y, Lee NH, Thames GD, Minutti RR, Wang H, Go VL, Heber D.
Center for Human Nutrition, David Geffen School of Medicine and the Department of Biostatistics, School of Public Health, University of California, Los Angeles, 90095, USA. email@example.com
BACKGROUND: Green and black tea polyphenols have been extensively studied as cancer chemopreventive agents. Many in vitro experiments have supported their strong antioxidant activity. Additional in vivo studies are needed to examine the pharmacokinetic relation of absorption and antioxidant activity of tea polyphenols administered in the form of green or black tea or tea extract supplements. OBJECTIVE: The purpose of this study was to compare the pharmacokinetic disposition of tea polyphenols and their effect on the antioxidant capacity in plasma 8 h after a bolus consumption of either green tea, black tea, or a green tea extract supplement. DESIGN: Thirty healthy subjects were randomly assigned to 3 different sequences of green tea, black tea, or a green tea extract supplement in a 3 x 3 crossover design with a 1-wk washout period in between treatments. RESULTS: Flavanol absorption was enhanced when tea polyphenols were administered as a green tea supplement in capsule form and led to a small but significant increase in plasma antioxidant activity compared with when tea polyphenols were consumed as black tea or green tea. All 3 interventions provided similar amounts of (-)-epigallocatechin-3-gallate. CONCLUSIONS: Our observations suggest that green tea extract supplements retain the beneficial effects of green and black tea and may be used in future chemoprevention studies to provide a large dose of tea polyphenols without the side effects of caffeine associated with green and black tea beverages.
Randomized Controlled Trial
PMID: 15585768 [PubMed - indexed for MEDLINE]