BIOAVAILABILITY OF CATECHINS FROM TEA - THE EFFECT OF MILK

Objectives: To assess the blood concentration of catechins following g reen or black tea ingestion and the effect of addition of milk to blac k tea. Design: Twelve volunteers received a single dose of green tea, black tea and black tea with milk in a randomized cross-over design wi th one-week intervals. Blood samples were drawn before and up to eight hours after tea consumption. Setting: The study was performed at the Unilever Research Vlaardingen in The Netherlands. Subjects: Twelve hea lthy adult volunteers (7 females, 5 males) participated in the study. They were recruited among employees of Unilever Research Vlaardingen. Interventions: Green tea, black tea and black tea with semi-skimmed mi lk (3 g tea solids each). Results: Consumption of green tea (0.9 g tot al catechins) or black tea (0.3 g total catechins) resulted ina rapid increase of catechin levels in blood with an average maximum change fr om baseline (CVM) of 0.46 mu mol/l (13%) after ingestion of green tea and 0.10 mu mol/l (13%) in case of black tea. These maximum changes we re reached after (mean (s.e.m.)) t = 2.3 h (0.2) and t = 2.2 h (0.2) f or green and black tea respectively. Blood levels rapidly declined wit h an elimination rate (mean (CVM)) of t(1/2) = 4.8 h (5%) for green te a and t(1/2) = 6.9 h (8%) for black tea. Addition of milk to black tea (100 ml in 600 ml) did not significantly affect the blood catechin le vels (areas under the curves (mean (CVM) of 0.53 h. mu mol/l (11%) vs 0.60 h. mu mol/l (9%) for black tea and black tea with milk respective ly. Conclusion: Catechins from green tea and black tea are rapidly abs orbed and milk does not impair the bioavailability of tea catechins.