A single dose of tea with or without milk increased plasma antioxidant activity in humans European Journal of Clinical Nutrition, 2000; 54: Leenen et al.

Purpose of Study To investigate the effect of black and green tea consumption, with and without milk, on plasma antioxidant activity.

Methods: study participants N=21 Non-smokers Stable body weight No medication No dietary supplements containing vitamin C, E, carotenoids, calcium or iron

Methods: experimental design RCT Treatments included the following –300 ml black tea –300 ml green tea –240 ml black tea + 60 ml milk –240 ml green tea + 60 ml milk

Methods: Analytical Procedure Plasma antioxidant activity was measured using FRAP, blood samples were taken at 30, 60, 90, 120 minutes. Total catechins in plasma were analyzed using HPLC.

Statistical Analysis Effects of tea and addition of milk to tea were evaluated by ANOVA; two sided P values were statisticaly significant at P <0.05.

Results of the Study Consumption of black tea resulted in an increase in plasma FRAP activity. Consumption of green tea resulted in an even higher plasma FRAP activity than black tea. Addition of milk to either black or green tea did not significantly alter FRAP activity. Consumption of black or green tea resutled in an increase of catechins in plasma, but were higher in green tea.

Conclusion Consumption of a single dose of black or green tea induces a significant rise in plasma antioxidant activity in vivo with higher response attributed to green tea.