The effect of black tea on risk factors of cardiovascular disease in a normal population

Objectives. A prospective randomized controlled clinical trial determined the effect of Mauritian black tea consumption on fasting blood plasma levels of glucose, lipid profiles and antioxidant status in a normal population. Methods. The study group (71%) consumed 3 x 200 ml of black tea infusate/day for 12 weeks without additives followed by a 3 week wash-out. The control group (29%) consumed equivalent volume of hot water for same intervention period. Results. The tea used had high levels of gallic acid derivatives (50 +/- 0.4 mg/L), flavan-3-ols (42 +/- 2 mg/L), flavonols (32 +/- 1 mg/L) and theaflavins (90 +/- 1 mg/L). Daily 9 g supplementation of black tea infusate induced, in a normal population, a highly significant decrease of fasting serum glucose (18.4%; p<0.001) and triglyceride levels (35.8%; p<0.01), a significant decrease in LDL/HDL plasma cholesterol ratio (16.6%; p<0.05) and a non significant increase in HDL plasma cholesterol levels (20.3%), while a highly significant rise in plasma antioxidant propensity (FRAP: 418%; p<0.001) was noted. Conclusion. Black tea consumed within a normal diet contributes to a decrease of independent cardiovascular risk factors and improves the overall antioxidant status in humans. (C) 2011 Elsevier Inc. All rights reserved.