Effect of Black Tea on Vascular Function

Randomized Double Blind Placebo Controlled Crossover Study to Assess the Effect of Black Tea on Flow-Mediated Dilation in Healthy, Non-tea Drinking Males

Epidemiological studies indicate that regular consumption of three cups of black tea per day reduces the risk of stroke or myocardial infarction. In a number of previous nutrition intervention studies tea has been shown to improve vascular function as assessed by Flow Mediated Dilation (FMD).

The current study tests a specific Black tea extract against a placebo in population that has previously show to be sensitive to the effect of black tea on Flow Mediated dilation. A tea extract that has previously been shown to improve FMD is included as the positive control.

Inclusion Criteria:

• Apparently healthy male volunteers with no history of cardiovascular disease
• Having body mass index (BMI) of between 18.0 and 30.0 kg/m2 (inclusive)
• Non-smokers (> 2 years)
• Non-tea drinkers (less or equal 1 cup/week)
• Limited alcohol intake (less or equal 21 units/week)
• Systolic blood pressure less or equal 160 mmHg and/or diastolic blood pressure less or equal 100 mmHg at screening
• Brachial artery can be imaged using ultrasound and at screening FMD value is within the expected range as judged by the PI
• Judged to be in good health on the basis of medical history, physical examination and routine laboratory tests (total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, glucose, highly sensitive C-reactive protein).