Tea and Forearm Blood Flow

Forearm Blood Flow Response to Acute Consumption of Black Tea

The study will explore the benefit of tea for microcirculation. Subjects will consume tea ar a placebo matched for taste and appearance in a blinded cross over design.

Epidemiological studies indicate that regular consumption of black tea reduces the risk of cardiovascular diseases. Tea consumption can result in improvements in endothelial function of conduit arteries as measured by flow mediated dilation.

Less is known however about its effects in other vascular beds. The study will test the hypothesis that tea affects endothelial function in the muscle microcirculation. This will be done by assessment of forearm blood flow using venous occlusion plethysmography after consumption of black tea against or placebo in a randomised, full cross-over study in 20 healthy middle-aged to elderly subjects

Inclusion Criteria:

• Males and post menopausal (> 1 years) females
• Aged ≥ 45 and ≤ 75 years
• Body mass index (BMI) of ≥ 18.0 and ≤ 35.0 kg/m2
• 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).
• Normal blood coagulation as assessed by routine lab tests

Exclusion Criteria:

• Strenuous exercise > 2 hours per week. Strenuous exercise is defined as exercise which induces sweating and causes sufficient breathlessness to limit conversation
• Current smoker or has stopped smoking less than 6 months before start of study
• Self reported alcohol intake of > 21 units/week)
• Established cardiovascular disease or clinically significant arrhythmia
• Diabetes mellitus
• Blood pressure > 160/100 mmHg
• Taking medication that might affect endothelial function (as judged by the PI)