Vascular Function
Conditions
Brief summary
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.
Detailed description
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
Interventions
OTHERTea
Black tea infusion equivalent to approximately 530 mg total polyphenols expressed as gallic acid equivalents
OTHERPlacebo
Placebo matched to tea with respect to taste and appearance
Sponsors
Unilever R&D
Radboud University Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
45 Years to 75 Years
Healthy volunteers
Yes
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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Forearm blood flow response to acetylcholine | During acetylcholine infusion 120-140 min after first tea/placebo intake | Does tea ingestion change mean forearm blood flow response to acetylcholine when compared to placebo |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Forearm blood flow response to sodium nitropusside | During sodium nitropusside infusion 170-190 min after first tea/placebo intake | Does tea ingestion change mean forearm blood flow response to sodium nitropusside when compared to placebo |
| Forearm blood flow response to L-NMMA | During L-NMMA infusion 220-240 min after first tea/placebo intake | Does tea ingestion change mean forearm blood flow response to L-NG-monomethyl Arginine (L-NMMA) when compared to placebo |
Outcome results
None listed