Clinical trial NCT02328339: Tea and Forearm Blood Flow
Official title: Forearm Blood Flow Response to Acute Consumption of Black Tea
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Vascular Function
Lead sponsor: Unilever R&D
Sponsor class: INDUSTRY
Collaborators: name: Radboud University Medical Center
First posted: 2014-12-31
Enrollment: 20
Sex: ALL
Minimum age (years): 45
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

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

Eligibility criteria: 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)

Primary outcomes:
measure: Forearm blood flow response to acetylcholine
timeFrame: During acetylcholine infusion 120-140 min after first tea/placebo intake
Secondary outcomes:
measure: Forearm blood flow response to sodium nitropusside
timeFrame: During sodium nitropusside infusion 170-190 min after first tea/placebo intake
measure: Forearm blood flow response to L-NMMA
timeFrame: During L-NMMA infusion 220-240 min after first tea/placebo intake
Other outcomes:
Locations:
Study officials:
affiliation: Radboud University Medical Center
name: Sean Roerink, Dr.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Greyling A, Wolters TLC, de Bresser DM, Roerink SHPP, Riksen NP, Mulder TP, Rowson MJ, Hopman MT, Thijssen DHJ. The acute effect of black tea consumption on resistance artery endothelial function in healthy subjects. A randomized controlled trial. Clin Nutr ESPEN. 2018 Feb;23:41-47. doi: 10.1016/j.clnesp.2017.10.011. Epub 2017 Nov 8.