Tea and Forearm Blood Flow

Not Applicable

Completed

• Conditions: Vascular Function
• Interventions: Other: Tea; Other: Placebo

• Registration Number: NCT02328339
• Lead Sponsor: Unilever R&D

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

Study Timeline

• Study First Submitted: 2014-12-19
• Study First Submitted QC: 2014-12-30
• Study First Posted: 2014-12-31
• Study Start: 2015-01
• Status Verified: 2015-08
• Primary Completion: 2015-08
• Study Completion: 2015-08
• Last Update Submitted: 2015-08-28
• Last Update Posted: 2015-08-31

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

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)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Black tea	Tea	Approximately 400 mg total polyphenols in 240 ml hot water (loading dose; 2 hours before the start of measurements; t=0) and 130 mg total polyphenols in 120 ml hot water (maintenance dose just before start of the measurements; t=120 min)
Placebo	Placebo	Caramel colour, maltodextrin and tea flavour in 240 ml hot water (2 hours before the start of measurements; t=0) and 120 ml hot water (maintenance dose just before start of the measurements; t=120 min)

Primary Outcome Measures

Name	Time	Method
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 Outcome Measures

Name	Time	Method
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