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.

Study Overview

• Status: Completed
• Conditions: Vascular Function
• Intervention / Treatment: Other: Tea; Other: Placebo

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 Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 45 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Black 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)	Other: Tea; Black tea infusion equivalent to approximately 530 mg total polyphenols expressed as gallic acid equivalents
Placebo Comparator: 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)	Other: Placebo; Placebo matched to tea with respect to taste and appearance

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Forearm blood flow response to acetylcholine	Does tea ingestion change mean forearm blood flow response to acetylcholine when compared to placebo	During acetylcholine infusion 120-140 min after first tea/placebo intake

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Forearm blood flow response to sodium nitropusside	Does tea ingestion change mean forearm blood flow response to sodium nitropusside when compared to placebo	During sodium nitropusside infusion 170-190 min after first tea/placebo intake
Forearm blood flow response to L-NMMA	Does tea ingestion change mean forearm blood flow response to L-NG-monomethyl Arginine (L-NMMA) when compared to placebo	During L-NMMA infusion 220-240 min after first tea/placebo intake

Collaborators and Investigators

• Sponsor: Unilever R&D
• Collaborators: Radboud University Medical Center
• Investigators: Principal Investigator: Sean Roerink, Dr., Radboud University Medical Center

Publications and helpful links

General Publications

• 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.

Study record dates

Study Major Dates

• Study Start: January 1, 2015
• Primary Completion (Actual): August 1, 2015
• Study Completion (Actual): August 1, 2015

Study Registration Dates

• First Submitted: December 19, 2014
• First Submitted That Met QC Criteria: December 30, 2014
• First Posted (Estimate): December 31, 2014

Study Record Updates

• Last Update Posted (Estimate): August 31, 2015
• Last Update Submitted That Met QC Criteria: August 28, 2015
• Last Verified: August 1, 2015

More Information

Terms related to this study

• Other Study ID Numbers: REF-BEV-1797

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No