Effect of Black Tea on Vascular Function (Heraclitus)

Randomized Double Blind Placebo Controlled Crossover Study to Assess the Effect of Black Tea on Flow-Mediated Dilation in Healthy, Non-tea Drinking Males

Epidemiological studies indicate that regular consumption of three cups of black tea per day reduces the risk of stroke or myocardial infarction. In a number of previous nutrition intervention studies tea has been shown to improve vascular function as assessed by Flow Mediated Dilation (FMD).

Study Overview

• Status: Completed
• Conditions: Vascular Function
• Intervention / Treatment: Other: Placebo; Other: Black tea extract; Other: Positive control

Detailed Description

The current study tests a specific Black tea extract against a placebo in population that has previously show to be sensitive to the effect of black tea on Flow Mediated dilation. A tea extract that has previously been shown to improve FMD is included as the positive control.

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Pisa, Italy
    • Azienda Ospedaliero-Universitaria Pisana, Centro di Farmacologia Clinicaper la Sperimentazione dei Farmaci

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 65 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Apparently healthy male volunteers with no history of cardiovascular disease
• Having body mass index (BMI) of between 18.0 and 30.0 kg/m2 (inclusive)
• Non-smokers (> 2 years)
• Non-tea drinkers (less or equal 1 cup/week)
• Limited alcohol intake (less or equal 21 units/week)
• Systolic blood pressure less or equal 160 mmHg and/or diastolic blood pressure less or equal 100 mmHg at screening
• Brachial artery can be imaged using ultrasound and at screening FMD value is within the expected range as judged by the PI
• 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).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: QUADRUPLE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Black tea extract; Spray dried aqueous extract of a representative batch of black tea	Other: Black tea extract; Black tea extract
ACTIVE_COMPARATOR: Positive control; Spray dried aqueous extract of a batch of tea extract that has shown to improve FMD previously	Other: Positive control; Positive control
PLACEBO_COMPARATOR: Placebo; Food grade colouring, artificial tea flavour and an amount of caffeine matched to the caffeine in the Black tea extract	Other: Placebo; Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Flow Mediated Dilation, Acute-upon-chronic, Black Tea	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 8.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Flow Mediated Dilation, Acute, Black Tea	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 1
Flow Mediated Dilation, Chronic, Black Tea	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption day 1 to before consumption day 8.
Flow Mediated Dilation, Acute-upon-chronic, Positive Control	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 8
Flow Mediated Dilation, Acute, Positive Control	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 1
Flow Mediated Dilation, Chronic, Positive Control	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to before consumption day 8

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systolic Blood Pressure, Black Tea	Change in Systolic blood pressure	From before consumption on day 1 to before consumption on day 8
Diastolic Blood Pressure Black Tea	Change in Diastolic blood pressure	From before consumption on day 1 to before consumption day 8
Systolic Blood Pressure, Positive Control	Change in systolic blood pressure	From before consumption (baseline) day 1 to before consumption day 8
Diastolic Blood Pressure, Positive Control	Change in Diastolic Blood pressure	From before consumption on day 1 to before consumption day 8
Endothelium Independent Dilation, Acute-upon-chronic, Black Tea	FMD measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 8
Endothelium Independent Dilation, Chronic, Black Tea	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to before consumption day 8
Endothelium-Independent Dilation, Acute, Black Tea	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 1
Endothelium Independent Dilation, Acute-upon-chronic, Positive Control	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 8
Endothelium Independent Dilation, Chronic, Positive Control	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to before consumption day 8
Endothelium Independent Dilation, Acute, Positive Control	Flow mediated dilation (FMD) measurement included the following steps: 1 minute base scan to measure the baseline diameter of artery (Resting stage); 5 minutes of forearm occlusion at 300±30 mmHg (cuff occlusion stage), just below the elbow 2-5 cm from antecubital crease); 4 minutes FMD scan, which started immediately after release of occlusion (reactive hyperaemia stage); When the artery had returned to baseline a second 1 minute scan was taken; 25 µg sublingual glyceryl trinitrate (GTN) was given to the subject; 5 minutes GTN scan to assess the endothelium-independent dilation FMD and response to GTN was calculated as maximal percent increase in diameter above baseline (mean value of measures obtained during 1 minute before cuff inflation).	From before consumption on day 1 to 2 hours post consumption on day 1

Collaborators and Investigators

• Sponsor: Unilever R&D
• Collaborators: Sprim Advanced Life Sciences
• Investigators: Principal Investigator: Lorenzo Ghiadoni, MD, University of Pisa, Internal medicine

Study record dates

Study Major Dates

• Study Start: September 1, 2013
• Primary Completion (ACTUAL): November 1, 2013
• Study Completion (ACTUAL): December 1, 2013

Study Registration Dates

• First Submitted: September 8, 2013
• First Submitted That Met QC Criteria: September 16, 2013
• First Posted (ESTIMATE): September 19, 2013

Study Record Updates

• Last Update Posted (ACTUAL): March 22, 2017
• Last Update Submitted That Met QC Criteria: February 17, 2017
• Last Verified: February 1, 2017

More Information

Terms related to this study

• Keywords: Vascular function; Tea; Flow mediated dilation
• Other Study ID Numbers: REF-BEV-1134