NCT01945970 - Effect of Black Tea on Vascular Function | Crick

Overview

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).

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

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

QUADRUPLE

Enrollment

30

Conditions

Vascular Function

Interventions

Black tea extractOTHER

Black tea extract

Positive controlOTHER

Positive control

PlaceboOTHER

Placebo

Eligibility

Sex: MALEMin age: 40 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

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).

Locations (1)

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

Pisa, Italy

Outcomes

Primary Outcomes

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).

Time frame: From before consumption on day 1 to 2 hours post consumption on day 8.

Secondary Outcomes

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).

Time frame: 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).