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Completed

NCT Number: NCT01945970

Effect of Black Tea on Vascular Function

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).

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Key information

Conditions

Vascular Function

Age range

40 year–65 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

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

Pisa, Italy

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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).

Treatment and study plan

Black tea extract

Other

Black tea extract

Positive Control

Other

Positive control

Placebo

Other

Placebo

Primary outcomes

  1. Flow Mediated Dilation, Acute-upon-chronic, Black Tea

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

    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).

Secondary outcomes

  1. Flow Mediated Dilation, Acute, Black Tea

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

    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).

  2. Flow Mediated Dilation, Chronic, Black Tea

    Time frame: From before consumption day 1 to before consumption day 8.

    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).

  3. Flow Mediated Dilation, Acute-upon-chronic, Positive Control

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

    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).

  4. Flow Mediated Dilation, Acute, Positive Control

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

    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).

  5. Flow Mediated Dilation, Chronic, Positive Control

    Time frame: From before consumption on day 1 to before consumption day 8

    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).

Other outcomes

  1. Systolic Blood Pressure, Black Tea

    Time frame: From before consumption on day 1 to before consumption on day 8

    Change in Systolic blood pressure

  2. Diastolic Blood Pressure Black Tea

    Time frame: From before consumption on day 1 to before consumption day 8

    Change in Diastolic blood pressure

  3. Systolic Blood Pressure, Positive Control

    Time frame: From before consumption (baseline) day 1 to before consumption day 8

    Change in systolic blood pressure

  4. Diastolic Blood Pressure, Positive Control

    Time frame: From before consumption on day 1 to before consumption day 8

    Change in Diastolic Blood pressure

  5. Endothelium Independent Dilation, Acute-upon-chronic, Black Tea

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

    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).

  6. Endothelium Independent Dilation, Chronic, Black Tea

    Time frame: From before consumption on day 1 to before consumption day 8

    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).

  7. Endothelium-Independent Dilation, Acute, Black Tea

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

    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).

  8. Endothelium Independent Dilation, Acute-upon-chronic, Positive Control

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

    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).

  9. Endothelium Independent Dilation, Chronic, Positive Control

    Time frame: From before consumption on day 1 to before consumption day 8

    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).

  10. Endothelium Independent Dilation, Acute, Positive Control

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

    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).

Sponsors and collaborators

Lead sponsor

Unilever R&D

Industry

Collaborators

  • Sprim Advanced Life Sciences

Registry information

Official study title

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

Acronym: Heraclitus

Important dates

Study start
2013
Primary completion
2013
Study completion
2013
First posted
Sep 19, 2013
Registry last updated
Mar 22, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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