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Flow Mediated Dilation in Response to Black Tea (T)

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ClinicalTrials.gov Identifier: NCT02273323
Recruitment Status : Completed
First Posted : October 23, 2014
Results First Posted : February 15, 2017
Last Update Posted : February 15, 2017
Sponsor:
Collaborator:
King's College London
Information provided by (Responsible Party):
Unilever R&D

Brief Summary:
Research indicate that people who regularly drink tea have a reduced risk of stroke or heart disease. In a number of studies in which people that normally do not drink showed that their blood vessels function improved when the drunk tea. The current study tests whether a specific black tea improves vessel function in non-tea drinking hypertensive subjects.

Condition or disease Intervention/treatment Phase
Vascular Function Other: Tea Other: Placebo Not Applicable

Detailed Description:
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 in various populations. The current confirmatory study tests a specific black tea against a placebo in a population of in non-tea drinking hypertensive subjects.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Official Title: Flow Mediated Dilation in Response to Consumption of Black Tea Versus Artificial Tea, in Non-tea Drinking Hypertensive Subjects.
Study Start Date : October 2014
Actual Primary Completion Date : October 2015
Actual Study Completion Date : October 2015

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: Tea
Black tea
Other: Tea
Single dose of black tea infusion containing approximately 400 mg flavonoids (expressed as gallic acid equivalents) with added sugar.

Placebo Comparator: Placebo
Placebo
Other: Placebo
Placebo: tea flavour, colouring and sugar




Primary Outcome Measures :
  1. Flow Mediated Dilation [ Time Frame: Before and 2 hours after test product intake ]

    Flow mediated dilation (FMD) of the brachial artery was measured using vascular ultra sound and automated edge detection software:

    • 1 minute baseline scan to measure the baseline diameter of artery
    • 5 minutes of forearm occlusion at 250±30 mmHg, below the elbow (2-5 cm from antecubital crease)
    • 4 minutes FMD scan, which started immediately after release of occlusion Percentage FMD was calculated as the maximum increase in diameter after cuff release relative to the baseline diameter


Secondary Outcome Measures :
  1. Endothelium-independent Vasodilation [ Time Frame: 2.5 hours after test product intake ]
    Endothelium-independent dilation after glyceryl trinitrate defined as maximal percent increase in diameter

  2. Systolic Blood Pressure Supine [ Time Frame: Before and 110 minutes after test product intake ]
    Systolic blood pressure measured while lying down

  3. Diastolic Blood Pressure Supine [ Time Frame: Before and 110 minutes after test product intake ]
    Diastolic blood pressure measured while lying down

  4. Systolic Blood Pressure Sitting [ Time Frame: Before and 90 minutes after test product intake ]
    Systolic blood pressure measured while sitting

  5. Diastolic Blood Pressure Sitting [ Time Frame: Before and 90 minutes after test product intake ]
    Diastolic blood pressure measured while sitting



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Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Males and post menopausal (> 1 year) females, not on hormone replacement therapy
  • Aged >18 and < 65 years
  • Body mass index (BMI) of >=18.0 and =<35.0 kg/m2
  • Hypertension as previously diagnosed by primary care or hospital physician.

    • If untreated, office BP between 140/90 mmHg and 160/100 mmHg on screening
    • If treated, a controlled blood pressure (<160/100) on stable medication for at least 4 weeks

Exclusion Criteria:

  • Tea drinkers: having typically consumed > 1 cup of black tea per week.
  • 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 other than hypertension
  • Clinically significant arrhythmia
  • Diabetes mellitus
  • Chronic Kidney Disease > stage 2
  • 10-year cardiovascular risk equivalent to 20% or greater using the QRisk2 calculator
  • Abnormality of laboratory blood tests considered clinically significant
  • Any other significant intercurrent condition/disease

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02273323


Locations
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United Kingdom
Dept Clinical Pharmacology/CRF, St Thomas Hospital
London, United Kingdom, SE1 7EH
Sponsors and Collaborators
Unilever R&D
King's College London
Investigators
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Principal Investigator: Phillip Chowienczyk, Professor Dept Clinical Pharmacology/CRF, St Thomas Hospital, London UK

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Responsible Party: Unilever R&D
ClinicalTrials.gov Identifier: NCT02273323    
Other Study ID Numbers: REF-BEV-1376
First Posted: October 23, 2014    Key Record Dates
Results First Posted: February 15, 2017
Last Update Posted: February 15, 2017
Last Verified: December 2016
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Keywords provided by Unilever R&D:
Flow mediated dilation
tea
blood pressure
Additional relevant MeSH terms:
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Dilatation, Pathologic
Pathological Conditions, Anatomical