Effect of Blueberries on Vascular Function in Healthy Men

NCT ID: NCT01292954

Last Updated: 2011-02-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

10 participants

Study Classification

INTERVENTIONAL

Study Start Date

2010-10-31

Study Completion Date

2011-02-28

Brief Summary

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Scientific question to be addressed: To determine the effects of acute blueberry ingestion on vascular function and blood pressure in humans

Hypothesis: Acute consumption of blueberry induces an improvement in blood pressure and vascular function through the impact of blueberry flavonoids on the vascular system.

Study objectives: To determine the dose-dependency of a blueberry drink on blood pressure and vascular function in healthy subjects and to determine pharmacokinetics of blueberry polyphenols

Detailed Description

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Coronary heart disease (CHD) remains one of the major causes of premature death in the world. There is now substantial evidence to indicate that the cells lining the inner surface of arteries play a major role in protection against the development and progression of CHD. This layer of cells is termed the endothelium and regulates vascular tone by promoting the expansion and contraction of the blood vessel. There are a variety of non-invasive techniques for measuring endothelial function.

Research provides evidence that consumption of a diet high in plant foods and rich in polyphenols is associated with a reduction in incidence of coronary heart disease (CHD). Polyphenols, of which the flavonoids are the largest group, are thought to play a role in the reduction of incidence of chronic diseases such as cardiovascular disease and stroke. Recent studies in humans show that flavonoid-rich foods improve peripheral blood flow and surrogate markers of cardiovascular function. These effects were associated with acute elevations in the levels of circulating nitric oxide species, an enhanced flow mediated dilatation (FMD) response of conduit arteries, and an augmented microcirculation. Increases in circulating nitric oxide species in response to flavonoid ingestion suggest that circulating flavonoids (and/or their metabolic forms) may exert positive effects on vascular tone.

The purpose of this study is to assess the impact of acute flavonoid intake on postprandial vascular reactivity of healthy volunteers. Specifically, the investigators plan to perform a randomised, double blind, cross-over human intervention trial using a blueberry drink to investigate the dose-dependent effects of blueberries using a range of techniques to measure endothelial function. The study will not only measure the acute effects of flavonoid ingestion on vascular reactivity but will also assess flavonoid and metabolite levels in blood and urine and other endothelial markers.

Conditions

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Healthy

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

TRIPLE

Participants Investigators Outcome Assessors

Study Groups

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Low dose blueberry

Group Type ACTIVE_COMPARATOR

Blueberries

Intervention Type DIETARY_SUPPLEMENT

low dose: 31.4 g of freeze dried blueberry reconstituted in water medium dose: 57 g of freeze dried blueberry reconstituted in water high dose: 80 g of freeze dried blueberry reconstituted in water Placebo: sugars and vitamin c match control in water Frequency:1 single time Total Duration: 3 days study over 3 weeks period

medium dose blueberry

Group Type ACTIVE_COMPARATOR

Blueberries

Intervention Type DIETARY_SUPPLEMENT

low dose: 31.4 g of freeze dried blueberry reconstituted in water medium dose: 57 g of freeze dried blueberry reconstituted in water high dose: 80 g of freeze dried blueberry reconstituted in water Placebo: sugars and vitamin c match control in water Frequency:1 single time Total Duration: 3 days study over 3 weeks period

high dose blueberry

Group Type ACTIVE_COMPARATOR

Blueberries

Intervention Type DIETARY_SUPPLEMENT

low dose: 31.4 g of freeze dried blueberry reconstituted in water medium dose: 57 g of freeze dried blueberry reconstituted in water high dose: 80 g of freeze dried blueberry reconstituted in water Placebo: sugars and vitamin c match control in water Frequency:1 single time Total Duration: 3 days study over 3 weeks period

control

Group Type PLACEBO_COMPARATOR

Blueberries

Intervention Type DIETARY_SUPPLEMENT

low dose: 31.4 g of freeze dried blueberry reconstituted in water medium dose: 57 g of freeze dried blueberry reconstituted in water high dose: 80 g of freeze dried blueberry reconstituted in water Placebo: sugars and vitamin c match control in water Frequency:1 single time Total Duration: 3 days study over 3 weeks period

Interventions

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Blueberries

low dose: 31.4 g of freeze dried blueberry reconstituted in water medium dose: 57 g of freeze dried blueberry reconstituted in water high dose: 80 g of freeze dried blueberry reconstituted in water Placebo: sugars and vitamin c match control in water Frequency:1 single time Total Duration: 3 days study over 3 weeks period

Intervention Type DIETARY_SUPPLEMENT

Eligibility Criteria

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Inclusion Criteria

* Male
* A signed consent form
* Age 19-40 years old
* Body mass index - 18.5-30 kg/m2

Exclusion Criteria

* Blood pressure \> 150/90 mmHg
* Haemoglobin (anaemia marker) \< 125 g/l
* Gamma GT (liver enzymes) \> 80 IU/l
* Cholesterol \> 6.5 mmol/l
* Had suffered a myocardial infarction or stroke in the previous 12 months
* Suffers from any reproductive disorder
* Suffers from any blood-clotting disorder
* Suffers from any metabolic disorders (e.g. diabetes or any other endocrine or liver diseases)
* Any dietary restrictions or on a weight reducing diet
* Drinking more than 21 units per week
* On any medication affecting blood clotting
* On any vitamin supplements/fish oil capsules
* Smoking
* Vegetarians or vegans
Minimum Eligible Age

19 Years

Maximum Eligible Age

40 Years

Eligible Sex

MALE

Accepts Healthy Volunteers

Yes

Sponsors

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Alpro Foundation

OTHER

Sponsor Role collaborator

Wild Blueberry Association of North America

OTHER

Sponsor Role collaborator

University of Reading

OTHER

Sponsor Role lead

Responsible Party

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University of Reading

Principal Investigators

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Jeremy Spencer, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Reading

Locations

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University of Reading

Reading, Berkshire, United Kingdom

Site Status

Countries

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United Kingdom

References

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Rodriguez-Mateos A, Rendeiro C, Bergillos-Meca T, Tabatabaee S, George TW, Heiss C, Spencer JP. Intake and time dependence of blueberry flavonoid-induced improvements in vascular function: a randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity. Am J Clin Nutr. 2013 Nov;98(5):1179-91. doi: 10.3945/ajcn.113.066639. Epub 2013 Sep 4.

Reference Type DERIVED
PMID: 24004888 (View on PubMed)

Other Identifiers

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UReading-2-2011

Identifier Type: -

Identifier Source: org_study_id

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