Effect of Blueberries on Vascular Function in Healthy Men

This study has been completed.
Sponsor:
Collaborators:
Alpro Foundation
Wild Blueberry Association of North America
Information provided by:
University of Reading
ClinicalTrials.gov Identifier:
NCT01292954
First received: February 9, 2011
Last updated: NA
Last verified: February 2011
History: No changes posted
  Purpose

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


Condition Intervention
Healthy
Dietary Supplement: Blueberries

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Pharmacokinetics/Dynamics Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Effects of Blueberries on Vascular Function and Blood Pressure in Healthy Men

Resource links provided by NLM:


Further study details as provided by University of Reading:

Primary Outcome Measures:
  • Flow-mediated dilation [ Time Frame: 0-6 hours after consumption ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Blueberry polyphenols pharmacokinetics [ Time Frame: 0- 24 h after consumption ] [ Designated as safety issue: No ]
  • Blood Pressure [ Time Frame: 0-6 hours after consumption ] [ Designated as safety issue: No ]
  • Laser Doppler Iontophoresis [ Time Frame: 0-6 hours after consumption ] [ Designated as safety issue: No ]

Enrollment: 10
Study Start Date: October 2010
Study Completion Date: February 2011
Primary Completion Date: January 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Low dose blueberry Dietary Supplement: 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
Active Comparator: medium dose blueberry Dietary Supplement: 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
Active Comparator: high dose blueberry Dietary Supplement: 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
Placebo Comparator: control Dietary Supplement: 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

Detailed Description:

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.

  Eligibility

Ages Eligible for Study:   19 Years to 40 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01292954

Locations
United Kingdom
University of Reading
Reading, Berkshire, United Kingdom, RG6 6AP
Sponsors and Collaborators
University of Reading
Alpro Foundation
Wild Blueberry Association of North America
Investigators
Principal Investigator: Jeremy Spencer, PhD University of Reading
  More Information

No publications provided

Responsible Party: Dr Jeremy Spencer, University of Reading
ClinicalTrials.gov Identifier: NCT01292954     History of Changes
Other Study ID Numbers: UReading-2-2011
Study First Received: February 9, 2011
Last Updated: February 9, 2011
Health Authority: UK:University of Reading Research Ethics Committee

Keywords provided by University of Reading:
blueberries
vascular function
FMD
Blood pressure
Laser Doppler
pharmacokinetics
absorption
metabolism
polyphenols
flavonoids

ClinicalTrials.gov processed this record on August 28, 2014