Dose-dependent Effects of Blueberry Polyphenols on Endothelial Function in Healthy Individuals

Study Overview
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Brief Summary
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The purpose of this study is to assess the impact of acute blueberry polyphenol intake on endothelial function 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 blueberry polyphenols on blood vessel function using Flow mediated dilation (FMD) to measure endothelial function. The study will not only measure the acute effects of flavonoid ingestion on vascular reactivity but will also assess plasma polyphenol metabolite levels.

Official Title
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Dose-dependent Effects of Blueberry Polyphenols on Endothelial Function in Healthy Individuals

Conditions
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Endothelial Function

Intervention / Treatment
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* Dietary Supplement: Freeze-dried blueberry powder dissolved in water
* Dietary Supplement: Control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male 18-40 years Healthy signed consent form Exclusion Criteria: Blood pressure > 140/90 mmHg Had suffered a myocardial infarction or stroke 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 Allergies or intolerances to any foods Smoker Heavy drinker (>21 units per week) On any lipid-modifying medication On any blood pressure lowering medication On any medication affecting blood clotting Taking high dose fish oil supplements (greater then 1 g EPA and DHA per day) or high doses of antioxidant vitamins (greater then 800 μg vitamin A, 60 mg vitamin C, 10 mg vitamin E or 400 μg beta carotene) Taking probiotics, prebiotics, synbiotics, antibiotics or anti-inflammatory or blood lowering medication within a 2-month period prior to the study Planning on altering consumption of vitamin supplements/fish oil capsules during the course of the study Undertakes strenuous exercise > 4 times per week for > 1 hour per session Haemoglobin levels below reference range provided by the Royal Berkshire Hospital

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 319 mg blueberry polyphenols<br>Freeze-dried blueberry powder dissolved in water | Dietary Supplement: Freeze-dried blueberry powder dissolved in water<br>* Wild blueberry freeze-dried powder dissolved in water<br>|
| Active Comparator: 639 mg blueberry polyphenols<br>Freeze-dried blueberry powder dissolved in water | Dietary Supplement: Freeze-dried blueberry powder dissolved in water<br>* Wild blueberry freeze-dried powder dissolved in water<br>|
| Active Comparator: 766 mg blueberry polyphenols<br>Freeze-dried blueberry powder dissolved in water | Dietary Supplement: Freeze-dried blueberry powder dissolved in water<br>* Wild blueberry freeze-dried powder dissolved in water<br>|
| Active Comparator: 1466 mg blueberry polyphenols<br>Freeze-dried blueberry powder dissolved in water | Dietary Supplement: Freeze-dried blueberry powder dissolved in water<br>* Wild blueberry freeze-dried powder dissolved in water<br>|
| Active Comparator: 1791 mg total blueberry polyphenols<br>Freeze-dried blueberry powder dissolved in water | Dietary Supplement: Freeze-dried blueberry powder dissolved in water<br>* Wild blueberry freeze-dried powder dissolved in water<br>|
| Placebo Comparator: O mg blueberry polyphenols<br>Macro- and micronutrient matched control drink | Dietary Supplement: Control<br>* Macro- and micro-nutrient matched control in water<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flow-mediated dilation |  | 0-1 hour after consumption | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| plasma blueberry polyphenol metabolites |  | 0-1 h after consumption | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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flow-mediated dilation, blueberry polyphenols, dose-dependency