The Impact of Dietary Flavanols on the Gut Microflora

Study Overview
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Brief Summary
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The primary propose of this study is to determine the impact of flavanol-rich cocoa on the growth of the human gut microbiota.

Detailed Description
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A randomised, placebo-controlled, double-blind, cross-over human intervention study will be conducted in 20 healthy human volunteers to test the impact of a high-flavanol containing meal on the growth of the large intestinal bacteria (microflora). The high flavanol test meal will contain 495 mg of flavanols and the low flavanol control will contain 23 mg of flavanols. The two intervention diets are otherwise matched for macro- and micronutrient content. Changes in the gut microbiota will be determined by measuring bacterial population levels in human faecal material using 16S rRNA targeted oligonucleotide probes and fluorescence in situ hybridization. A number of other biochemical and physiological measures will be recorded including blood glucose, lipoproteins, cytokine levels and blood pressure.

Official Title
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Prebiotic Evaluation of Cocoa-derived Flavanols in Healthy Humans Using a Randomized, Double Blind, Crossover, Placebo-controlled Intervention Study

Conditions
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Intestinal Bacteria Growth

Intervention / Treatment
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* Dietary Supplement: Low flavanol cocoa beverage
* Dietary Supplement: High flavanol cocoa beverage


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: a signed consent form age of 18-50 years inclusive BMI between 20-26 Exclusion Criteria: pregnant or lactating allergy to milk products sensitivity to alkaloids and/or caffeine gastrointestinal disorders (e.g., chronic constipation, diarrhoea, inflammatory bowel disease, -inflammatory bowel syndrome, or other chronic gastrointestinal complaints) diabetes mellitus hypertension (>150/90 mm/Hg) anaemia and gall bladder problems not consuming probiotics, prebiotics, antibiotics or anti-inflammatory or blood lowering medication within a 2-month period prior to the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Low Flavanol<br>Low flavanol drink containing 23 mg of total flavanols. Macro- and micro-nutrient matched with active comparator | Dietary Supplement: Low flavanol cocoa beverage<br>* 23 mg of total flavanols from cocoa<br>|
| Active Comparator: High Flavanols<br>High Flavanol drink containing 495 mg of total flavanols | Dietary Supplement: High flavanol cocoa beverage<br>* 495 mg of total flavanols from cocoa<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Faecal bacteria numbers using 16S rRNA targeted oligonucleotide probes analysis and fluorescence in situ hybridization | Measurements of the growth rate and number of bacterial species in human faecal samples using 16S rRNA targeted oligonucleotide probes and fluorescence in situ hybridisation. | baseline and 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood pressure |  | Baseline, 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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flavonoids, flavanols, bacteria