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The Impact of Dietary Flavanols on the Gut Microflora

This study has been completed.
Information provided by:
University of Reading Identifier:
First received: March 23, 2010
Last updated: NA
Last verified: March 2008
History: No changes posted
The primary propose of this study is to determine the impact of flavanol-rich cocoa on the growth of the human gut microbiota.

Condition Intervention
Intestinal Bacteria Growth
Dietary Supplement: Low flavanol cocoa beverage
Dietary Supplement: High flavanol cocoa beverage

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Participant, Investigator)
Primary Purpose: Basic Science
Official Title: Prebiotic Evaluation of Cocoa-derived Flavanols in Healthy Humans Using a Randomized, Double Blind, Crossover, Placebo-controlled Intervention Study

Further study details as provided by University of Reading:

Primary Outcome Measures:
  • Faecal bacteria numbers using 16S rRNA targeted oligonucleotide probes analysis and fluorescence in situ hybridization [ Time Frame: baseline and 4 weeks ]
    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.

Secondary Outcome Measures:
  • Blood pressure [ Time Frame: Baseline, 4 weeks ]

Enrollment: 22
Study Start Date: January 2008
Study Completion Date: December 2009
Primary Completion Date: December 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: Low Flavanol
Low flavanol drink containing 23 mg of total flavanols. Macro- and micro-nutrient matched with active comparator
Dietary Supplement: Low flavanol cocoa beverage
23 mg of total flavanols from cocoa
Active Comparator: High Flavanols
High Flavanol drink containing 495 mg of total flavanols
Dietary Supplement: High flavanol cocoa beverage
495 mg of total flavanols from cocoa

Detailed Description:
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.

Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

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.
  Contacts and Locations
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Please refer to this study by its identifier: NCT01091922

United Kingdom
University of Reading
Reading, Berkshire, United Kingdom, RG2 9AR
Sponsors and Collaborators
University of Reading
Principal Investigator: Jeremy Spencer, PhD University of Reading
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Dr Jeremy P E Spencer, University of Reading Identifier: NCT01091922     History of Changes
Other Study ID Numbers: UReading-2009-01
Study First Received: March 23, 2010
Last Updated: March 23, 2010

Keywords provided by University of Reading:
bacteria processed this record on April 28, 2017