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Effect of Polyphenol-rich Dark Chocolate on Obesity

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified September 2009 by Queen Margaret University.
Recruitment status was:  Active, not recruiting
Information provided by:
Queen Margaret University Identifier:
First received: December 29, 2008
Last updated: September 17, 2009
Last verified: September 2009

This study aims to investigate the effect of polyphenol-rich dark chocolate (DC) on insulin resistance, adiponectin , blood pressure (BP), lipid profile in obese subjects and determine possible associations between all assessed parameters.

It hypothesizes that consumption of polyphenol-rich Dc could lower fasting glucose levels, insulin resistance and improve BP, total cholesterol, low-density lipoprotein (LDL) and triglycerides while increasing adiponectin and high-density lipoprotein (HDL) in overweight or obese individuals.

Condition Intervention Phase
Dietary Supplement: placebo
Dietary Supplement: Acticoa polyphenol-rich dark chocolate
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single Blind (Participant)
Primary Purpose: Prevention
Official Title: Effect of Polyphenols on Glucoregulatory Biomarkers, Blood Pressure and Lipid Profile in Overweight and Obese Subjects

Further study details as provided by Queen Margaret University:

Primary Outcome Measures:
  • adiponectin [ Time Frame: week 0, 4, 6, 10 ]

Secondary Outcome Measures:
  • insulin sensitivity [ Time Frame: week 0, 4, 6, 10 ]
  • blood pressure [ Time Frame: week 0, 4, 6, 10 ]
  • lipid profile [ Time Frame: week 0, 4, 6, 10 ]

Estimated Enrollment: 50
Study Start Date: November 2008
Estimated Study Completion Date: December 2009
Estimated Primary Completion Date: October 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: placebo dark chocolate
polyphenol-poor dark chocolate
Dietary Supplement: placebo
polyphenol-free dark chocolate 20g to be distributed throughout the day for 4 weeks
Other Name: barry callebaut
Experimental: polyphenol-rich dark chocolate Dietary Supplement: Acticoa polyphenol-rich dark chocolate
20g to be distributed throughout the day for 4 weeks
Other Name: barry callebaut, acticoa

Detailed Description:

It is well acknowledged that the main mechanism by which cocoa and DC polyphenols improve fasting glucose levels, insulin sensitivity, BP and lipid profile in healthy individuals and those with hypertension and/or impaired glucose-tolerance, involves increased nitric oxide (NO) bioavailability. NO is essential for the regulation of blood pressure, glucose and lipid balance. This is evident in that e-NOsynthase knockout mice exhibit insulin resistance, hypertension and hyperlipidemia, a cluster of diseases that is also observed in the metabolic syndrome. Recently, it was shown that adiponectin regulates eNOsynthase activity through the phosphatidylinositol 3-kinase-dependent pathway wherein eNOsynthase is phosphorylated by 5'-AMP-activated protein kinase at Ser1179 and that plasma adiponectin levels are inversely correlated with BMI, waist-to-hip ratio, fasting plasma glucose, insulin, triglyceride, hyperinsulinemia, and glucose intolerance and positively with HDL-cholesterol, but not BP. This suggests a strong link between impaired NO bioavailability, adiponectin levels and obesity. Indeed, apart from exhibiting impaired NO bioavailability, obese individuals also have decreased plasma adiponectin levels. Since cocoa and DC are known to modulate NO activity, investigating the impact of cocoa or DC polyphenols on adiponectin levels and observing a correlation between its levels and improved fasting glucose levels, insulin resistance, BP and lipid profile is essential in improving our understanding of the relationship between diet and health, particularly that polyphenols in apples, oolong and green tea polyphenols have been previously shown to influence adiponectin levels.

This study uses a randomised single-blind, placebo-controlled design. Following a 1-week run-in phase, each group will be randomised to one of the two groups: placebo-polyphenol-rich DC, polyphenol-rich DC-placebo. Subjects will follow each diet for 4weeks, after which they will cross-over to the next diet separated by a 2-week washout period and until each subject completes both interventions.


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

Inclusion Criteria:

  • Healthy female volunteers
  • Aged 18-50 years
  • Group 1 will consist of volunteers with BMI of 18-25 kg/m2
  • Group 2 will consist of women with BMI of 25-35 kg/m2

Exclusion Criteria:

  • Cardiovascular disease
  • Hypertension
  • Diabetes
  • Smokers
  • People taking dietary supplements
  • Hypertension or cholesterol-lowering drugs
  • Those with high cocoa or DC intake, soy or nut allergies
  Contacts and Locations
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Please refer to this study by its identifier: NCT00815451

United Kingdom
Queen margaret university
Musselburgh, East Lothian, United Kingdom, eh21 6uu
Sponsors and Collaborators
Queen Margaret University
Principal Investigator: suzana h almoosawi, BScHons HN QMU
  More Information

Responsible Party: suzana almoosawi, PhD student QMU Identifier: NCT00815451     History of Changes
Other Study ID Numbers: 1-salmoosawi
Study First Received: December 29, 2008
Last Updated: September 17, 2009

Additional relevant MeSH terms:
Nutrition Disorders
Body Weight
Signs and Symptoms processed this record on April 28, 2017