Effect of Polyphenol-rich Dark Chocolate on Obesity

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00815451
Recruitment Status : Unknown
Verified September 2009 by Queen Margaret University.
Recruitment status was:  Active, not recruiting
First Posted : December 30, 2008
Last Update Posted : September 18, 2009
Information provided by:
Queen Margaret University

Brief Summary:

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 or disease Intervention/treatment Phase
Obesity Dietary Supplement: placebo Dietary Supplement: Acticoa polyphenol-rich dark chocolate Phase 2

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.

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 50 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Participant)
Primary Purpose: Prevention
Official Title: Effect of Polyphenols on Glucoregulatory Biomarkers, Blood Pressure and Lipid Profile in Overweight and Obese Subjects
Study Start Date : November 2008
Estimated Primary Completion Date : October 2009
Estimated Study Completion Date : December 2009

Arm Intervention/treatment
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

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

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

Information from the National Library of Medicine

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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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): 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

Responsible Party: suzana almoosawi, PhD student QMU Identifier: NCT00815451     History of Changes
Other Study ID Numbers: 1-salmoosawi
First Posted: December 30, 2008    Key Record Dates
Last Update Posted: September 18, 2009
Last Verified: September 2009

Additional relevant MeSH terms:
Nutrition Disorders
Body Weight
Signs and Symptoms