Effect of Polyphenol-rich Dark Chocolate on Obesity

NCT ID: NCT00815451

Last Updated: 2009-09-18

Basic Information

• Recruitment Status: UNKNOWN
• Clinical Phase: PHASE2
• Total Enrollment: 50 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2008-11-30
• Study Completion Date: 2009-12-31

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.

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.

Conditions

Obesity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: PREVENTION
• Blinding Strategy: SINGLE

Study Groups

placebo dark chocolate

polyphenol-poor dark chocolate

Group Type: PLACEBO_COMPARATOR

placebo

Intervention Type: DIETARY_SUPPLEMENT

polyphenol-free dark chocolate 20g to be distributed throughout the day for 4 weeks

polyphenol-rich dark chocolate

Group Type: EXPERIMENTAL

Acticoa polyphenol-rich dark chocolate

Intervention Type: DIETARY_SUPPLEMENT

20g to be distributed throughout the day for 4 weeks

Interventions

placebo

polyphenol-free dark chocolate 20g to be distributed throughout the day for 4 weeks

Intervention Type: DIETARY_SUPPLEMENT

Acticoa polyphenol-rich dark chocolate

20g to be distributed throughout the day for 4 weeks

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

barry callebaut; barry callebaut, acticoa

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

Queen Margaret University

OTHER

Sponsor Role: lead

Responsible Party

PhD student QMU

Principal Investigators

suzana h almoosawi, BScHons HN

Role: PRINCIPAL_INVESTIGATOR

QMU

Locations

Queen margaret university

Musselburgh, east lothian, United Kingdom

Countries

United Kingdom

Other Identifiers

1-salmoosawi

Identifier Type: -

Identifier Source: org_study_id