Effect of Polyphenol-rich Dark Chocolate on Obesity
Sleutelwoorden
Abstract
Omschrijving
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.
Datums
Laatst geverifieerd: | 08/31/2009 |
Eerste ingediend: | 12/28/2008 |
Geschatte inschrijving ingediend: | 12/28/2008 |
Eerst geplaatst: | 12/29/2008 |
Laatste update ingediend: | 09/16/2009 |
Laatste update geplaatst: | 09/17/2009 |
Werkelijke startdatum van het onderzoek: | 10/31/2008 |
Geschatte primaire voltooiingsdatum: | 09/30/2009 |
Geschatte voltooiingsdatum van het onderzoek: | 11/30/2009 |
Conditie of ziekte
Interventie / behandeling
Dietary Supplement: placebo dark chocolate
Dietary Supplement: polyphenol-rich dark chocolate
Fase
Armgroepen
Arm | Interventie / behandeling |
---|---|
Placebo Comparator: placebo dark chocolate polyphenol-poor dark chocolate | Dietary Supplement: placebo dark chocolate polyphenol-free dark chocolate 20g to be distributed throughout the day for 4 weeks |
Experimental: polyphenol-rich dark chocolate | Dietary Supplement: polyphenol-rich dark chocolate 20g to be distributed throughout the day for 4 weeks |
Geschiktheidscriteria
Leeftijden die in aanmerking komen voor studie | 18 Years Naar 18 Years |
Geslachten die in aanmerking komen voor studie | Female |
Accepteert gezonde vrijwilligers | Ja |
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 |
Resultaat
Primaire uitkomstmaten
1. adiponectin [week 0, 4, 6, 10]
Secundaire uitkomstmaten
1. insulin sensitivity [week 0, 4, 6, 10]
2. blood pressure [week 0, 4, 6, 10]
3. lipid profile [week 0, 4, 6, 10]