Effect of Polyphenol-rich Dark Chocolate on Insulin Sensitivity in Normal Weight and Overweight Adults

Not Applicable

Completed

• Conditions: Insulin Resistance
• Interventions: Other: Polyphenol-rich Dark chocolate; Other: Placebo Dark chocolate

• Registration Number: NCT01749020
• Lead Sponsor: Queen Margaret University

Brief Summary

The purpose of the study is to determine the effect of polyphenol-rich dark chocolate on insulin sensitivity in normal weight and overweight adults.

Detailed Description

Polyphenols may have several favourable effects on health. Dark chocolate (DC) is one of the highest sources of polyphenols in foods. The aim of the study is to determine the effect of polyphenol-rich dark chocolate on insulin sensitivity in normal weight and overweight adults. Seventy four volunteers with no history of hypertension, cardiovascular diseases or diabetes will be recruited. Participants will randomly receive 20g daily of one of the two different types of DC: Placebo DC (low in polyphenols) or DC rich in polyphenols (500mg) for a period of four weeks. Participants will be asked to make two appointments to the university clinical lab. Anthropometric measurements (height, weight, waist circumference), blood and saliva samples will be taken during each of the 2 visits. Compliance will be tested by the measure of total polyphenols in a 24-hour urine sample in some random samples before and at the end of the intervention. To monitor any fluctuations in the participants' diet or physical activity during the study period, a three-day diet diary and a physical activity questionnaire will be collected before the start of the study and after four weeks. Data will be analysed with an ANCOVA with time (pre- and post-) and treatment (DC and placebo) as between-subject factor.

Study Timeline

• Study Start: 2012-03
• Study First Submitted: 2012-12-10
• Study First Submitted QC: 2012-12-12
• Study First Posted: 2012-12-13
• Primary Completion: 2013-07
• Study Completion: 2013-07
• Status Verified: 2013-11
• Last Update Submitted: 2013-11-19
• Last Update Posted: 2013-11-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 61

Inclusion Criteria

• Adults with no history of hypertension, diabetes and cardiovascular diseases
• BMI from 18-24.9 and BMI >25
• Males and Females
• Age: 18-65 years

Exclusion Criteria

• Participants with cardiovascular diseases, hypertension or diabetes
• Smokers and heavy alcohol drinkers
• Participants taking any medications that affect insulin, cholesterol, triglycerides or blood pressure
• Participants taking dietary supplements containing high doses of antioxidants
• Postmenopausal women taking HRT (Hormone Replacement Therapy)
• Participants who recently participated or are currently on a weight management program
• Participants with regular consumption of cocoa or DC (> 1 serving/week)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Polyphenol-rich Dark chocolate	Polyphenol-rich Dark chocolate	Dark chocolate with 500 mg of polyphenols
Placebo Dark chocolate	Placebo Dark chocolate	This chocolate contains little or no polyphenols

Primary Outcome Measures

Name	Time	Method
Determine if the consumption of DC rich in polyphenols can induce a change in insulin sensitivity	Baseline and week 4	Insulin sensitivity will be determined by determined by HOMA-IR (Homeostasis Model of Assessment - Insulin Resistance)

Secondary Outcome Measures

Name	Time	Method
Determine if the consumption of DC rich in polyphenols can induce a change in oxidized LDL levels	Baseline and week 4
Determine if the consumption of DC rich in polyphenols can induce a change in BMI and Waist circumference	Baseline and week 4
Determine if the consumption of DC rich in polyphenols can induce a change in blood pressure	Baseline and week 4
Determine if the consumption of DC rich in polyphenols can induce a change in glucose levels	Baseline and week 4
Determine if the consumption of DC rich in polyphenols can induce a change in Lipid profile (TC, HDL, LDL & TG)	Baseline and week 4
Determine if the consumption of DC rich in polyphenols can induce a change in salivary cortisol-to-cortisone ratio	Baseline and week 4
Determine if the consumption of DC rich in polyphenols can induce a change in high sensitivity CRP	Baseline and Week 4

Trial Locations

Locations (1)

Queen Margaret University Lab; 🇬🇧 Musselburgh, East Lothian, United Kingdom