Skip to main content
OpenTrials
Completed

NCT Number: NCT01749020

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

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

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Insulin Resistance Diabetes Mellitus Diabetes Mellitus, Type 2 Endocrine System Diseases Glucose Metabolism Disorders Hyperinsulinism Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Queen Margaret University Lab

Musselburgh, East Lothian, EH21 6UU, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Polyphenol-rich Dark chocolate

Other

Participants will be asked to consume 20g of dark chocolate containing 500mg of polyphenols daily for a period of 4 weeks

Placebo Dark chocolate

Other

Participants will be asked to consume 20g of dark chocolate containing little or no polyphenols for a period of 4 weeks

Primary outcomes

  1. Determine if the consumption of DC rich in polyphenols can induce a change in insulin sensitivity

    Time frame: Baseline and week 4

    Insulin sensitivity will be determined by determined by HOMA-IR (Homeostasis Model of Assessment - Insulin Resistance)

Secondary outcomes

  1. Determine if the consumption of DC rich in polyphenols can induce a change in glucose levels

    Time frame: Baseline and week 4

  2. Determine if the consumption of DC rich in polyphenols can induce a change in Lipid profile (TC, HDL, LDL & TG)

    Time frame: Baseline and week 4

  3. Determine if the consumption of DC rich in polyphenols can induce a change in oxidized LDL levels

    Time frame: Baseline and week 4

  4. Determine if the consumption of DC rich in polyphenols can induce a change in BMI and Waist circumference

    Time frame: Baseline and week 4

  5. Determine if the consumption of DC rich in polyphenols can induce a change in blood pressure

    Time frame: Baseline and week 4

  6. Determine if the consumption of DC rich in polyphenols can induce a change in salivary cortisol-to-cortisone ratio

    Time frame: Baseline and week 4

  7. Determine if the consumption of DC rich in polyphenols can induce a change in high sensitivity CRP

    Time frame: Baseline and Week 4

Sponsors and collaborators

Lead sponsor

Queen Margaret University

Other

Collaborators

  • Barry Callebaut

Registry information

Important dates

Study start
2012
Primary completion
2013
Study completion
2013
First posted
Dec 13, 2012
Registry last updated
Nov 20, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.