Clinical trial NCT01749020: Effect of Polyphenol-rich Dark Chocolate on Insulin Sensitivity in Normal Weight and Overweight Adults
Official title: Effect of Polyphenol-rich Dark Chocolate on Insulin Sensitivity in Normal Weight and Overweight Adults
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Insulin Resistance
Keywords: Diabetes type II, Insulin sensitivity
Lead sponsor: Queen Margaret University
Sponsor class: OTHER
Collaborators: name: Barry Callebaut
First posted: 2012-12-13
Enrollment: 61
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

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.

Eligibility criteria: 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)

Primary outcomes:
measure: Determine if the consumption of DC rich in polyphenols can induce a change in insulin sensitivity
timeFrame: Baseline and week 4
Secondary outcomes:
measure: Determine if the consumption of DC rich in polyphenols can induce a change in glucose levels
timeFrame: Baseline and week 4
measure: Determine if the consumption of DC rich in polyphenols can induce a change in Lipid profile (TC, HDL, LDL & TG)
timeFrame: Baseline and week 4
measure: Determine if the consumption of DC rich in polyphenols can induce a change in oxidized LDL levels
timeFrame: Baseline and week 4
measure: Determine if the consumption of DC rich in polyphenols can induce a change in BMI and Waist circumference
timeFrame: Baseline and week 4
measure: Determine if the consumption of DC rich in polyphenols can induce a change in blood pressure
timeFrame: Baseline and week 4
measure: Determine if the consumption of DC rich in polyphenols can induce a change in salivary cortisol-to-cortisone ratio
timeFrame: Baseline and week 4
measure: Determine if the consumption of DC rich in polyphenols can induce a change in high sensitivity CRP
timeFrame: Baseline and Week 4
Other outcomes:
Locations:
city: Musselburgh
country: United Kingdom
facility: Queen Margaret University Lab
state: East Lothian
Study officials:
affiliation: Queen Margaret University
name: Emad Al-Dujaili, PhD
role: STUDY_DIRECTOR
References: