NCT00099476

Effects of Dark Chocolate on Insulin Sensitivity in People With High Blood Pressure

Completed Phase 1 Last updated 2 July 2017

What this trial tests

Phase 1 trial testing Effects of dark chocolate in Hypertension in 65 participants. Completed in 16 April 2009.

Timeline

10 December 2004

16 April 2009

Quick facts

Lead sponsor	National Center for Complementary and Integrative Health (NCCIH)
Phase	Phase 1
Status	Completed
Study type	INTERVENTIONAL
Primary purpose	treatment
Enrollment	65
Start date	10 December 2004
Estimated completion	16 April 2009
Sites	1 location across United States

Drugs / interventions tested

• Effects of dark chocolate

Conditions studied

• Hypertension — all drugs for Hypertension →

Sponsor

National Center for Complementary and Integrative Health (NCCIH) — full company profile →

Who can join

Adults 21 to 65, any sex, with Hypertension. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

This study will examine whether dark chocolate affects the way patients with hypertension (high blood pressure) respond to insulin, a hormone secreted by the pancreas that regulates blood glucose (sugar) levels. In many people with hypertension, insulin is not as effective in helping the body use glucose. This is called insulin resistance. Insulin also increases blood flow into muscle by opening inactive blood vessels. Laboratory studies suggest that eating dark chocolate may improve blood pressure. This study will determine whether dark chocolate improves insulin resistance or changes how blood vessels react to insulin in hypertensive people.

People between 21 and 65 years of age who have high blood pressure and are not pregnant may be eligible for this study. Candidates are screened with a medical history, physical examination, and blood and urine tests.

Participants refrain from eating foods containing chocolate or cocoa for 1 week and then come to the clinic on three separate occasions 3 weeks apart for a glucose clamp test and contrast ultrasound, described below. At the first glucose clamp test, subjects are randomly assigned to drink either a cocoa drink with high anti-oxidant content or one with a very low content of anti-oxidant. Each drink will be taken twice a day for 2 weeks. At the end of the 2 weeks, they return for a second glucose clamp test. At the second test, they stop taking the cocoa drink for 1 week and then start again for another 2 weeks. For this 2-week period, those who were given the high anti-oxidant content cocoa drink the first 2 weeks will take the placebo, very low anti-oxidant drink this time, and those who took the placebo will now have the high anti-oxidant cocoa drink. After this 2 weeks of taking the cocoa drink or placebo, they then take the third and last glucose clamp test.

Glucose clamp test: This test measures how the body responds to insulin. Subjects fast the night before each test and do not eat until the test is over, usually in the early afternoon. For the test, the subject lies in a bed or reclines in a chair. A needle is placed in a vein in each arm - one for collecting blood samples and the other for infusing glucose, insulin, and a potassium solution. Blood glucose and insulin levels are measured frequently during the test and the rate of the glucose infusion is adjusted to keep blood glucose at the baseline (fasting) level. Blood samples are tested for blood count, electrolytes, liver function...

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

1. Cocoa consumption for 2 wk enhances insulin-mediated vasodilatation without improving blood pressure or insulin resistance in essential hypertension.
   Muniyappa R, Hall G, Kolodziej TL, Karne RJ, et al · · 2008 · cited 97× · PMID 19064532 · DOI 10.3945/ajcn.2008.26457