The Irresistible Treat That Might Help Resistance
© Jose Antonio SantisoDark Chocolate
Chocolate is irresistible—or nearly so—to many people. Could it possibly help with a health problem involving insulin resistance and blood sugar? Michael Quon, M.D., Ph.D., Chief of the Diabetes Unit in NCCAM's Division of Intramural Research, is trying to find out.
He and his colleagues have begun a study on whether dark chocolate improves insulin resistance. In a person who has insulin resistance, his body has a harder time than other people's bodies in using glucose, a simple sugar made from carbohydrates during digestion. Insulin resistance usually has no symptoms, but may lead to diabetes. People with obesity, high blood pressure, heart disease, and/or other conditions are the ones who most often have it; getting older, lack of exercise, and a family history of diabetes can raise the risk.
CAM at the NIH asked Dr. Quon some questions about the study.
Q: What evidence is there so far that dark chocolate may have an effect on insulin resistance?
A: Right now there is very little. However, there are a number of published clinical studies showing that dark chocolate may improve blood pressure and blood vessel function in people with hypertension (high blood pressure). This may be due to a substance in cocoa called epicatechin (pronounced "eh-pih-kah-TEK-in"). Studies in our lab and others suggest that insulin resistance may explain the link between hypertension and diabetes. It's interesting that some conventional drugs for treating hypertension also improve insulin resistance, and vice versa. Our idea is that the epicatechin in dark chocolate may lower blood pressure and improve insulin resistance at the same time and in similar ways.
Q: Can you tell us about the preparation used in the study? Why did you use dark chocolate rather than milk chocolate?
A: The cocoa we are using is highly enriched with epicatechin. Participants consume about 900 mg of it in a cocoa drink, which has about 240 calories. In the placebo (or inactive substance) part of the trial, participants drink a cocoa that has not been enriched this way. Other forms of chocolate—such as milk chocolate—do not contain as much epicatechin as dark chocolate.
Dr. Quon(left, with Dr. Edward Li and
Dr. Michelle Vincent) is leading NCCAM's dark chocolate study.
Q: People might jump on the idea that chocolate may actually have health benefits. Is there enough evidence there for people to eat more chocolate? And are there any concerns about unwanted side effects, such as weight gain?
A: There is growing evidence that dark chocolate may have important health benefits. However, we need to find out more—it is too early to recommend that people consume more chocolate for health purposes. Also, the chocolate that is commercially available does not have consistent amounts of epicatechin, and thus consumers have no way of knowing which commercial chocolate, if any, may be beneficial.
Any food that has beneficial health effects may also cause weight gain if you eat too much of it. Another potential concern with chocolate is that the cocoa butter contains fats that may raise cholesterol levels. However, the major type of fat in chocolate—stearic acid—does not affect cholesterol levels, so this may be less of a concern.
At press time, this study was still recruiting volunteers within traveling distance to the NIH Clinical Center in Bethesda, Maryland
(see www.clinicaltrials.gov/show/NCT00099476 or contact the
NCCAM Clearinghouse.
For more about insulin resistance, see www.diabetes.niddk.nih.gov/dm/pubs/insulinresistance.
