Dark Chocolate May Lower Blood Pressure
Eating Dark Chocolate May Also Fight Heart Disease and Diabetes
WebMD News Archive
March 11, 2005 -- Now here's a prescription that chocoholics will gladly
follow: Eat a healthy dose of dark chocolate every day to lower your
blood pressure and reduce your risk of developing diabetes.
A new study shows that eating dark chocolate decreases blood pressure and
improves insulin sensitivity in healthy people. Impaired insulin sensitivity is
a major risk factor for diabetes and reduces the body's ability to process
blood sugar (glucose) effectively.
Researchers say the results show that the antioxidant-rich compounds found
in cocoa and dark chocolate -- known as flavonoids -- have a healthy effect on
blood vessels as well as glucose metabolism.
Flavonoids are a larger family of compounds found in the seeds and skins of
plants, such as grapes, cocoa beans, and citrus fruits. Recent studies have
shown that these compounds may be responsible for many of the heart-healthy
effects associated with red wine and diets rich in fruits and vegetables.
2 New Reasons to Love Dark Chocolate
In the study, which appears in the March issue of the American Journal
of Clinical Nutrition, researchers compared the effects of adding 100
grams (3.5 ounces) of dark chocolate or 90 grams (3.2 ounces) of white
chocolate to the normal diets of 15 healthy Italians.
Dark chocolate is rich in flavonoids due to their high cocoa content, but
white chocolate contains no cocoa, and, therefore, no flavonoids.
The participants ate a daily dose of dark chocolate for 15 days, followed by
a seven-day no-chocolate phase, and then ate the white chocolate for another 15
Researchers found that blood sugar metabolism was significantly improved
after the dark chocolate phase, as evidenced by reduced insulin resistance and
higher insulin sensitivity. But no such healthy effects were found after the
white chocolate phase.
The study also showed that the participants' systolic blood pressure (the
top number in a blood pressure reading) was significantly lower after 15 days
of eating dark chocolate -- an average of 108 mm Hg compared with 114 mm Hg.
Again, no effects were found after eating white chocolate.
Other studies have shown similar effects with other flavonoid-containing
foods, such as tea and wine, on blood pressure.
Researchers say the antioxidant-rich compounds improve blood pressure by
helping the lining of the blood vessels expand and contract better to control
blood flow more effectively.
In an editorial that accompanies the study, Cesar G. Fraga, of the
department of nutrition at the University of California, Davis, says "the
findings of this study are of particular interest in terms of identifying
potentially healthy foods."
He says other studies with flavonoid-containing foods, such as tea and wine,
have shown similar effects on vascular and blood pressure regulation.