Ingestion of Dark Chocolate Lowers Blood Pressure and Improves Insulin Sensitivity

Category: Conditions of the Circulatory System

Numerous studies have documented the protective effects that cocoa and chocolate exert on the lining of blood vessels. The compounds responsible for this effect are believed to be flavonoids, in particular a sub-class known as flavonols.

Two flavonols, epicatechin and catechin (along with their procyanidins), are found in high levels in dark chocolate, but are absent in white chocolate. A previous study found that dark chocolate could lower blood pressure in elderly individuals with high blood pressure. The mechanism appears to be mediated by nitric oxide (NO).

A recent study published in the February issue of American Journal of Clinical Nutrition investigated the effects that dark chocolate has on insulin sensitivity and blood pressure in healthy individuals. The authors hypothesized that dark chocolate may be able to modulate the insulin response via NO.

The study included 15 healthy subjects who consumed 100 grams of dark chocolate with approximately 500mg of flavonols compared to the consumption of 90 grams of white chocolate with no flavonols by the control group. Outcome variables were assessment of insulin resistance and insulin sensitivity. Blood pressure was also measured daily.

The study found that insulin sensitivity was higher after ingestion of dark chocolate and the assessment of insulin resistance was decreased in the dark chocolate group compared to the white chocolate group. The results were statistically significant. The dark chocolate group also had lower systolic blood pressure compared to the white chocolate group, even though all values were within the normal range.

The study concluded that flavonols, epicatechin, and catechin in dark chocolate might be responsible for mediating insulin sensitivity and blood pressure via nitric oxide. This effect was observed in small study of healthy individuals. Larger studies are needed to confirm the effects.

Posted by Kristopher Foster on December 1, 2008 10:00 AM