Flavonoid-rich cocoa supplement reverses arterial stiffness and decreases blood pressure.

Arterial stiffness, a condition in which the walls of arteries become more rigid, increases with age and is a strong risk factor for hypertension. The links between arterial stiffness and hypertension are likely bidirectional, with aortic stiffening driving increases in systolic pressure, and elevated pressures promoting vascular damage and accelerated stiffening. Findings from a new study suggest that flavonoid compounds in cocoa reverse arterial stiffness.

Cocoa, the principal component of chocolate, is derived from the cacao tree. A wide range of beneficial health effects have been attributed to consumption of cocoa and chocolate, especially dark chocolate, which is rich in flavonoids. Cocoa and chocolate have the highest concentrations of flavonoids among commonly consumed foods, with roughly 10 percent of the weight of cocoa powder coming from flavonoids. Robust evidence suggests that cocoa flavonoids improve blood flow, lower blood pressure, promote healthy blood lipid concentrations, lower the risk of cardiovascular disease, protect the skin against the sun, and improve blood flow to the brain.

The investigators conducted a series of single-person trials in 11 healthy adults. Participants consumed six cocoa flavonoid capsules (providing 862 milligrams of cocoa flavonoids) every morning on alternating days for eight consecutive days. On days when they didn’t take the cocoa flavonoid capsules, they took a placebo. Participants wore devices that measured their blood pressure, heart rate, and pulse wave velocity (a measure of arterial stiffness) before and every 30 minutes for the first three hours after taking the capsules and then every hour afterward for a total of 12 hours per day.

The investigators found that when the participants took the cocoa supplement, the participants' blood pressure dropped by as much as 1.7 mmHg and their pulse wave velocity decreased by as much as 0.14 m/s. These effects were observed only if the participant had high blood pressure. The greatest effects occurred in the first three hours after taking the cocoa, with the blood pressure dropping approximately 5 mmHg. Blood pressures dropped again at approximately eight hours after consuming the cocoa supplement, likely due to bacterial metabolism of the flavonoids in the gut.

These findings suggest that a flavonoid-rich cocoa supplement reduces blood pressure and markers of arterial stiffness in people with high blood pressure. Larger studies are needed to confirm these findings.

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