High blood pressure is an important risk factor for cardiovascular disease, contributing to about half the cardiovascular events, such as strokes and heart attacks, worldwide and around a third of cardiovascular-related deaths. Evidence from epidemiological studies has suggested that cocoa might reduce this risk, the possible explanation being that cocoa contains flavonols, which are responsible for the formation of nitric oxide in the body, and nitric oxide causes blood vessel walls to relax and open wider, thereby reducing blood pressure.
Our new Cochrane Review of 20 randomised trials updated previous reviews with fewer trials, and has shown dark chocolate and flavonol-rich cocoa products to effectively reduce blood pressure by 2–3 mm of mercury. The reviewed trials involved nearly 900 people consuming 3–100 g of dark chocolate or cocoa powder each day (containing 30–1000 mg of flavonols) usually for 2–8 weeks and, in one study, for 18 weeks. The reduction in blood pressure achieved with cocoa is somewhat comparable to other lifestyle modifications, such as diet and exercise (3–5 mm Hg reduction), and may serve as a complementary treatment option.
As studies in our review were of short duration, longer-term studies are needed to look into long-term effects. Available data did not allow any recommendations regarding optimal dosage. Smaller dosages may be as...
