Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results.
Merely thinking of chocolate may set pulses racing, but research suggests it can actually lower blood pressure. Daily consumption of dark chocolate or cocoa powder caused a slight reduction in blood pressure readings, a review of study evidence showed. Although the effect was small, it was potentially enough to help protect people from heart disease, said experts.
Scientists analysed data from trials in which people consumed daily helpings of dark chocolate or cocoa powder. The chocolate products contained varying amounts of plant compounds called flavanols that are believed to benefit health. A total of 856 people took part in 20 trials lasting an average of two to eight weeks. The most flavanol-rich chocolate or cocoa was found to lower blood pressure by an average of two to three millimetres of mercury. When chocolate or cocoa powder was compared with flavanol-free products, the beneficial effects were more pronounced. In this case, blood pressure reductions of up to four millimetres of mercury were seen.
Dark chocolate is superior to placebo in reducing systolic hypertension or diastolic prehypertension. Flavanol-rich chocolate did not significantly reduce mean blood pressure below 140 mmHg systolic or 80 mmHg diastolic.
The link between cocoa and blood pressure first emerged from the indigenous people of San Blas Island in Central America. They drink flavanol-rich cocoa drinks every day and have normal blood pressure regardless of age. Flavanol concentrations in cocoa and chocolate vary greatly between different products.
As a dietitian for patients with high blood pressure, I often find myself "ruining" their dietary lives by restricting their salt and carbs. I can sometimes redeem myself by suggesting a little chocolate! We recommend chocolate with high cocoa content (70 percent). And, of course, modest amounts.