Dark chocolate lowers blood pressure
One small square of dark chocolate a day could have a clinical effect on blood pressure, according to a preliminary trial from Germany. People aged ,56-74 who ate 6.3 g of dark chocolate for 18 weeks dropped their systolic blood pressure nearly 3 mm Hg more than those given a matching portion of white chocolate . The dark chocolate, which contained 30 m of polyphenols, reduced diastolic blood pressure by a mean of 1.9 mm Hg (1.1 to 2.7).
The researchers think that the flavanols family of polyphenols are probably responsible, mediated by the vasodilator S-nitrosoglutathione. At the end of the trial, serum concentrations of S-nitrosoglutathione were significantly higher in the group given dark chocolate.
The 44 participants had baseline blood pressures between 130/85 and 160/100. They were healthy, reasonably affluent non-smokers with normal body weight and a habitually low-intake of alcohol and chocolate.
JAMA 2007, vol 298, 49-60
- Martin Eastwood