The July 4 issue of JAMA indicates that eating about 30 calories a day of dark chocolate was associated with a lowering of blood pressure, without weight gain or other adverse effects. Good news for chocolate lovers!
The consumption of high amounts of cocoa-containing foods can lower blood pressure, (reported earlier in Sham vs. Wham) and this is believed to be due to the action of the cocoa polyphenols (a group of chemical substances found in plants). However, of particular concern in previous studies is that the potential BP reduction contributed by the flavanols could be offset by the high sugar, fat and calorie intake with the cocoa products.
At the University Hospital in Cologne, Germany, Dr. Dirk Taubert and colleagues assessed the effects of low regular amounts of cocoa on blood pressure. The trial, conducted between January 2005 and December 2006, included 44 adults (age 56 through 73 years; 24 women, 20 men) with untreated upper-range prehypertension (BP 130/85 – 139/89) or stage 1 hypertension (BP 140/90 – 160/100). Participants were randomly assigned to receive for 18 weeks either 6.3 g (30 calories) per day of dark chocolate containing 30 mg polyphenols or matching polyphenol-free white chocolate.
The researchers found the dark chocolate intake reduced average systolic BP by −2.9 (1.6) mm Hg and diastolic BP by −1.9 (1.0) mm Hg without changes in body weight, plasma levels of lipids or glucose. Hypertension prevalence declined from 86 percent to 68 percent. Systolic and diastolic blood pressure remained unchanged throughout the treatment period for those in the control group who were eating white chocolate.
Although the magnitude of the BP reduction was small, the effects are clinically noteworthy because on a population basis, it has been estimated that a 3-mm Hg reduction in systolic BP would reduce the relative risk of stroke mortality by 8 percent of coronary artery disease mortality by 5 percent, and of all-cause mortality by 4 percent. These numbers represent significant improvements in death and stroke.
The authors report that "The most intriguing finding of this study is that small amounts of commercial cocoa confectionary convey a similar BP-lowering potential compared with comprehensive dietary modifications that have proven efficacy to reduce cardiovascular event rate. Whereas long-term adherence to complex behavioral changes is often low and requires continuous counseling, adoption of small amounts of flavanol-rich cocoa into the habitual diet is a dietary modification that is easy to adhere to and therefore may be a promising behavioral approach to lower blood pressure in individuals with above-optimal blood pressure."
That's just a complicated way of saying that eating a small piece of dark chocolate every day is an easy thing for people to do, and the fact that it is good for them ends up as a great bonus!