= Registered users
= Paid-up subscribersThe results of a large study have added to the slowly accumulating body of evidence suggesting that dark or flavanol-rich chocolate can reduce the risk of cardiovascular disease (CVD), probably by enhancing nitric oxide release and lowering blood pressure.
This trial by Buijsse and colleagues is the largest observational study to date to examine the association between chocolate consumption and risk of CVD. A total of 19,357 people, aged 35-65, were enrolled from the Potsdam arm of the European Prospective Investigation into Cancer and Nutrition (EPIC) trial. All had blood pressure, height and weight measurements recorded at the start of the study, 1994-1998, and provided information about their diet, lifestyle, and health, including how frequently they ate 50g bars of chocolate.
Participants were divided into quartiles according to their level of chocolate consumption. Follow-up questionnaires were sent to participants every 2-3 years until December 2006. This allowed data to be collected on the incidence of MI or stroke which was verified by access to medical records. Mortality data was verified by analysis of death certificates.
The top chocolate quartile, who ate approximately 7.5g/day, had systolic and diastolic blood pressure levels that were 1.0 mmHg (95% CI:-1.6 to -0.4) and 0.9 mmHg (95%CI: -1.3 to -0.5) lower than those in the bottom quartile, who consumed approximately 1.7g/day.
Over eight years of follow up there were 166 MIs (24 fatal) and 136 strokes (12 fatal). Those in the top chocolate quartile had a 27% reduced risk of MI and 48% reduced risk of stroke compared with those in the lowest quartile, relative risk of MI/stroke 0.61 (95% CI: 0.44-0.87, P=0.014). Baseline blood pressure accounted for 12% of this lower risk (95% CI: 3-36%). The association was stronger for stroke than MI.
I think we still need a randomised controlled trial of flavanol-rich chocolate but in the meantime it would seem that a little bit of chocolate is good for you. Don't get carried away though as those in the highest quartile only consumed 7.5g a day which is equivalent to a small square. A 100g bar has around 500 calories and a fair bit of that is sugar. So everything in moderation.
Dr Peter Savill