Eating chocolate linked to reduced CVD risk
MedWire News: Eating chocolate may reduce risk for cardiovascular disease (CVD), partly as a result of its blood-pressure lowering effect, an observational study suggests.
The findings are no excuse for binging on Easter eggs though – the amounts of chocolate consumed were relatively small, and researchers emphasized that people should not increase their overall intake of calories or replace healthy foods in their diet with chocolate.
The study of nearly 20,000 adults, published in the European Heart Journal, found that those who ate the most chocolate had roughly a 40% lower relative risk for myocardial infarction (MI) or stroke than those who ate the least; the difference in their daily intake was 6 g – less than one square of an average chocolate bar.
Lead researcher Brian Buijsse remarked: “In terms of absolute risk, if people in the group eating the least amount of chocolate… increased their chocolate intake by 6 g per day, 85 fewer heart attacks and stroke per 10,000 people could be expected over a period of about 10 years.”
Based on this risk reduction, the number of avoidable events could be even higher in the general population, he added.
Buijsse and team, from the German Institute of Human Nutrition in Nuthetal, followed 19,357 participants of the Potsdam arm of the EPIC (European Prospective Investigation into Cancer) study, aged 35–65 years, for a median of 8.3 years.
Blood pressure and usual food intake, based on a self-administered food-frequency questionnaire, were assessed at baseline. To assess chocolate consumption, participants were asked how often they ate a 50-g bar, and could indicate if they consumed half a bar, one, two, or three bars.
After adjusting for age, gender, lifestyle factors, anthropometrics, dietary factors, and the prevalence of diabetes, the relative risk for the combined endpoint of MI and stroke was 0.41 for the top (average 7.5 g per day) versus bottom (1.7 g per day) quartile of chocolate consumption. The association was stronger for stroke, at a relative risk of 0.52, while that for MI alone was statistically non-significant, at 0.73.
Baseline blood pressure was also inversely associated with chocolate intake, but only explained 10–16% of these relative risk reductions. Other benefits of chocolate, which are thought to relate to the flavanol and therefore cocoa content, on the endothelium and platelet function could also contribute to the lower CVD risk, the authors note.
A subpopulation analysis revealed that most (57%) of the participants reported that they ate milk rather than dark (24%) chocolate, which the authors say could explain why the effect of chocolate intake on blood pressure observed was weaker than in previous studies.
Buijsse and colleagues conclude: “Given these and other promising health effects of cocoa, it is tempting to indulge more in chocolate. Small amounts of chocolate, however, may become part of a diet aimed to prevent CVD only after confirmation by other observational studies and particularly by randomized trials.”
Commenting on behalf of the European Society of Cardiology, Frank Ruschitzka (University Hospital, Zurich, Switzerland) said: “Basic science has demonstrated quite convincingly that dark chocolate particularly, with a cocoa content of at least 70%, reduces oxidative stress and improves vascular and platelet function.”
However, before rushing to eat more dark chocolate people should be aware that 100 g of dark chocolate contains roughly 500 calories, he added. Subtracting an equivalent amount of calories to the amount consumed in chocolate by cutting back on other foods is therefore necessary to avoid weight gain, said Ruschitzka.
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By Caroline Price