Eating chocolate may have heart benefits

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Consuming chocolate could substantially reduce the risk for cardiometabolic disorders, results of a recently published meta-analysis suggest.

Participants in six studies who ate about two pieces of chocolate a week had a 37% lower risk for cardiovascular disease compared with those who at less (RR=0.63; 95% CI: 0.44-0.90), Oscar H. Franco, PhD, of the University of Cambridge in England, and colleagues wrote in BMJ.

Stroke risk was also 29% lower among those who ate the most chocolate in three studies (RR=0.71; 95% CI: 0.52-0.98), the researchers determined.

“Based on observational evidence, levels of chocolate consumption seem to be associated with a substantial reduction in the risk of cardiometabolic disorders,” the researchers wrote. However, they added that further research is necessary to establish causation before any dietary recommendations can be made.

Additionally, most commercially available forms of chocolate are high in sugar and fat, the researchers emphasized, warning that consuming excessive amounts could negate chocolate's potential benefits.

Previous studies have documented a number of heart healthy properties in chocolate — particularly the dark variant — including antioxidant, antihypertensive, anti-inflammatory, anti-atherogenic and anti-thrombotic effects.

To further examine these relationships, Franco and colleagues examined data from seven studies that included 114,009 participants from the United States, Japan, The Netherlands, Sweden and Germany. Six of the studies were observational; one was cross-sectional and none reported industry funding.

Study participants reported general chocolate consumption and did not differentiate between the type of chocolate and whether it was dark or another form.

Because measurement units varied from study to study, the researchers decided to stratify participants into high consumption and low consumption groups with a cut-off point of two pieces of chocolate per week. The size of a piece of chocolate could not be defined using the available data.

Among the six studies that had cardiovascular outcomes, all reported a lower risk for cardiovascular disease among people who consumed the most chocolate. Although risk reduction was significant in only three studies, a pooled analysis yielded statistically significant results.

Of the three studies in which stroke was an outcome, data from one study indicated significant risk reduction, whereas data from the other two were not statistically significant. When the researchers performed a pooled analysis the overall results were significant in support of reducing stroke risk.

An association between chocolate consumption and heart failure was not observed in the two studies in which heart failure was an outcome.

Although the direct mechanisms by which chocolate mediates heart-health remain unknown, the researchers propose that high polyphenol levels may play a role.

“Considering the limited data available, any conclusions should be cautious,” the researchers noted. They called for more studies to corroborate the findings, as well as efforts to assess the effect of different chocolate types and standardize consumption measurements.

Buitrago-Lopez A et al. BMJ. 2011; doi:10.1136/bmj.d4488.

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