People who eat chocolate regularly may not only be feeding their sweet tooth, but lowering their risk for heart disease, a new study suggests.
Chocolate has been linked to reducing the risk of heart disease before, but in this analysis of recent studies involving more than 100,000 people, researchers find that those who eat the most chocolate on a regular basis reduce their relative risk for heart disease by one-third.
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"At this point we are in the early stages of research," he added. There have not been any clinical trials to see if this association is real, Franco noted.
Chocolate might be beneficial but people should not consume it with the hope that it will reduce their risk of heart disease, Franco said. And if they do eat it, "because of the fat and sugar content, it should be consumed in moderation."
"If you are already eating chocolate, do it in moderation; if you are not eating chocolate, our advice is not to start eating chocolate," Franco said.
The report was published in the Aug. 29 online edition of the BMJ, to coincide with the presentation of the findings at the European Society of Cardiology Congress in Paris. The study did not receive funding from chocolate manufacturers.
For the study, Franco's team did a meta-analysis, which is a type of study where researchers comb the medical literature to find trends in relevant published studies.
In this case, the researchers identified seven studies that, combined, included 114,009 people.
When Franco's group pooled the data from these studies, they found that people who ate the most chocolate could reduce their risk of heart disease by as much as 37 percent, their risk of diabetes by 31 percent and their risk of stroke by 29 percent, compared with those who ate the least chocolate. Chocolate had no effect on heart failure risk, however.
It is not clear how much chocolate confers health benefits, Franco said. There was no way of telling how much chocolate was eaten by those who consumed the most of it, he explained. However, having chocolate regularly seemed to be important, he said.
These studies compared people who consumed chocolate more than once a week with those who ate it less often, Franco said.
"We still need to clarify the quantity that permits chocolate to prevent heart disease," he said. "Given the amount of sugar and calories in chocolate, we don't think it's going to be a high quantity."
In addition, since the chocolate eaten in these studies could have been dark, milk or even white chocolate, knowing which type is most beneficial is a question -- although Franco suspects dark chocolate will turn out to be the preferred type. "This is something we need to confirm," he said.
The study included consumption of chocolate bars, drinks, biscuits and desserts.
Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, commented that "despite chocolates indulgent reputation, there is growing evidence that cocoa products which contain high levels of flavonoids may have a variety of actions which are potentially beneficial for cardiovascular and metabolic health."
Several recent studies have suggested the flavonoids found in cocoa products have antioxidant, anti-inflammatory, anti-clotting effects and may also relax blood vessels, Fonarow said. He added that they may also improve insulin sensitivity, reducing the risk for diabetes.
However, the studies reviewed in this report were observational -- that is, they looked at data based on what people ate. Clinical trials, where chocolate is pitted against a placebo, are needed to see if the effect of chocolate is real, Fonarow said.
"Moderate consumption of dark chocolate may be a reasonable consideration as part of a heart health diet," he said. "However, as there is a complex interplay between nutrition and health, further studies are needed."
Nutrition expert Samantha Heller, a dietitian, nutritionist, exercise physiologist and clinical nutrition coordinator at the Center for Cancer Care at Griffin Hospital in Derby, Conn., added that "the cocoa bean contains healthy plant compounds like flavanols, called polyphenols, that act as powerful antioxidants and anti-inflammatory agents. [They may] help keep arteries healthy and may help lower blood pressure and cholesterol.
"But, and this is a big 'but,' people should not use this study as an excuse to chow down on candy bars, chocolate ice cream and chocolate cookies. This will pack on pounds and increase the risk of cardiovascular disease," Heller cautioned.
Fruits, vegetables and legumes also contain high amounts of polyphenols, along with fiber, vitamins, and minerals, Heller said. "So, enjoy some dark chocolate periodically and watch your portion size, but get the bulk of your polyphenols from fruits and vegetables."