October 11, 2011
New Evidence That Chocolate Lowers Stroke Risk
Chocolate lovers may have a new reason to celebrate: A Swedish study suggests that women who have a couple of small chocolate bars every week are 20 percent less likely to suffer debilitating strokes than those who abstain from eating chocolate.
The study, published this week in the Journal of the American College of Cardiology, looked at more than 33,000 women and found that the more chocolate they ate, the lower their risk of stroke. This finding adds to the strong evidence that links cocoa consumption to heart health, but it doesn´t mean people have a free pass to gorge on chocolate.“Given the observational design of the study, findings of this study cannot prove that it's chocolate that lowers the risk of stroke,” Susanna Larsson, from Karolinska Institutet in Stockholm, told Reuters Health by email.
While she believes that chocolate does have health benefits, she has also warned that eating too much chocolate could be counterproductive. “Chocolate should be consumed in moderation as it is high in calories, fat and sugar. As dark chocolate contains more cocoa and less sugar than milk chocolate, consumption of dark chocolate would be more beneficial,” she said.
Larsson and colleagues analyzed data from a mammography study that included self-reports of how much chocolate women ate in 1997. The ages of the women ranged from 49 to 83 years. None of the women had any history of stroke, heart disease, cancer or diabetes when the study began.
The women were asked to complete a questionnaire that included questions on more than 350 diet and lifestyle factors.
Researchers reviewed the questionnaires and then grouped the women by frequency of their chocolate consumption, ranging from never to more than three times a day and looked for associations between strokes and the amount of chocolate the women regularly consumed.
During the 10-year study, 1,549 of the more than 33,000 women suffered a stroke. Most -- around 1,200 -- had an ischemic stroke. That means a blood vessel in the brain is blocked, starving an area of the brain of blood and oxygen. Another 224 had hemorrhagic strokes, which means an area of the brain is bleeding into the rest of the brain. The remaining 125 were unspecified.
Among those with the highest weekly chocolate intake, more than 45 grams, there were 2.5 strokes per 1,000 women per year. That figure was 7.8 per 1,000 among women who at the least, less than 8.9 grams a week.
“We observed that women with the highest consumption of chocolate [an average of about 2.3 ounces per week] had a significant 20 percent lower risk [of stroke] than those who never or rarely consumed chocolate,” said Larsson.
Larsson believes the results seen in women would be similar in men. And although US chocolate generally contains less cocoa than chocolate in Europe, there should be a benefit from consumption in that country as well. But suggested that “chocolate should preferably be consumed as dark chocolate, as it contains more of the beneficial flavonoids, as well as less sugar.”
About 90 percent of the chocolate consumed in Sweden in the 1990s was milk chocolate that contained about 30 percent cocoa solids. This is a much higher concentration of cocoa than what is found in most dark chocolate products sold in the United States.
“Cocoa contains flavonoids, which have antioxidant properties and can suppress oxidation of low-density lipoprotein [℠bad´ cholesterol] which can cause cardiovascular disease [including stroke],” explained Larsson.
“There's an upside and a downside to everything. I don't think people should eat all the chocolate they can, but some chocolate in moderation can have some benefit,” Dr. Nieca Goldberg, a cardiologist and medical director of the Joan H. Tisch Center for Women's Health at NYU Langone Medical Center in New York City, told HealthDay reporter Serena Gordon.
Dark chocolate has been found to reduce blood pressure, lower insulin resistance and help keep your blood from forming dangerous clots, Larsson added.
However, it´s important to remember that chocolate has a lot of sugar and fat, and also contains caffeine, Goldberg noted. So, if you are prone to irregular heartbeat or high blood pressure, eating chocolate may affect those conditions as well.
“It's important to keep findings like these in context. These findings don't mean that people need to exchange chocolate for broccoli in their diet,” said Goldberg. “Chocolate does have antioxidants, and antioxidants are beneficial for your health. They can help make your arteries more flexible and they can help you resist the oxidation of cholesterol. But, what if they had tried this study with apple skins or grapes?” she said.
Larsson suggested that Americans stick with dark chocolate, but noted that US chocolate bars need only contain 15 percent cocoa to be called sweet dark chocolate. Dark chocolate typically is lower in sugar than milk chocolate and contains more of the important antioxidants that give cocoa its heart-healthy properties.
One drawback of the study was that it was based on people´s self-reports of what they ate, and self-reports are typically unreliable. Larsson said, like all other research into the health benefits of chocolate, there needs to be further research to confirm the findings seen in her study.
In late August, researchers announced at the European Society of Cardiology 2011 that a meta-analysis of previous studies found people who ate the most chocolate had a 37 percent lower risk of cardiovascular disease and a 29 percent lower risk of stroke than those who ate the least chocolate.
Nearly 800,000 people suffer a stroke each year in the US, with about 17 percent of them dying of it and many more left disabled. For those at high risk, doctors recommend blood pressure medicine, quitting smoking, exercising more and eating a healthier diet.
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