Even better, the more chocolate women indulged in, the lower their stroke risk, Swedish researchers found. For every 50-gram (1.8-oz.) increase in chocolate consumption per week, participants’ overall stroke risk dropped 14%. The protective effect appeared to kick in at 45 g (1.6 oz.) of chocolate a week, with women in the highest consumption group — who ate a median of 66.5 g (2.4 oz.), or between one and two chocolate bars a week — enjoying a 20% lower risk of stroke than those who ate the least.
When broken down by type of stroke — ischemic, which occurs when a blood vessel supplying blood to the brain is blocked by a clot, versus hemorrhagic, which occurs when a blood vessel in the brain weakens and bursts — the protective benefits of chocolate varied. Each 50-gram-per-week increase in chocolate consumption was associated with a 27% drop in hemorrhagic stroke risk, compared with a 12% lower risk of strokes caused by clots. Why the effect was greater with one type of stroke wasn’t clear, the authors wrote.
Led by Susanna Larsson, an associate professor in the division of nutritional epidemiology at the Karolinska Institute in Stockholm, researchers tracked 33,372 women aged 49 to 83 for about 10 years, until 2008. At the start of the study, the women filled out lengthy questionnaires about their diet and lifestyle, including how often they had eaten chocolate and about 95 other foods in the previous year.
Over the next decade, researchers recorded 1,549 strokes, including 1,200 ischemic strokes, 224 hemorrhagic strokes and 125 that weren’t specified. The protective effect of chocolate consumption on women’s stroke risk persisted, even after researchers adjusted for other major stroke risk factors. The findings fall in line with past research on the topic.
The potential health benefits of chocolate, especially dark chocolate, have been widely attributed to its flavonoids, antioxidant compounds in cocoa that may boost the cardiovascular system. In other studies, researchers have shown that flavonoids can enhance blood flow by relaxing blood vessels and lowering blood pressure. They may also inhibit clumping of platelets and reduce inflammation, both of which contribute to cardiovascular health.
The question is, Do women start gorging on chocolate to protect themselves from stroke? Not exactly. For one thing, chocolate is decadent and is meant to be eaten in moderation. “Consuming too much chocolate is probably not good, as chocolate is rich in sugar, fat and calories, and may lead to weight gain, which increases the risk of chronic diseases,” says Larsson.
Chocolate isn’t the only food that contains antioxidants, of course. “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,” Dr. Nieca Goldberg, a cardiologist at NYU Langone Medical Center in New York City, told HealthDay. “Chocolate does have antioxidants, and antioxidants are beneficial for your health. … But, what if they had tried this study with apple skins or grapes?”
While the study adds to the evidence that chocolate may be good for cardiovascular health, its observational nature can’t prove a direct effect. Its reliance on women’s self-reports of diet and lifestyle further limits its findings.
The authors also note that 90% of the chocolate consumed in Sweden at the time of the questionnaire was Swedish milk chocolate, which contains about 30% cocoa solids — a much higher concentration than what Americans are used to eating. So if you’re going to pick up a chocolate bar, the author suggests choosing dark chocolate, at least 70% cocoa, which has more antioxidants and less sugar than milk chocolate.
“Chocolate consumption in moderation, and preferably dark chocolate, along with high consumption of other antioxidant-rich foods such as fruits and vegetables may help reduce the risk of stroke,” Larsson says.
The study was published as a research letter in the Journal of the American College of Cardiology.