Stroke Prevention: More Sweet News for Chocolate Lovers
WEDNESDAY Aug. 29, 2012 -- Eating moderate amounts of chocolate might reduce a man's risk of stroke in addition to its other reported benefits, a new Swedish study finds.
Researchers followed more than 37,000 men for more than 10 years, and found that those who ate the most chocolate had a 17 percent lower risk of stroke than those who never ate chocolate.
Flavonoids in chocolate have previously been linked with a reduced risk of heart disease and better mental performance. It's thought they may protect against cardiovascular disease through antioxidant, anti-clotting and anti-inflammatory factors, or by reducing cholesterol.
But neurologists aren't sending patients to the candy store based on this new report.
"You have to be very careful with these types of observational studies," said Dr. Richard Libman, vice chair of neurology at the Cushing Neuroscience Institute in Manhasset, N.Y.
While the research shows an association between chocolate consumption and stroke reduction, it does not show cause and effect. "There is no way to take from this study that chocolate causes a lower risk of stroke," Libman said.
The only way to prove whether or not chocolate reduces stroke risk is to do a randomized trial where some eat chocolate and others don't, he said. They would have to be followed for many years to see if chocolate made a difference, he added.
And eating too much chocolate can only add to the U.S. obesity epidemic and the health problems that go along with it, Libman noted.
For the report, published in the Aug. 29 online edition of Neurology, a team led by Susanna Larsson, from the Karolinska Institute in Stockholm, questioned men aged 49 to 75 about their diet and specifically how much chocolate they ate.
>Over the decade of follow-up, almost 2,000 men had a first stroke, they found. The risk was lower among those with greatest chocolate consumption, a median of about one-third of a cup of chocolate chips, or a little more than two ounces, a week.
A further analysis of five studies that included more than 4,200 stroke cases found those who ate the most chocolate reduced their risk of stroke 19 percent, compared with those who never ate chocolate, the researchers added. For every 50 grams of chocolate eaten a week -- about one-quarter cup of chocolate chips -- the risk of stroke declined by about 14 percent.
Benefits of chocolate have been associated with dark chocolate, but about 90 percent of the chocolate eaten in Sweden is milk chocolate, Larsson noted. Milk chocolate is fattier and contains less cocoa than dark chocolate.
Another expert agrees that chocolate, eaten in moderation, does appear to help the heart.
"There is a clear aggregation of research evidence indicating that chocolate, and in particular dark chocolate, confers a heart health benefit," said Dr. David Katz, director of the Prevention Research Center at Yale University School of Medicine in New Haven, Conn.
"Risk factors for heart disease and stroke are much the same, so it stands to reason that such benefit would extend to stroke," he said.
While the research doesn't prove cause and effect, "it's worth noting that this analysis carefully controls for many other factors, such as other important aspects of diet, including fruit and vegetable intake," he said. "The benefit of chocolate remains persuasive after accounting for such factors."
Because of chocolate's caloric, fat and sugar content, it is best thought of like red wine, where some is good but more isn't necessarily better, Katz said.
"Ongoing research will help establish the ideal 'dose' of chocolate for health benefits," he said. "In the interim, evidence favors the equivalent of roughly one ounce per day of chocolate with a cocoa content of 60 percent or higher."
Because chocolate consumption was self-reported and only at the start of the study, the researchers said more research is needed before recommendations are made.
Whether the new findings apply to women isn't clear. Four previous studies found an association between eating chocolate and reduced risk of stroke for women, or men and women combined, but the results for two of those studies weren't statistically significant.
For more information on stroke, visit the American Stroke Association.
Posted: August 2012