First author Susanna C. Larsson, of the Karolinska Institute in Stockholm, told the media:
"While other studies have looked at how chocolate may help cardiovascular health, this is the first of its kind study to find that chocolate, may be beneficial for reducing stroke in men."
Earlier this year, researchers from the University of California, San Diego also reported finding that regular chocolate eaters tend to be thinner.
For this latest study, Larsson and colleagues undertook two pieces of research: a large prospective study of Swedish men, and a meta-analysis of already published studies.
Cohort of Swedish MenIn the first piece of research, a prospective investigation of a large group over 10 years, the team looked at questionnaire responses from 37,103 Swedish men aged 49 to 75 taking part in the Cohort of Swedish Men. The questionnaires had asked the men how often they consumed various foods and drinks, including chocolate.
Then, using the Swedish Hospital Discharge Registry, the researchers identified 1,995 cases of first stroke among the men during the 10 years following their questionnaire assessment. The stroke cases included 1,511 cerebral infarctions, 321 hemorrhagic strokes, and 163 unspecified strokes.
Flavonoids found in chocolate may decrease blood concentrations of bad cholesterol and reduce blood pressure.
Meta-AnalysisIn the second piece of research, the team pooled data from five studies that included 4,260 cases of stroke and information on chocolate consumption.
The analysis revealed those who ate the most chocolate had a 19% lower risk for stroke than non-chocolate consumers.
It also found a dose-response relationship, where for every extra 50 gms of chocolate consumed per week (about a quarter of a cup of chocolate chips), there was a fall in stroke risk of about 14%.
Flavonoids in ChocolateSpeculating on what it is about chocolate that may account for this effect on stroke risk, Larsson suggests it may be something to do with the flavonoids it contains.
Flavonoids, a group of polyphenolic compounds known to have beneficial biochemical and antioxidant effects, appear to protect against cardiovascular disease through antioxidant, anti-clotting and anti-inflammatory properties, says Larsson.
"It's also possible that flavonoids in chocolate may decrease blood concentrations of bad cholesterol and reduce blood pressure," she adds.
Many researchers maintain it is dark chocolate that is good for the heart, but Larsson says surprisingly:
"... about 90 percent of the chocolate intake in Sweden, including what was consumed during our study, is milk chocolate."
Funds from the Swedish Council for Working Life and Social Research, the Swedish Research Council/Committee for Infrastructure and the Karolinska Institute, helped pay for the study.