AsianScientist (Mar. 18, 2013) – A daily cup of green tea and coffee may help lower your risk of having a stroke, according to research published in Stroke: Journal of the American Heart Association.
“This is the first large-scale study to examine the combined effects of both green tea and coffee on stroke risks,” said Dr. Yoshihiro Kokubo, lead author of the study at Japan’s National Cerebral and Cardiovascular Center. “You may make a small but positive lifestyle change to help lower the risk of stroke by adding daily green tea to your diet.”
Researchers asked 83,269 Japanese adults about their green tea and coffee drinking habits, following them for an average 13 years.
Those who drank at least one cup of coffee daily had about a 20 percent lower risk of stroke compared to those who rarely drank it. Among those who preferred green tea, two to three cups a day led to a 14 percent lower risk of stroke and those who had at least four cups had a 20 percent lower risk, compared to those who rarely drank it.
Others who drank at least one cup of coffee or two cups of green tea daily had a 32 percent lower risk of intracerebral hemorrhage (internal bleeding in the brain), compared to those who rarely drank either beverage.
Participants in the study were 45 to 74 years old, almost evenly divided in gender, and were free from cancer and cardiovascular disease. During the 13 years of follow-up, researchers reviewed participants’ hospital medical records and death certificates, collecting data about heart disease, strokes and causes of death. They adjusted their findings to account for age, sex and lifestyle factors like smoking, alcohol, weight, diet and exercise.
Previous limited research has shown green tea’s link to lower death risks from heart disease, but not its association with lower stroke risks. Other studies have shown inconsistent connections between coffee and stroke risks.
Initial study results showed that drinking more than two cups of coffee daily was linked to increasing coronary heart disease rates in age- and sex-adjusted analysis. But after factoring in the effects of cigarette smoking — underscoring smoking’s negative health impact on heart and stroke health – the association with coronary heart disease could not be observed.
“The regular action of drinking tea, coffee, largely benefits cardiovascular health because it partly keeps blood clots from forming,” said Kokubo.
It’s unclear how green tea affects stroke risks. A compound group known as catechins may provide some protection. Catechins have an antioxidant anti-inflammatory effect, increasing plasma antioxidant capacity and anti-thrombogenic effects.
Green tea drinkers in the study were more likely to exercise compared to non-drinkers, the researchers found.
Some chemicals in coffee include chlorogenic acid, thus cutting stroke risks by lowering the chances of developing type 2 diabetes. Further research could clarify how the interaction between coffee and green tea might help further lower stroke risks, Kokubo said.
Source: AHA; Photo: bkajino/Flickr/CC.
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