医疗英语：常喝绿茶和咖啡可降中风风险

Green tea and coffee may help lower the risk of stroke, especially when both are taken as a regular part of the diet, according to a research published on Thursday 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 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 span of 13 years. They found that the more green tea or coffee people drink, the lower their stroke risks.

People 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. People who drank two to three cups of green tea daily had 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.

And people who drank at least one cup of coffee or two cups of green tea daily had a 32-percent lower risk of intracerebral hemorrhage, compared to those who rarely drank either beverage.

Intracerebral hemorrhage happens when a blood vessel bursts and bleeds inside the brain. About 13 percent of strokes are hemorrhagic.

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 the 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.

Tea and coffee are the most popular drinks in the world after water, which suggests that these results may also apply in America and other countries, the researchers said.

It's unclear how green tea affects stroke risks. A compound group known as catechins may provide some protection, according to the researchers.

Catechins have an antioxidant anti-inflammatory effect, increasing plasma antioxidant capacity and anti-thrombogenic effects.

相关新闻：美国心脏病协会主办的期刊《中风》14日刊登论文称，日本研究人员的调查显示常喝绿茶和咖啡的人出现中风的风险更低，如果日常生活中两种饮品都经常饮用，降低中风风险的效果则更佳。

日本国立大脑和心血管中心的研究人员对8万多名年龄在45岁至74岁的成年人进行了为期13年的随访，并记录他们的饮食习惯。研究开始时，这些人中没有癌症或心血管病患者。随访期间，研究人员通过分析他们的医疗记录，收集心脏病、中风及死因等方面的数据。

分析显示，即使在考虑年龄、性别、生活方式等因素后，常喝绿茶和咖啡也与中风风险下降存在关联。与几乎不喝绿茶或咖啡者相比，每天饮用两到三杯绿茶者出现中风的风险低14%，每天至少喝一杯咖啡者出现中风的风险低20%。此外，后两部分人群出现脑溢血的风险也要低32%。

研究人员表示，常饮绿茶或咖啡降低中风风险的原因目前还不清楚，不过绿茶内的成分儿茶素具有抗氧化、消炎等功能，咖啡内的绿原酸具有抗氧化、抗菌等功能，它们可能发挥了作用。研究人员认为，茶和咖啡在世界范围内都是很常见的饮品，这意味着它们在降低中风风险方面的好处容易推广。