A few cups of green tea each day may help prevent heart disease, Greek researchers said on Wednesday.

A study published in the European Journal of Cardiovascular Prevention and Rehabilitation¹ showed further evidence of the potential health benefits from a brew² already linked to a reduced risk of a range of cancers and other conditions.

The study showed that green tea improves blood flow and the ability of arteries³ to relax, said Charalambos Vlachopoulos, a cardiologist at the Athens Medical School in Greece who worked on the study.

Other studies have shown that black tea also has benefits for cardiovascular health.

The Greek team said they believed green tea might be even better because it had higher quantities of beneficial compounds called flavonoids -- some of which are lost in the oxidation process that black tea undergoes.

Flavonoids are also found in cocoa, tomatoes and grapes.

"A couple of cups a day would probably be a good dose for people," Vlachopoulos said. "This is the first study to show these effects for green tea."

The researchers gave 14 healthy volunteers either green tea, diluted⁴ caffeine or hot water and then measured the function of endothelial cells lining⁵ the circulatory system.

These cells help relax arteries and ease blood flow.

"What is important is these effects are evident fairly rapidly, within 30 minutes," Vlachopoulos said.

The measurements taken 30, 90 and 120 minutes following consumption showed an almost immediate⁶ benefit among people who had drunk green tea, he said.

While the researchers looked only at a short-term impact, Vlachopolous said the team's studies suggest the protection is long lasting⁷.

"Green tea is consumed less in the Western world than black tea, but it could be more beneficial because of the way it seems to improve (circulatory) function," he said.

希腊研究人员于本周三称，每天喝几杯绿茶有助于预防心脏病。

在《欧洲心血管病预防与恢复期刊》上发表的一项研究显示，有更多的证据已证明绿茶具有潜在的保健功效，能够降低患癌症及其他疾病的风险。

从事该研究的希腊雅典医学院心脏病学家卡拉兰波斯•维拉科珀罗斯说，研究发现绿茶能够促进血液流动，并能增强动脉疏通能力。

此前已有研究表明红茶对心血管健康也有好处。

希腊的这一研究小组称，他们认为绿茶的心血管保健功效可能会更强，因为绿茶中所含的一种名叫“类黄酮”的有益物质较多，而这种物质在红茶氧化过程中会部分流失。

可可、西红柿和葡萄中也含有类黄酮。

维拉科珀罗斯说：“每天喝几杯绿茶可能最益于健康。这是第一个表明绿茶具有心血管保健功效的研究。”

研究人员让14名身体健康的志愿者分别饮用绿茶、稀释的咖啡和热水，然后对他们的循环系统内皮细胞的机能进行检测。

内皮细胞有助于疏通动脉，促进血液循环。

维拉科珀罗斯说：“关键是效果很快就显现出来了，30分钟内就见效。”

他说，对喝了绿茶的研究对象在饮茶30分钟、90分钟及120分钟后的检测结果显示，绿茶的功效可谓“立竿见影”。

尽管研究人员只探究了绿茶的短期功效，但维拉科珀罗斯称，他们的研究表明，这种保护功效是长期的。

他说：“在西方国家，人们喝红茶多于绿茶。但由于绿茶具有促进血液循环的功能，所以喝绿茶可能更有益于健康。”