提到巧克力，大家的第一印象往往是会使人发胖。但是有科学实验证明适当的食用黑巧克力有助于保护心脑血管，这是为什么呢?答案请到下面的阅读材料中寻找吧!
适当的食用黑巧克力能达到保护心血管健康的作用，这是为什么呢?今天的托福考试阅读练习材料就将告诉你答案。
Dark chocolate has been shown to have a beneficial effect on the heart in numerous studies, and now scientists from Linkoping University in Sweden know why.
经过数次科学实验，黑巧克力已被证明为“护心”食品。而如今，瑞典林雪平大学的科学家们发现了黑巧克力的“护心”奥秘。
Because they found snacking on a slab of the cocoa-rich treat inhibits an enzyme in the body that is known to raise blood pressure.
原来，一小块可可含量高的甜点便会抑制一种酶的活性，而这种酶正是让血压升高的“元凶”。
Researchers recruited 16 healthy non-smoking volunteers for the study. Two days before the study they were not allowed to eat chocolate or anything containing similar compounds, including many berries, nor could they drink coffee, tea, or wine. Everyone in the group gave a blood sample both before and after eating 75 grams of unsweetened chocolate with a cocoa content of 72 percent.
研究人员们招募了16名志愿者，他们均不吸烟。在实验开始的两天前，这些志愿者不得吃巧克力以及任何含有相似成分的食物(包括各种浆果)，也不能喝咖啡、茶或者酒类。实验开始，每个人进行了血液样本检测，然后服用75克无糖巧克力(可可含量达72%)，随后再进行一次血液样本检测。
Scientists found ACE enzyme activity was reduced by 18 percent three hours after the cocoa dose. This is comparable to the effect of drugs that inhibit ACE and are used as a first-choice treatment for high blood pressure.
科学家们发现，一种叫做血管紧张素转换酶的酶类活性在志愿者服用可可三小时后降低了18%。这样的效果几乎可与此前抑制血管紧张素转换酶活性、并用来治疗高血压的首选药物效果相匹敌。
Drug researcher Ms. Persson said: "Our findings indicate that changes in lifestyle with the help of foods that contain large concentrations of catechins and procyaninides prevent cardiovascular diseases."
药物研究人员帕森女士称：“这些发现表明了，食用含有高浓度儿茶酚及前花青素的食物有助于人们远离降低心血管疾病。”
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