When it comes to chocolate, order dark
种类不同功效差异大 吃黑巧克力好处多！
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http://www.100md.com 2005-3-24
chinadaily |
Natural yoghurt beats bad breath
Dark chocolate -- but not white chocolate - may help reduce blood pressure and boost the body's ability to metabolize sugar from food, according to the results of a small study.
Investigators from the University of L'Aquila in Italy found that after eating only 100 grams, or 3.5 ounces, of dark chocolate every day for 15 days, 15 healthy people had lower blood pressures and were more sensitive to insulin, an important factor in metabolizing sugar.
In contrast, eating roughly the same amount of white chocolate for the same period of time did not affect either blood pressure or insulin sensitivity.
This is not the first study to demonstrate potential health benefits of dark chocolate, which contains high levels of a kind of antioxidant called flavonoids. Research shows that flavonoids that can help maintain a healthy heart and good circulation and reduce blood clotting, which can lead to heart attacks and stroke.
Dr. Claudio Ferri and co-investigators explained that flavonoids help the body by neutralizing potentially cell-damaging substances known as oxygen-free radicals, which are a normal byproduct of metabolism.
However, despite dark chocolate's apparent benefits, Ferri urges caution when interpreting the results. Dark chocolate contains antioxidants, but also a lot of fat and calories, Ferri said, and people who want to add some chocolate to their diet need to subtract an equivalent amount of calories by cutting back on other foods, to avoid weight gain.
He added that each 100 grams of dark chocolate contains roughly 500 calories.
Other research validates that when it comes to chocolate, type does matter. One study found that eating milk chocolate did little to raise antioxidant levels in the blood, perhaps because milk interferes with the absorption of antioxidants from chocolate.
Another study showed that elderly people with high blood pressure experienced a drop in pressure after eating dark chocolate bars, but not white chocolate, which contains no flavonoids.
Ferri and colleagues asked 7 men and 8 women, all healthy, to eat 100 grams of dark chocolate or 90 grams of white chocolate every day for 15 days. The subjects consumed no chocolate for the next 7 days and then switched to the other chocolate type for 15 days.
"The identification of healthy foods and the understanding of how food components influence normal physiology will help to improve the health of the population," Dr. Cesar G. Fraga of the University of California, Davis, notes in an editorial.
(Agencies)
一项小规模研究的结果表明，黑巧克力可能有助于降低血压、促进人体对食物中的糖分的代谢能力，而白巧克力则没有这些功能。
意大利拉奎拉大学的调查者们发现，在连续15天每日食用100克或3.5盎司黑巧克力之后，15名健康的受试者的血压有所降低，而且对胰岛素更为敏感--胰岛素是促进体内糖分代谢的重要成分。
相比之下，同样在15天中食用大致相同数量的白巧克力对血压和胰岛素的敏感性并没有影响。
这已经不是有关黑巧克力可能有益健康的第一项研究。黑巧克力富含一种叫作类黄酮的抗氧化剂，研究表明类黄酮有助于保持心脏的健康和血液循环的畅通，并减少可能导致心脏病和中风的血栓。
克劳迪奥·费里教授与他的合作者们解释说，类黄酮能抑制对细胞有破坏能力的氧自由基(新陈代谢的副产品)的产生，从而有利于人体健康。
然而，尽管黑巧克力具有以上种种显而易见的好处，费里教授在解释研究结果时还是劝告人们提高警惕，他说，黑巧克力含有抗氧化剂，但也含有大量脂肪和卡路里，因此希望在饮食中添加巧克力的人们需要从其他食物中“扣除”等量的卡路里，以免体重增加。
他补充说，每100克黑巧克力包含大约500卡路里。
其他的研究也证实了不同种类的巧克力确实功效不同。一项研究表明食用牛奶巧克力并不能增加血液中的抗氧化剂，这也许是因为牛奶阻碍了巧克力中的抗氧化剂的吸收。
另一项研究结果表明，患有高血压的老人在吃了黑巧克力棒后血压下降，但是不含类黄酮的白巧克力则没有这个功效。
费里教授和他的同事们找了七名健康的男性和八名健康的女性，让他们连续15天每天食用100克黑巧克力或90克白巧克力。受试者们在随后的七天内没有吃任何巧克力，然后在接下来的15天内转而吃另一种巧克力(白巧克力或黑巧克力)。
“对健康食物的定义以及对食物成分如何影响正常生理功能的理解，将有助于改善人口的健康状况。”加里佛尼亚大学戴维斯分校的恺撒·G·弗拉革博士在一篇评论中写道。
(中国日报网站译)
Vocabulary:
metabolize: to subject (a substance) to metabolism(使新陈代谢，产生代谢变化)
insulin: a polypeptide hormone secreted by the islets of Langerhans and functioning in the regulation of the metabolism of carbohydrates and fats, especially the conversion of glucose to glycogen, which lowers the blood glucose level(胰岛素，一种胰岛分泌的多肽激素，作用于碳水化合物和脂肪新陈代谢的调节系统，特别作用于葡萄糖向降低血糖的糖原转化的过程)
antioxidant: a chemical compound or substance that inhibits oxidation(抗氧化剂，阻氧化剂)
neutralize: to counterbalance or counteract the effect of; render ineffective.
(使无效，抵消，使中和)
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