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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) |
一項(xiàng)小規(guī)模研究的結(jié)果表明，黑巧克力可能有助于降低血壓、促進(jìn)人體對(duì)食物中的糖分的代謝能力，而白巧克力則沒有這些功能。
意大利拉奎拉大學(xué)的調(diào)查者們發(fā)現(xiàn)，在連續(xù)15天每日食用100克或3.5盎司黑巧克力之后，15名健康的受試者的血壓有所降低，而且對(duì)胰島素更為敏感--胰島素是促進(jìn)體內(nèi)糖分代謝的重要成分。
相比之下，同樣在15天中食用大致相同數(shù)量的白巧克力對(duì)血壓和胰島素的敏感性并沒有影響。
這已經(jīng)不是有關(guān)黑巧克力可能有益健康的第一項(xiàng)研究。黑巧克力富含一種叫作類黃酮的抗氧化劑，研究表明類黃酮有助于保持心臟的健康和血液循環(huán)的暢通，并減少可能導(dǎo)致心臟病和中風(fēng)的血栓。
克勞迪奧·費(fèi)里教授與他的合作者們解釋說，類黃酮能抑制對(duì)細(xì)胞有破壞能力的氧自由基（新陳代謝的副產(chǎn)品）的產(chǎn)生，從而有利于人體健康。
然而，盡管黑巧克力具有以上種種顯而易見的好處，費(fèi)里教授在解釋研究結(jié)果時(shí)還是勸告人們提高警惕，他說，黑巧克力含有抗氧化劑，但也含有大量脂肪和卡路里，因此希望在飲食中添加巧克力的人們需要從其他食物中“扣除”等量的卡路里，以免體重增加。
他補(bǔ)充說，每100克黑巧克力包含大約500卡路里。
其他的研究也證實(shí)了不同種類的巧克力確實(shí)功效不同。一項(xiàng)研究表明食用牛奶巧克力并不能增加血液中的抗氧化劑，這也許是因?yàn)榕Ｄ套璧K了巧克力中的抗氧化劑的吸收。
另一項(xiàng)研究結(jié)果表明，患有高血壓的老人在吃了黑巧克力棒后血壓下降，但是不含類黃酮的白巧克力則沒有這個(gè)功效。
費(fèi)里教授和他的同事們找了七名健康的男性和八名健康的女性，讓他們連續(xù)15天每天食用100克黑巧克力或90克白巧克力。受試者們?cè)陔S后的七天內(nèi)沒有吃任何巧克力，然后在接下來的15天內(nèi)轉(zhuǎn)而吃另一種巧克力（白巧克力或黑巧克力）。
“對(duì)健康食物的定義以及對(duì)食物成分如何影響正常生理功能的理解，將有助于改善人口的健康狀況。”加里佛尼亞大學(xué)戴維斯分校的愷撒·G·弗拉革博士在一篇評(píng)論中寫道。
（中國日?qǐng)?bào)網(wǎng)站譯） |
Updated: 2005-03-24 10:12