VOA标准英语2010年-Ginkgo Biloba Ineffective in Preventin

Practitioners¹ of alternative medicine have recommended ginkgo biloba as a means of maintaining and even improving memory among older adults. But until now, strong clinical evidence about its effectiveness has not been forthcoming.

For eight years, researchers at six universities across the U.S. studied more than three thousand adults, aged² 72 to 96, with normal mental functioning or with mild cognitive³ impairment. Participants received either a 120-mg dose of gingko extract twice a day, or a sugar pill. Researchers found that gingko had no specific effect on memory or attention.

"What we can say is that we find no evidence that ginkgo, over this long period of time made a difference in whether someone's slow change in memory function, as a function of normal aging, was affected⁴ at all by the medication," said Dr. Steven Dekosky, at the University Of Virginia.

Earlier research showed that gingko did nothing for people with symptoms of Alzheimer's disease, nor did it help reduce other forms of dementia.

Researchers say this latest study is notable because it was conducted with the largest number of participants, and it rules out the herbal supplement as a useful treatment for memory loss.

"We found that there was no effect of the ginkgo biloba on these very slow but, clearly detectable⁵ changes in thinking function in late life," added Dr. Steven Dekosky.

But the researchers added one caveat⁶: While gingko biloba is not effective in slowing down the mental changes of aging, they say it is safe and has no side effects.

1 practitioners   

n.习艺者，实习者( practitioner的名词复数 )；从业者（尤指医师）

参考例句：

• one of the greatest practitioners of science fiction 最了不起的科幻小说家之一
• The technique is experimental, but the list of its practitioners is growing. 这种技术是试验性的，但是采用它的人正在增加。 来自辞典例句

2 aged   

adj.年老的，陈年的

参考例句：

• He had put on weight and aged a little.他胖了，也老点了。
• He is aged,but his memory is still good.他已年老，然而记忆力还好。

3 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

4 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

5 detectable   

adj.可发觉的；可查明的

参考例句：

• The noise is barely detectable by the human ear.人的耳朵几乎是察觉不到这种噪音的。
• The inflection point at this PH is barely detectable.在此PH值下，拐点不易发现。

6 caveat   

n.警告； 防止误解的说明

参考例句：

• I would offer a caveat for those who want to join me in the dual calling.为防止发生误解，我想对那些想要步我后尘的人提出警告。
• As I have written before,that's quite a caveat.正如我以前所写，那确实是个警告。