英語聽力文摘《記憶與糖》
以前常聽說心情與糖的關(guān)系，據(jù)說甜味會(huì)讓人快樂。那么，記憶與糖呢?這二者可存在什么關(guān)系?
Memory and Sugar
Sugar On The Brain
It’s long been understood that there is a connection between memory problems and diabetes, a disorder characterized by excessively high blood sugar. Sugar provides the body with fuel for various processes, including memory processing. In fact, glucose carried in the blood stream supplies the brain with 90 percent of the energy it requires to function properly.
In order to fuel those processes glucose has to get from the blood to the tissues, where it can be broken down and put to work. High blood sugar levels, such as in diabetes, are an indicator that a body is experiencing difficulty moving sugar from the blood to the tissues.
However, some non-diabetics have a less severe form of high blood sugar, a condition called impaired glucose tolerance. And it is this condition that seems to be the cause of memory problems in a significant number of non-diabetic elderly people who experience memory difficulties.
Sweet Nothings
Subjects were given glucose intravenously, and then researchers measured how quickly glucose moved from the blood to the tissues. Next the subjects were tested for overall cognitive functioning and the ability to recall short paragraphs. The results? Subjects who scored lowest on memory recall tests also showed impaired glucose tolerance.
In addition, brain scans demonstrated that these same subjects each had a significantly smaller hippocampus, a brain area important to learning and memory. The researchers hypothesize that impaired glucose tolerance may over time cause damage and atrophy to the hippocampus.
What can a body do to prevent this? A healthy diet and exercise can help maintain good glucose tolerance, perhaps preventing gradual memory decline.
記憶與糖
大腦中的糖
健忘與糖尿病有關(guān)，這個(gè)人們?cè)缇椭�。糖尿病是一種以血液中含糖量過高為特征的疾病。糖為身體的各項(xiàng)功能提供能量，其中就包括記憶功能。事實(shí)上，血液中的葡萄糖為腦部功能正常運(yùn)作提供了90%的能量。
為了給這些功能提供能量，葡萄糖必需從血液進(jìn)入到身體組織中，在那里葡萄糖得到分解并發(fā)揮效用。血液中含糖量太高，比如糖尿病就是這樣，表明身體在將糖從血液運(yùn)輸?shù)缴眢w組織時(shí)發(fā)生困難。
然而，一些非糖尿病患者，他們體內(nèi)含糖量高的病癥較輕微，這種病叫做葡萄糖耐受性受損。而廣大記憶產(chǎn)生障礙的老年非糖尿病患者會(huì)發(fā)生記憶衰退就是由該病導(dǎo)致。
"無用武之地"的糖
研究人員向?qū)嶒?yàn)對(duì)象進(jìn)行靜脈注射，然后測(cè)量葡萄糖從血液運(yùn)輸?shù)缴眢w組織中有多快。接下來，研究人員測(cè)驗(yàn)實(shí)驗(yàn)對(duì)象總體認(rèn)知功能及記憶短句的能力。結(jié)果如何?在記憶環(huán)節(jié)得分最低的`實(shí)驗(yàn)對(duì)象，同時(shí)也表現(xiàn)出葡萄糖耐受性受損的癥狀。
此外，大腦掃描表明患有該病的此類實(shí)驗(yàn)對(duì)象，大腦中對(duì)學(xué)習(xí)記憶非常重要的部位──海馬體，很明顯體積較小。研究人員猜測(cè)葡萄糖耐受性衰退可能長(zhǎng)期對(duì)海馬體造成傷害使其萎縮。
那么我們?cè)撊绾晤A(yù)防此類疾病呢?健康的飲食和進(jìn)行鍛煉有助于保持良好的葡萄糖耐受性，這也許可以防止記憶衰退。
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