托福阅读材料(196)：瘦下来吧 肥胖的人更易患痴呆

　　托福阅读材料/知识之肥胖的人更易患痴呆，更多托福阅读背景材料/知识尽在新东方在线托福考试频道！

　　一般来说，我们都知道肥胖的人体型不美观，还有可能有一些血脂和血压方面的问题，但是，我们大概不知道，肥胖的人比一般人更容易患痴呆。

　　最新一项研究显示，肥胖会加速人的认知能力衰退，从而增加患痴呆症的风险。这项研究对6000多名年龄在35到55岁的英国公务员进行了为期十年的跟踪调查，并且在十年期间对他们进行了三次记忆力和认知技能测试。结果显示，身体肥胖且伴有不健康代谢变化的被试者认知技能退化速度比其他人要快。不过，专家强调，该研究关注的知识被试人群的认知功能，而不是痴呆症。正常老化、轻微认知障碍以及痴呆症之间的界限很模糊，但并不是所有的认知障碍都会导致痴呆症。研究人员表示，目前还不清楚为何肥胖和代谢异常与大脑功能退化相关，不过怀疑可能与高血糖及高胆固醇等因素有关。

　　Being overweight is not just bad for waistlines but for brains too, say researchers who have linked obesity to declining mental performance.

　　Being overweight is not just bad for waistlines but for brains too, say researchers who have linked obesity to declining mental performance.

　　Experts are not sure why this might be, but say metabolic changes such as high blood sugar and raised cholesterol are likely to be involved.

　　Obesity has already been tipped as a risk factor for dementia.

　　The work, published in Neurology, tracked the health of more than 6,000 British people over a decade.

　　The participants, who were aged between 35 and 55, took tests on memory and other cognitive skills three times over a 10-year period.

　　People who were both obese and who had unhealthy metabolic changes showed a much faster decline on their cognitive test scores compared to others in the study.

　　Delving deeper

　　The experts stress that they only looked at cognitive function, not dementia.

　　The boundary between normal ageing, mild cognitive impairment and dementia is blurred - not all impairment leads to dementia.

　　All of the study participants came from one group of civil service workers, which may mean the findings may not apply more generally to other populations.

　　They said: "More research is needed to look at the effects of genetic factors and also to take into account how long people have been obese and how long they have had these metabolic risk factors and also to look at cognitive test scores spanning adulthood to give us a better understanding of the link between obesity and cognitive function, such as thinking, reasoning and memory."

　　Shirley Cramer of the Alzheimer's Research UK said: "We do not yet know why obesity and metabolic abnormality are linked to poorer brain performance, but with obesity levels on the rise, it will be important to delve a little deeper into this association.

　　"While the study itself focuses on cognitive decline, previous research suggests that a healthy diet, regular exercise, not smoking and controlling blood pressure and cholesterol in midlife can also help stave off dementia. With dementia figures spiralling towards a million, the findings suggest we should be conscious of our general health throughout life."