2. 外语
  3. For years the media, food labels, dietitians, and even scientists who should know better have bombarded (轰炸) us with advice to l

For years the media, food labels, dietitians, and even scientists who should know better have bombarded (轰炸) us with advice to l

admin2013-05-04  28
问题     For years the media, food labels, dietitians, and even scientists who should know better have bombarded (轰炸) us with advice to load up on antioxidants: compounds found mostly in fruits and vegetables that mop up free radicals, which are highly reactive clusters of atoms that have been fingered as the evil-doers responsible for aging and for illnesses from cancer to heart disease.
    Not so fast. First, studies piled up showing that taking antioxidants—even such common and seemingly harmless ones as vitamins C and E—as supplements was not beneficial to health and might even be dangerous. Many of the free radicals that are neutralized by antioxidants perform valuable functions in the body. The most important:fighting toxins (毒素) and fighting cancer. Maybe it’s not such an excellent idea to flood the body with something that neutralizes these warriors of the immune system. Or as British chemist and science writer David Bradley noted in his blog,Reactive Reports,"It’s always struck: me as odd that you would want to absorb extra antioxidants anyway, given that oxidizing agents are at the front-line of immune defense against pathogens (病原体) and cancer cells...Suffice to say that taking antioxidant supplements... may not necessarily be good for your health if you already have health problems, especially cancer or an infection. "
    The first hints that the trend was crashing came from the hundreds of studies that have tried to assess the health effects of antioxidant supplements. The results have not been pretty. In 2008 the Cochrane Collaboration, an international organization of scientists who assess medical research, carefully checked 67 studies with nearly 400,000 participants. The goal;to determine whether antioxidant supplements reduce mortality in either healthy people or in people with diseases. Conclusion:" We found no evidence to support antioxidant supplements for primary or secondary prevention, and Vitamin A and E may increase mortality. " In analyses of antioxidant supplements and Lou Gehrig’s disease, Alzheimer’s or mild cognitive impairment, and lung cancer, the Cochrane scientists’ verdict was the same: no. And each analysis had an alarming refrain about increasing overall mortality.
    It’s not clear why antioxidants in supplement form might be so dangerous. One idea holds that at high doses they become pro-oxidants,stimulating the harmful DNA- and cell-damaging reactions they’re supposed to prevent. But a more likely explanation is that we are seeing the human version of what scientists are finding in studies of lab animals: antioxidants interfere with immune-system cells that fight infection and cancer.
The Cochrane Collaboration have found antioxidant supplements could______.
选项 A、reduce the mortality of unhealthy people
B、increase the overall mortality of people
C、reduce the overall mortality of people
D、reduce the mortality of healthy people
答案B
解析 事实细节题。定位句指出在2008年，协作网仔细审查了包括将近400，000名参与者在内的67项研究，没有发现任何证据表明抗氧化物补充剂有主要或次要的预防作用，维他命A和E极有可能使死亡率更高。因此，B)“增加人们的死亡率”，符合题意，故为本题答案。A)“减少不健康人群的死亡率”与原文意思相反，故排除；C)“减少人们的死亡率”与原文中的Vitamin A and E may increase mortality意思相反，故排除；D)“减少健康人群的死亡率”，协作网的研究是针对健康人群和非健康人群两大群体的，得出的结果也是关于这两大群体的，该选项与原文increase mortality相反，故排除。
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