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  3. For years the media, food labels, dietitians, and even scientists who should

For years the media, food labels, dietitians, and even scientists who should

游客2023-09-06  21
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. [br] What does the passage suggest people do?
选项 A、Supply antioxidants regularly.
B、Don’t take extra antioxidants.
C、Take enough vitamins.
D、Take more fruits and vegetables.
答案 B
解析 本文首段指出人们常被建议补充尽量多的抗氧化剂，因为他们可以破坏导致各种疾病的自由基。第二段直接用“不要这么快下结论”表示对以上观点的不认同，接着论述了抗氧化剂对人体健康的危害，并分析了其中的原因。因此本文是在告诫人们不要服用额外的抗氧化剂，故答案为[B]，同时排除[A]“有规律的使用抗氧化剂”。维生素也是抗氧化剂的一种，故可以排除[C]。[D]“吃更多的水果和蔬菜”未在文中提到，故排除。
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