The Search for the Anti·aging Pill单词分析.docVIP

READING PASSAGE 3 You should spend about 20 minutes on Questions 28—40, which are based on Reading Passage 3 The Search for the Anti-·aging Pill In government laboratories and elsewhere, scientists are seeking a drug able to prolong life and youthful vigor．Studies of caloric restriction are showing the way As researchers on aging noted recently, no treatment on the market today has been proved to slow human aging—the build-up of molecular1 and cellular2 damage that increases vulnerability3 to infirmity as we grow older．But one intervention，consumption of a low-calorie*yet nutritionally 6balanced diet．works incredibly well in a broad range of animals，increasing longevity and prolonging good health．Those findings suggest that caloric restriction could delay aging and increase longevity in humans, too． Unfortunately, for maximum benefit，people would probably have to reduce their caloric intake by roughly thirty per cent，equivalent to dropping from 2,500 calories a day to l,750．Few mortals could stick to that harsh a regimen11，especially for years on end．But what if someone could create a pill that mimicked the physiological effects of eating less without actually forcing people to eat less? Could such a‘ caloric-restriction mimetic13’，as we call it，enable people to stay healthy longer, postponing age-related disorders(such as diabetes15，arteriosclerosis，heart disease and cancer)until very late in ife? Scientists first posed this question in the mid-1 990s．after researchers came upon a chemical agent that in rodentsseemed to reproduce many of caloric restrictions benefits．No compound that would safely achieve the same feat in people has been found yet，but the search has been informative and has fanned hope that caloric-restriction (CR) mimetics can indeed be developed eventually． The benefits of caloric restriction The hunt for CR mimetics grew out of a desire to better understand caloric restrictions many effects on the body．Scientists first recognized the value of th