2017年职称英语 考试 报名,2017年职称英语综合类B级阅读材料精选(9)

　　节食可能使你健康长寿，但并不好玩——节食可能不是非做不可的事。即使上了年纪再节食，我们仍然有可能在很大程度上保持青春活力。

　　StephenSpindler和他在Riverside的加利福尼亚大学的同事们已经发现，一只高龄老鼠只要连续四周限制它进食，它的某些肝脏基因就会变得和衰老前一样充满活力，老鼠的肝基因恢复活力不会逆转老鼠在其他方面的老化，但却有助于肝脏代谢药物或除去毒素。

　　Spindler的团队正常饲养三只老鼠直到它们死，而另外三只老鼠只喂正常饲料定量的一半。另外三只老鼠在34个月大的时候——相当于人的70岁，从正常饲养转到半量饲养一个月。

　　研究者检查了这些老鼠肝脏的11000个基因的活动，发现正常饲养的老鼠随着年龄的增长有46条肝脏基因发生变化。这种变化与炎症和身体组织无限激增相关——这大概对老鼠的健康来说是个坏消息。在那些终生节食的老鼠中，这46条肝脏基因中的27条继续像年轻的基因一样活动，但最惊人的发现是那些上了年纪才开始节食的老鼠也能从70%的基因变化中受益。

　　华盛顿附近的国家老年协会的HuberWarner说：“这是这些影响迅速起作用的第一个迹象。”

　　还没有知道热量限制是否在人身上和在老鼠身上一样起作用，但是Spindler怀有希望。他说：“有吸引人的证据表明它能起作用。”

　　如果它确实能在人身上起作用，那就有足够的理由使肝脏焕发青春秋战国。当我们变老时，我们的身体对药物的新陈代谢就不那么高效。Spindler说短期的节食足以使药物充分发挥药效。

　　但是Spindler不能肯定节食是否值得。他说：“老鼠们病少了，活的更长，但是它们感到饥饿。即便明白节食的作用，仍旧很难在饭馆里说我只吃一半。”

　　Spindler希望在不久的将来，我们不必节食，他的公司，加利福尼亚寿命遗传学，正在寻找有热量控制作用的药物。

Eat to Live

　　A meager diet may give you health and long life, but it’s not much fun—and it might not even be necessary. We may be able to hang on to most of that youthful vigor even if we don’t start to diet until old age.

　　Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse’s liver genes can be made to behave as they did when the mouse was young simply by limiting its food for four weeks. The genetic rejuvenation won’t reverse other damage caused by time for the mouse, but could help its liver metabolize drugs or get rid of toxins.

　　Spindler’s team fed three mice a normal diet for their whole lives, and fed another three on half-rations. Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old—equivalent to about 70 human years.

　　The researchers checked the activity of 11,000 genes from the mouse livers, and found that 46 changed with age in the normally fed mice. The changes were associated with things like inflammation and free radical production—probably bad news for mouse health. In the mice that had dieted all their lives, 27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 per cent of these gene changes.

　　“This is the first indication that thee effects kick in pretty quickly,” says Huber Warner from the National Institute on Aging near Washington, D. C.

　　No one yet knows if calorie works in people as it does in mice, bus Spindler is hopeful. “There’s attracting and tempting evidence out there that it will work,” he says.

　　If it does work in people, there might be good reasons for rejuvenating the liver. As we get older, out bodies are les efficient at metabolizing drugs, for example. A brief period of time of dieting, says Spindler, could be enough to make sure a drug is effective.

　　But Spindler isn’t sure the trade-off is worth it. “The mice get less disease, they live longer but they’re hungry,” he says. “Even seeing what a diet does, it’s still hard to go to a restaurant and say: ‘I can only eat half of that’.”

　　Spindler hopes we soon won’t need to diet at all. His company, Life Span Genetics in California, is looking for drugs that have the effects of calorie restriction.

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