精选优质文档-----倾情为你奉上 [2010.04.08] Protection racket 保护的喧闹Eating lots of fruit and vegetables may not help stave off cancer, after all终究， 吃大量的水果和蔬菜并不能避免癌症Apr 8th 2010 | From The Economist print edition FOR snivelling children and recalcitrant carnivores, requests that they should eat five portions of fruit and vegetables every day have mostly fallen on deaf ears. But those who did comply with official advice from charities, governments and even the mighty World Health Organisation (WHO), could remind themselves, rather smugly, that the extra greens they forced down at lunchtime would greatly reduce their chances of getting cancer. Until now, that is. Because a group of researchers led by Paolo Boffetta, of the Mount Sinai School of Medicine in New York, have conducted a new study into the link between cancer and the consumption of fruit and vegetables, and found it to be far weaker than anyone had thought.对于哭哭啼啼的小孩和顽固的肉食主义者，每天吃五种不同的蔬菜和水果的要求他们基本上会当做耳旁风。
但是那些遵循慈善团体、 政府、 甚至是权威的WHO的官方建议的人会沾沾自喜的提醒自己午饭时候硬塞进去的绿色食品会极大的减少患癌症的几率 到现在为止， 确实如此 因为由纽约西奈山医学院的Paolo Boffetta带领的一组研究人员进行了一个癌症与蔬菜和水果的消费之间关系的研究， 并且发现这个关系要比想象得弱得多In the past, veggie-associated reductions of cancer-risk rates as high as 50% had been reported. But it appears that some of these early investigations may have been biased by the use of “case-control” studies. Such studies try to identify the factors contributing to cancer by comparing people who have the disease with those who do not, but are otherwise similar. The problem is that they can easily be biased if researchers do not adequately establish that the two groups being compared are, indeed, otherwise similar. Walter Willet, at the Harvard School of Public Health, says it appears that earlier investigations were more likely to use health-conscious people as their controls. These types of people are, unsurprisingly, more likely to agree to be interviewed about their health than slobby couch potatoes.过去曾有过蔬菜能够减少高达50%的癌症发病率的报道。
但是现在看来先前许多的研究都用了“病例对照”而产生了偏见 这一类研究通过对比其它条件相似的癌症患者和健康人试图明确是什么因素导致了癌症 问题是如果研究人员没有适当地建立两个组， 也就是其它因素都相似， 研究很容易产生偏见 哈佛公共卫生学院的Walter Willet说， 以前的研究似乎都喜欢用有健康意识的人来作为对照组 毫不意外， 这类人比那些懒在沙发里面吃薯片的人更喜欢坐健康的研究 Dr Boffetta and his colleagues have therefore carried out a different kind of study, known as prospective cohort study, which they report in theJournal of the National Cancer Institute. Their work follows a group of individuals over time and looks at how different factors contribute to different outcomes—in this case, the development of cancer. Analysis of dietary data from almost 500,000 people in Europe found only a weak association between high fruit and vegetable intake and reduced overall cancer risk.因此Boffetta博士和同事进行了另一种类型的研究， 被称作是前瞻性群体研究， 发表在《美国癌症学会杂志》上面。
他们在一段时间内跟踪一组个体并观察不同的因素导致了什么样的不同结果——在这个研究中， 就是癌症的发生 欧洲将近500,000人中的饮食数据分析发现大量的蔬菜和水果的摄入与所有的癌症患病率之间的关系非常小 Green with envy充满嫉妒According to Susan Jebb, of the British Medical Research Council’s Collaborative Centre for Human Nutrition Research in Cambridge, the new study suggests that if Europeans increased their consumption of fruit and vegetables by 150g a day (about two servings, or 40% of the WHO’s recommended daily allowance), it would result in a decrease of just 2.6% in the rate of cancers in men and 2.3% in women. Even those who eat virtually no fruit and vegetables, the paper suggests, are only 9% more likely to develop cancer than those who stick to the WHO recommendations.来自英国医学研究会的剑桥人类营养研究合作中心的Susan Jebb说， 新的研究表明如果欧洲人每天增加150g的蔬菜和水果的摄入量（大约每日两次， 或者是WHO推荐摄入量的40%）, 这将只会降低男性2.6%、 女性2.3%的肿瘤发生率。
研究显示即使是那些几乎没有蔬菜和水果摄入的人， 他们的癌症发生率比坚持按照WHO推荐摄入量的人仅仅高出9%On the face of it, that is quite a blow to the smug salad eaters, and the health lobby’s spin-doctors were out in force in the wake of the paper’s publication, to play down its conclusions. Before racing to the food-recycling bin with the contents of an ageing fruit bowl, they pointed out, there are a number of other factors that nutritionists would urge that you consider.从表面看来， 这无疑是对沾沾自喜的沙拉坚守者的巨大打击， 而且这篇文章发表以后倡导健康生活的医生们失去了自己以前说服病人的有力证据， 他们闭口不谈这篇文章的重要性。
营养专家指出， 别急着把你一直伴随你的水果盘里面的水果扔到垃圾桶里， 还有很多其它的因素需要你考虑 One is that this kind of study has attempted to adjust for every possible factor that might contribute to the relationship, and isolate only the contribution that fruit and vegetables make. This means that if people who turn away from fruit and vegetables end up eating more processed meats or foods high in fat instead, they probably will increase their cancer risk, even though the direct cause is not the consumption of less fruit and veg.其中一个因素是这一类型的研究试图调节好在这个关系中的每一个因子， 于是孤立了蔬菜和水果在其中所起到的作用。
这意味着如果把吃蔬菜和水果转而变成吃更多的精细肉类和其他高脂食物， 会增加癌症的发病率， 即便直接的原因并不是蔬菜和水果的摄入过少 More importantly, there is still good evidence that fruit 。