好英语网有机食品未必更有营养
Does an organic strawberry contain more vitamin C than a conventional one?
有机草莓的维生素C含量真的比普通草莓高吗？
Maybe — or maybe not.
答案是：未必。
普通草莓农田。研究者表示有机食物比起普通食物，并不会更有营养，受污染的危险性也一点儿都不低。
Stanford University scientists have weighed in on the “maybe not” side of the debate after an extensive examination of four decades of research comparing organic and conventional foods.
过去40多年中，大量针对有机食物与普通食物的比较研究陆续问世。在对这些研究进行全面检验评估后，斯坦福大学(Stanford University)的科学家们站到了宁可信其无的这一阵营。
They concluded that fruits and vegetables labeled organic were, on average, no more nutritious than their conventional counterparts, which tend to be far less expensive. Nor were they any less likely to be contaminated by dangerous bacteria like E. coli.
研究者得出的结论是，带有有机标志的水果和蔬菜总体上并不比普通水果蔬菜更有营养，而后者通常却要便宜得多。此外，有机水果蔬菜被大肠杆菌等致病菌污染的危险性也一点儿都不低。
The researchers also found no obvious health advantages to organic meats.
研究者还发现，有机肉类并不会带来明显的健康收益。
Conventional fruits and vegetables did have more pesticide residue, but the levels were almost always under the allowed safety limits, the scientists said. The Environmental Protection Agency sets the limits at levels that it says do not harm humans.
科学家指出，普通水果蔬菜的确含有更高的农药残留，但大多数情况下并未超过标准允许的安全范围。制定标准的美国国家环境保护局(The Environmental Protection Agency)宣称，该范围内的农药残留不会对人体造成危害。
“When we began this project, we thought that there would likely be some findings that would support the superiority of organics over conventional food,” said Dr. Dena Bravata, a senior affiliate with Stanford’s Center for Health Policy and the senior author of the paper, which appears in Tuesday’s issue of the Annals of Internal Medicine. “I think we were definitely surprised.”
“项目开始时，我们本以为会发现一些支持有机食品优越性的结果，”斯坦福大学卫生政策中心资深研究员德娜·布拉瓦塔(Dena Bravata)博士表示。“可想而知，我们都十分吃惊。”布拉瓦塔是上周二发表于《内科学年鉴》(Annals of Internal Medicine)的该篇论文的资深作者。
The conclusions will almost certainly fuel the debate over whether organic foods are a smart choice for healthier living or a marketing tool that gulls people into overpaying. The production of organic food is governed by a raft of regulations that generally prohibit the use of synthetic pesticides, hormones and additives.
毋庸置疑，这些结论将会点燃一场论战：有机食品到底是为了健康生活的理性选择，还是骗人们花冤枉钱的营销手段？目前，有机食品的生产受到一系列法规监管，通常禁止使用化学农药、激素和添加剂。
The organic produce market in the United States has grown quickly, up 12 percent last year, to $12.4 billion, compared with 2010, according to the Organic Trade Association. Organic meat has a smaller share of the American market, at $538 million last year, the trade group said.
美国的有机产品市场发展迅猛。来自有机贸易协会(Organic Trade Association)的数据显示，与2010年相比，2011年一年的增长幅度高达12%，市场总额约为124亿美元。该协会表示，有机肉类在美国市场上相对份额较小，去年的市场总额为5.38亿美元。
The findings seem unlikely to sway many fans of organic food. Advocates for organic farming said the Stanford researchers failed to appreciate the differences they did find between the two types of food — differences that validated the reasons people usually cite for buying organic. Organic produce, as expected, was much less likely to retain traces of pesticides.
新的发现似乎不会动摇许多有机食品爱好者的立场。倡导有机农业的人指出，斯坦福大学的研究人员没能充分意识到他们发现的两种食物之间差别的重要性——许多人正是出于这一差别才选择购买有机食物。正如所预料的，有机产品含有农药残留的可能更小。
Organic chicken and pork were less likely to be contaminated by antibiotic-resistant bacteria.
有机鸡肉和猪肉也不易被耐药菌污染。
“Those are the big motivators for the organic consumer,” said Christine Bushway, the executive director of the trade association.
“这些才是有机产品消费者的主要动机，”有机贸易协会执行主任克里斯蒂娜·布什韦(Christine Bushway)指出。
The study also found that organic milk contained more omega-3 fatty acids, which are considered beneficial for the heart.
该项研究还发现，有机牛奶的Ω-3脂肪酸含量更高，该种脂肪酸被认为有益于心脏。
“We feel organic food is living up to its promise,” said Sonya Lunder, a senior analyst with the Environmental Working Group, which publishes lists highlighting the fruits and vegetables with the lowest and highest amounts of pesticide residues.
“我们觉得有机食品信守了其承诺，”环境工作组(Environmental Working Group)的资深分析师索尼娅·伦德(Sonya Lunder)表示。该组织发布名单，重点列出农药残留量最低的水果和蔬菜。
The Stanford researchers said that by providing an objective review of the current science of organic foods, their goal was to allow people to make informed choices.
斯坦福大学的研究人员指出，通过对当前关于有机食物的科学研究进行客观回顾，他们希望大众可以在充分知情的基础上做出选择。
In the study — known as a meta-analysis, in which previous findings are aggregated but no new laboratory work is conducted — researchers combined data from 237 studies, examining a wide variety of fruits, vegetables and meats. For four years, they performed statistical analyses looking for signs of health benefits from adding organic foods to the diet.
该项研究采用的是荟萃分析(meta-analysis)方法，即不进行新的实验室工作，仅就此前的研究发现加以统合分析。研究人员合并了237项研究得出的数据，检测范围涵盖了为数众多的水果、蔬菜和肉类。四年来，他们进行各种数据分析，以期看到在食谱中增加了有机食物可能会给健康带来的益处。
The researchers did not use any outside financing for their research. “I really wanted us to have no perception of bias,” Dr. Bravata said.
研究人员并未就此项研究获得任何外部资助。布拉瓦塔博士指出，“我真的不想让我们心存任何偏见。”
One finding of the study was that organic produce, over all, contained higher levels of phosphorus than conventional produce. But because almost everyone gets adequate phosphorus from a wide variety of foods, they said, the higher levels in the organic produce are unlikely to confer any health benefit.
该项研究的一个发现是，有机农产品总体上微量元素磷的含量较高。但鉴于几乎所有人都能从种类繁多的食物中获取足够的磷，研究者不认为有机农产品中较高的磷含量会带来任何健康益处。
The organic produce also contained more compounds known as phenols, believed to help prevent cancer, than conventional produce. While the difference was statistically significant, the size of the difference varied widely from study to study, and the data was based on the testing of small numbers of samples. “I interpret that result with caution,” Dr. Bravata said.
相对于普通农产品，有机农产品中的酚类化合物含量也较高。这种化合物被认为具有防癌功效。然而，尽管有机与非有机产品之间的差异显著，各项研究之间的差值却也变化悬殊，而且数据是基于小样本检测而得出。“对于这一结果的解读，我持谨慎态度，”布拉瓦塔博士表示。
Other variables, like ripeness, had a greater influence on nutrient content. Thus, a lush peach grown with the use of pesticides could easily contain more vitamins than an unripe organic one.
其他变量——如水果和蔬菜的成熟度——对于营养成分的影响更大。因此，一枚使用农药但熟透了的桃子轻而易举便可以在维生素含量上打败青涩的有机桃子。
The study’s conclusions about pesticides did seem likely to please organic food customers. Over all, the Stanford researchers concluded that 38 percent of conventional produce tested in the studies contained detectable residues, compared with 7 percent for the organic produce. (Even produce grown organically can be tainted by pesticides wafting over from a neighboring field or during processing and transport.) They also noted a couple of studies that showed that children who ate organic produce had fewer pesticide traces in their urine.
该项研究关于农药的结论看来倒有可能会讨有机食品消费者们的欢心。斯坦福大学的研究人员指出，总体上，此前系列研究所测试的普通农产品中，38%含有可测出的农药残留，而有机农产品的该项数据为7%。（即便是有机种植的农产品，也有可能被从邻近农田中随空气或水流传来的农药污染。）他们还注意到，一两项研究显示，食用有机农产品的儿童尿液中农药残留含量较低。
Dr. Bravata agreed that people bought organic food for a variety of reasons — concerns about the effects of pesticides on young children, the environmental impact of large-scale conventional farming and the potential public health threat if antibiotic-resistant bacterial genes jumped to human pathogens. “Those are perfectly valid,” she said.
布拉瓦塔博士承认，人们购买有机食物是出于不同原因——担心农药对年幼儿童的影响，担心大规模使用农药和激素的农业种植方式对环境的破坏，担心耐药菌基因与人体内病原体结合后产生的潜在公共卫生威胁。她表示，“这些原因都相当说得通”。
The analysis also did not take factors like taste into account.
该项分析也并未将口味这一要素纳入考虑范围内。
But if the choice were based mainly on the hope that organic foods would provide more nutrients, “I would say there is not robust evidence to choose one or the other,” Dr. Bravata said.
但如果选择有机产品的主要原因是寄希望于它能提供更多营养成分的话，“照我看，目前还没有可靠的证据支持这种选择，”布拉瓦塔博士表示。
The argument that organic produce is more nutritious “has never been major driver” in why people choose to pay more, said Ms. Lunder, the Environmental Working Group analyst.
环境工作组的分析师伦德女士则指出，有机农产品是否更有营养“从来都不曾成为（消费者选择多花点钱的）主要原因。”
Rather, the motivation is to reduce exposure to pesticides, especially for pregnant women and their young children. Organic food advocates point to, for example, three studies published last year, by scientists at Columbia University, the University of California, Berkeley, and Mount Sinai Hospital in Manhattan. The studies identified pregnant women exposed to higher amounts of pesticides known as organophosphates and then followed their children for years. In elementary school, those children had, on average, I.Q.’s several points lower than those of their peers.
相反，减少农药暴露才是真正的驱动力，尤其是对于怀孕女性和婴幼儿。推崇有机食物的人指出，哥伦比亚大学(Columbia University)、加州大学伯克利分校(University of California, Berkeley)和曼哈顿西奈山医院(Mount Sinai Hospital)的科学家去年分别发表的三项研究就是证据。这些研究找到那些怀孕期间接触过较高剂量的有机磷酸酯类农药的女性，并对她们生下的孩子进行了数年的跟踪调查。上小学时，这些孩子的智商要比其他孩子平均低好几分。