有机牛奶中有益脂肪酸含量更高

More Helpful Fatty Acids Found in Organic Milk
By KENNETH CHANGDecember 23, 2013
有机牛奶中有益脂肪酸含量更高
个人健康KENNETH CHANG2013年12月23日

Whole milk from organic dairies contains far more of some of the fatty acids that contribute to a healthy heart than conventional milk, scientists are reporting.
科学家们报告，在使用有机乳制品加工而成的全脂牛奶中，有利于心脏健康的某些脂肪酸的含量高于普通牛奶。
The finding, [要查看本链接请先注册并登录] in the journal PLOS One, is the most clear-cut instance of an organic food’s offering a nutritional advantage over its conventional counterpart. [要查看本链接请先注册并登录]have been less conclusive.
该研究周一发表在[要查看本链接请先注册并登录](PLOS One)杂志上，它为有机食品的营养优于普通食品提供了迄今为止最明确的例证。相比之下，[要查看本链接请先注册并登录]则一直没有获得定论。
Drinking whole organic milk “will certainly lessen the risk factor for cardiovascular disease,” said the study’s lead author, Charles M. Benbrook, a research professor at Washington State University’s Center for Sustaining Agriculture and Natural Resources.
饮用全脂有机牛奶“毫无疑问可以减少心血管疾病的风险因素，”该研究的主要作者、华盛顿州立大学(Washington State University)可持续农业与自然资源中心(Center for Sustaining Agriculture and Natural Resources)的研究教授查尔斯·M·本布鲁克(Charles M. Benbrook)表示。
“All milk is healthy and good for people,” he continued, “but organic milk is better, because it has a more favorable balance of these fatty acids” — omega-3, typically found in fish and flaxseed, versus omega-6, which is abundant in many fried foods like potato chips.
“所有的牛奶都有益于人体健康，”他继续解释道，“但有机牛奶相对更好，因为有机牛奶之中脂肪酸的配比更加均衡”——这些脂肪酸包括了omega-3（通常存在于鱼类和亚麻籽中）与omega-6（在薯片等油炸食品中含量丰富）。
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一项研究显示，饮用有机牛奶相比普通牛奶，更有可能减少患心血管病的风险。
Evan Sung for The New York Times
Under government requirements for organic labeling, dairy cows must spend a certain amount of the time in the pasture, eating grassy plants high in omega-3s; conventional milk comes from cows that are mostly fed corn, which is high in omega-6s. Nonorganic cows that graze in pastures also produce milk with greater amounts of omega-3s.
美国政府对使用“有机”标签要求甚高：这些奶牛必须在牧场上养殖达到一定时间，并食用富含omega-3脂肪酸的牧草；而产普通牛奶的奶牛大多以富含omega-6脂肪酸的玉米来饲喂。在牧场上养殖的非有机奶牛所生产的牛奶也含有较多的omega-3脂肪酸。
The research was largely funded by Organic Valley, a farm cooperative that sells organic dairy products. But experts not connected with the study said the findings were credible — though they noted that the role of milk in a healthy diet and the influence of fatty acids in preventing or causing cardiovascular disease are far from settled.
该研究主要由有机谷（Organic Valley，一家销售有机乳制品的农场合作社）资助。但与该研究无关的专家认为这一研究结果具有可信性——不过他们同时也指出，牛奶在健康饮食中的作用以及脂肪酸对心血管疾病致病或预防的影响还远远没有得到确定。
“I think this is a very good piece of work,” said Dr. Joseph Hibbeln, a nutritional neuroscientist at the National Institutes of Health.
“我认为这项工作非常出色，”美国国立卫生研究院(National Institutes of Health，N.I.H)的营养神经科学家约瑟夫·希波尔恩(Joseph Hibbeln)博士评论称。
The researchers looked at 384 samples of organic and conventional whole milk taken over 18 months around the country. Although the total amount of fat was almost the same, the organic milk contained 62 percent more omega-3 fatty acids and 25 percent fewer omega-6s.
在18个月期间，研究人员检查了来自全美国的384份有机和普通全脂牛奶的样本。虽然其脂肪总量几乎完全相同，但有机牛奶中的omega-3脂肪酸含量要高出62%，omega-6脂肪酸含量则低了25%。
The ratio of omega-6 to omega-3 in the organic milk was 2.28, much lower than the 5.77 ratio in conventional milk. (The figures do not apply to nonfat milk, which strips away the fatty acids.)
有机牛奶中omega-6脂肪酸与omega-3脂肪酸的比例为2.28，大大低于普通牛奶中的5.77。（这些数字不适用于脱脂牛奶，因为脱脂牛奶中去除了所有脂肪酸。）
Nutrition experts broadly agree that omega-3 acids offer numerous health benefits. That was the impetus for the United States Department of Agriculture to urge people to eat more seafood when it revised its dietary guidelines in 2010.
营养专家们广泛认同omega-3脂肪酸可提供众多健康效益。因此美国农业部(United States Department of Agriculture)在2010年修订其膳食指南时，呼吁人们多吃海产品。
But experts disagree sharply whether omega-6 consumption should be reduced.
但专家们尚未就是否应减少omega-6脂肪酸的摄入量达成一致意见。
In ancient times, people ate roughly equal amounts of the two fatty acids. Today most Americans now eat more than 10 times as much omega-6, which is prevalent in certain vegetable oils and thus also fried foods, as omega-3.
在古代，人们对这两种脂肪酸的摄取量大致相等。而今，由于某些植物油和油炸食品中含有大量的omega-6脂肪酸，大多数美国人的omega-6脂肪酸摄取量可达omega-3脂肪酸的10倍以上。
While omega-6 is essential, some health studies suggest that such a wide disparity is associated with many ills, Dr. Benbrook said. A shift to drinking organic whole milk — and raising consumption from the currently recommended three servings a day to 4.5 — would take a big step to lowering the ratio, he said, although adjustments would have to be made elsewhere in the diet to offset the added calories of the milk fat.
尽管omega-6脂肪酸必不可少，但本布鲁克博士说，一些健康研究表明，两种脂肪酸的摄取量存在如此巨大的差距与许多疾病都具有相关性。他认为，从饮用普通全脂牛奶改为饮用有机全脂牛奶，并将摄入量从当前建议的每天3份提高至4.5份，将大幅缩小上述比例。不过，他补充道，这就需要对膳食的其他方面进行调整，以抵消牛奶脂肪中额外的那部分热量。
Donald R. Davis, another of the study’s authors, said the longstanding assumption that the saturated fats in whole milk raise the risk of cardiovascular disease has been questioned in recent years.
该研究的另一名作者唐纳德·R·戴维斯(Donald R. Davis)表示，长期以来，人们一直猜测全脂牛奶中的饱和脂肪会提高心血管疾病的风险，但近年来这种假设受到了质疑。
Dr. Walter Willett, chairman of the nutrition department at the Harvard School of Public Health, did not question the underlying data in the study. But he said the conclusions and recommendations were based on the “false assumption” that omega-6 fatty acids are harmful.
哈佛大学公共卫生学院(Harvard School of Public Health)的营养系主任沃尔特·威利特(Walter Willett)博士并没有对该研究的基础数据表示疑议。但他指出，该研究将结论和建议建立在了omega-6脂肪酸有害健康这一“错误假设”之上。
Dr. Willett said omega-6s were actually associated with a lower risk of heart disease, and he called the ratio of omega-6s to omega-3s “irrelevant.” People should try to eat more of both, he said.
威利特博士认为，omega-6脂肪酸其实与较低的心脏病风险相关，并称omega-6与omega-3脂肪酸间的比例“无关紧要”。他说，这两类脂肪酸人们都应该多吃。
And he noted that milk was not essential to a healthy diet; adults in many countries drink little or none. “We don’t know all the long-term consequences, so I think the best strategy given current knowledge is to keep intake low to moderate (as in the Mediterranean diet) if it is consumed at all,” Dr. Willet wrote in an email.
此外他还指出，牛奶并非健康饮食的必要组成部分；在许多国家中，成年人很少甚至完全不饮用牛奶。“我们还没有尽知所有的长期后果，因此我认为，鉴于现有的知识，最佳策略是：如果食用牛奶，保持低到中度的摄入量（与地中海饮食中的摄入量一致）比较合适，”威利特博士在一封电子邮件中写道。
But Dr. Hibbeln of the National Institutes of Health, who has conducted research on the effects of fatty acids on heart disease, said animal studies showed that high levels of omega-6s interfered with omega-3s.
但一直就脂肪酸对心脏病的影响开展研究的美国国立卫生研究院的希波尔恩博士提出，动物实验表明，高水平的omega-6脂肪酸与omega-3脂肪酸会出现相互干扰。
At the same time, though, he cautioned that the mix of omega-3s in milk is different from that in fatty fish. The simple ratio, he said, “is not as meaningful as we would like it to be.”
他也提醒说，另一方面，牛奶中各种omega-3脂肪酸的组合与多脂鱼中的有所不同。单纯的比例数字“并不像我们期望的那样有意义”。
Still, he endorsed the organic milk recommendation. “You’re heading in the right direction,” he said.
不过，他仍然赞同建议食用有机牛奶。“这是正确的前进方向，”他说。
Organic Valley uses independent milk-processing companies around the country, allowing the researchers to compare samples of organic milk with conventional milk from the same region.
有机谷在美国各地均采用了独立的牛奶加工企业，这确保了研究人员可以对来自同一地区的有机牛奶与普通牛奶样品进行比较。
The company provided $45,000 for an independent laboratory to measure the fatty acids, and it is a corporate sponsor of Dr. Benbrook’s program at Washington State. The university spent $90,000 to analyze the data and prepare the paper for publication.
该公司出资4.5万美元请独立的实验室完成了脂肪酸测定。同时，它也是华盛顿州立大学本布鲁克博士研究计划的企业赞助商。该大学在数据分析和准备论文投稿方面约耗资9万美元。
George Siemon, chief executive of Organic Valley, said he was hoping to gain a better idea of how organic foods differ from conventionally produced ones.
有机谷的首席执行官乔治·西蒙(George Siemon)表示，关于有机食品与常规生产的食品有何不同，他很希望能获得更好的认识。
“Organics have lacked a science base,” Mr. Siemon said. “I just wanted to know.”
“有机食品一直缺乏科学的基础，”西蒙说，“而我只是想知道更多。”