吃有機肉 喝有機奶的人也許真的更健康
Organic meat and milk differ markedly from their conventionally produced counterparts in measures of certain nutrients, a review of scientific studies reported on Tuesday.
週二（2月9日），一項科學研究綜述報告，有機肉類和牛奶在某些營養成分上與通過常規方式生產的同類產品間存在明顯差異。
In particular, levels of omega-3 fatty acids, beneficial for lowering the risk of heart disease, were 50 percent higher in the organic versions.
尤其是，有機產品中有益於降低心臟病風險的ω-3脂肪酸的水平比普通產品高出50%。
“The fatty acid composition is definitely better,” said Carlo Leifert, a professor of ecological agriculture at Newcastle University in England and the leader of an international team of scientists who performed the review.
該綜述由一國際科學家小組完成，其負責人，英格蘭紐卡斯爾大學(Newcastle University)的生態農業教授卡洛·萊費特(Carlo Leifert)說：“（有機產品的）脂肪酸組成絕對更佳。”
The European Commission, the executive body of the European Union, and the Sheepdrove Trust, a British charity that supports organic farming research, paid for the analysis, which cost about $600,000.
該項分析耗資約60萬美元，這些費用由歐盟(European Union)的執行機構歐盟委員會(European Commission)和支持有機農業研究的英國慈善機構Sheepdrove Trust承擔。
However, the question of whether these differences are likely to translate to better health in people who eat organic meat and drink organic milk is sharply disputed.
然而，上述差異是否代表着吃有機肉類、喝有機牛奶的人更爲健康呢？人們對此仍有尖銳的爭議。
“We don’t have that answer right now,” said Richard P. Bazinet, a professor of nutritional sciences at the University of Toronto who was not involved with the research. “Based on the composition, it looks like they should be better for us.”
“這個問題的答案我們現在還不得而知，”多倫多大學(University of Toronto)的營養科學教授理查德·P·巴齊內(Richard P. Bazinet)說，他沒有參與上述研究。“但就營養組成而言，它們（有機產品）似乎更爲有益。”
The two new scientific papers, published in The British Journal of Nutrition, are not the result of any new experiments, but instead employ a statistical technique called meta-analysis that attempts to pull robust conclusions out of many disparate studies.
這兩篇新的科學論文發表在《英國營養學雜誌》(The British Journal of Nutrition)上，它們並沒有介紹什麼新的實驗結果，而是採用了一種名爲薈萃分析的統計技術，試圖從衆多不同的研究中得出強有力的結論。
They are certain to further stir a combative debate over whether organic foods are healthier. Some scientists assert that organic and conventional foods are nutritionally indistinguishable, and others find significant benefits to organic. Many people who buy organic food say they do so not for a nutritional advantage, but because of environmental concerns and to avoid pesticides.
它們勢必會進一步激起人們就有機食品是否更爲健康展開激烈的辯論。一些科學家宣稱，有機食品和常規食品的營養價值並無區別，而其他人則發現有機產品顯著較好。許多人稱自己購買有機食品並非是爲了更高的營養價值，而是出於對環境的憂慮，以及希望能避免農藥問題。
The higher levels of omega-3, a type of polyunsaturated fat, arise not from the attributes usually associated with organic food — that the animals are not given antibiotics, hormones or genetically modified feed — but rather from a requirement that animals raised organically spend time outside. Organic milk and beef come from cattle that graze on grass, while most conventional milk and beef come from cows subsisting on grain.
ω-3脂肪酸是一種多不飽和脂肪。有機食品中ω-3脂肪酸水平較高，並不是有機食品本身的特點（即不給予動物抗生素、激素或轉基因飼料）造成的，而是因爲有機養殖的動物在室外活動的時間較長。有機牛奶和牛肉產自在草地上放牧的牛，而大多數普通牛奶和牛肉則產自吃穀物的牛。
“It’s not something magical about organic,” said Charles M. Benbrook, an organic industry consultant who is an author of the studies. “It’s about what the animals are being fed.”
“有機食品本身並沒有什麼神奇之處，”研究的作者之一，有機產業顧問查爾斯·M·本布魯克(Charles M. Benbrook)說。“關鍵在於動物是用什麼東西飼餵的。”
Most of the same changes would be observed in conventionally raised animals that also grazed for the majority of their diet, the scientists said.“For once, this is a pretty simple story,” Dr. Benbrook said.
科學家們表示，如果常規飼養的動物也以吃草爲主，那麼在它們身上也能發現很多相同的改變。“這樣一來，問題就變得簡單了，“本布魯克博士說。
The review of comparisons of organic and conventional milk analyzed all 196 papers the scientists found. Because studies of meat are sparser, they could not look at just one type of meat like beef or pork. Instead, they did one analysis of the 67 papers they found for all types of meat. “Only if you throw them all in one pot can you do a meta-analysis,” Dr. Leifert said.
科學家們在比較有機和常規牛奶的綜述中分析了他們所能找到的所有196篇論文。由於對肉類的研究較少，他們發現只審查關於某一種肉，如牛肉或豬肉的研究不現實。反之，他們對關於各種肉的67篇論文統一進行了分析。“只有把它們放在一起才能進行薈萃分析，”萊費特博士解釋道。
Two years ago, Dr. Leifert led a similar review for fruits and vegetables that found organic produce had higher levels of some antioxidants and less pesticide residue than conventionally grown crops.
兩年前，萊費特博士領導了一項關於水果和蔬菜的類似綜述，發現與用常規方法種植的作物相比，有機農產品中某些抗氧化劑的水平較高，農藥殘留較少。
Nutrition experts broadly agree that omega-3 fatty acids in food offer numerous health benefits. When the United States Department of Agriculture revised its dietary guidelines in 2010, it urged people to eat more seafood, which is rich in omega-3.
營養專家普遍認同，食物中的ω-3脂肪酸具有多種健康效益。美國農業部(United States Department of Agriculture)在2010年修訂其膳食指南時，呼籲人們多多食用富含ω-3脂肪酸的海產品。
Omega-3 is much more prevalent in grass than in grain, which is why organic livestock and milk also contain higher levels. “Lo and behold, we altered in some fundamental ways the nutrient intake of these animals and hence the nutrient composition of the products that we derive from those animals,” Dr. Benbrook said.
草料中的ω-3脂肪酸含量比穀物中高，因此有機家畜及其乳製品中也含有較高水平的ω-3脂肪酸。“你瞧，我們改變了這些動物攝入營養的基本方式，這才影響了其衍生產品的營養成分，”本布魯克博士說。
The new analysis found that levels of another polyunsaturated fat, omega-6, were slightly lower in organic meat and dairy. Omega-3 and omega-6 are essential for the functioning of the human body, which can make neither. But some have argued that a skewing toward omega-6 has become unhealthy.
新的分析還發現，在有機肉類和乳製品中，另一種多不飽和脂肪酸：ω-6脂肪酸的水平略低。ω-3和ω-6脂肪酸對於人體的正常功能來說都必不可少，而且人體無法自己合成它們。但也有人認爲，過多攝入ω-6脂肪酸並不利於健康。
Centuries ago, people ate roughly equal amounts of the two fatty acids. Today, most Americans eat more than 10 times as much omega-6, which is prevalent in certain vegetable oils and thus also fried foods, as omega-3.
幾個世紀以前，人們攝入的這兩種脂肪酸大致等量。今天，由於某些植物油中普遍含有ω-6脂肪酸（因此油炸食品也一樣），大多數美國人攝入的ω-6脂肪酸約爲ω-3的10倍以上。
In an email, Dr. Walter C. Willett, the chairman of the nutrition department at the Harvard T.H. Chan School of Public Health, said the differences between organic and conventional beef were trivial, and the amount of saturated fat in both were high.
哈佛大學公共衛生學院(Harvard School of Public Health)的營養系主任沃爾特·C·威利特(Walter C. Willett)博士在一封電子郵件中寫道，有機和常規牛肉之間的差異微不足道，而且兩者中的飽和脂肪含量均很高。
“Far greater, and beneficial, differences in fatty acids are seen if poultry and fish replace red meat,” Dr. Willett said.
“如果用禽肉和魚肉來代替紅肉，你會發現更大、更有益於健康的脂肪酸差異，”威利特博士如是說。
A shortcoming of the recommendation to eat more fish is that if everyone followed it, the rivers, oceans and lakes would be emptied of fish. Dr. Bazinet of the University of Toronto said perhaps encouraging people to switch to organic meats and milk would be “a way to kind of get at them with the foods they’re already eating.”
不過，多吃魚這個建議本身也有其缺點：如果每個人都遵循這個建議，那麼河流、海洋和湖泊中的魚就要被吃光了。多倫多大學的巴齊內博士表示，鼓勵人們改吃有機肉類和牛奶或許“只是在教人攝入本來就在吃的食物”。
Dr. Bazinet said observational studies suggested that adding 200 milligrams a day of omega-3s to an average diet should yield health benefits. Switching to organic beef would add about 50 milligrams. “Eating one grass-fed beef serving per day is not going to do it,” he said.
巴齊內博士說，觀察研究表明，在普通膳食的基礎上，每天增加攝入200毫克ω-3脂肪酸可帶來健康效益。而改吃有機牛肉只能多攝取到約50毫克的ω-3脂肪酸。於是他總結道：“每天吃一份草飼牛肉達不到你（補充ω-3脂肪酸）的目的。”
But if combined with a couple of glasses of organic milk, “it should make a difference,” Dr. Bazinet said. “That would be the hypothesis.”
但是，如果再喝上一兩杯有機牛奶的話，“應該就有用了，”巴齊內博士說。“假設上是如此。”
Scientists are now trying to examine the health question more directly.
現在科學家們正試圖以更直接的方式來探討這些健康問題。
Dr. Leifert cited several studies that indicated that infants of mothers who ate organic fruits and vegetables were less likely to contract some diseases. He is also conducting experiments to see if rats fed organic foods are healthier. So far, he said, it appears that crop pesticide residue does have measurable effects on the rats’ hormones.
萊費特博士列舉了數項研究，它們都表明，食用有機水果和蔬菜的母親所誕下的嬰兒較不容易患某些疾病。他還在進行實驗，以研究飼餵有機食品的大鼠是否更健康。他說，從迄今爲止的結果來看，農作物上的農藥殘留確實對大鼠的激素水平造成了明顯的影響。
“We still don’t know whether it kills you, but we do know it has an effect on hormonal balances,” he said. “It’s something that makes you think a little bit.”
“雖然尚不清楚它是否會致死，但我們的確發現，它會影響激素的平衡。”他說，“這一點頗值得深思。”
