Salmon is good for you — that part we know.
三文鱼有益健康，这一点人所共知。

“Fish is one of the few animal foods consistently linked to health benefits, and salmon is at the top of my list when I recommend fish to people,” said Dr. Dariush Mozaffarian, a distinguished professor and the director of the Food is Medicine Institute at Tufts University.
“鱼类是少数几种能始终与保健联系在一起的动物性食品之一，而当我向人们推荐鱼类的时候，三文鱼就是首选，”塔夫茨大学杰出教授兼食品即良药研究所所长达里乌什·莫扎法里安说道。

But choosing which type to eat for your health — sockeye or coho, wild or farmed — isn’t so obvious. Researchers have found that the nutritional value of salmon can vary depending on the species. And there is a consumer perception that farmed and wild-caught salmon differ in terms of their nutrients and levels of contaminants — beliefs that research partly supports.
但为了健康选择哪种三文鱼——红鲑还是银鲑、野生还是养殖——就没有那么显而易见的答案了。研究人员发现，不同品种的三文鱼营养价值也存在差异。有些消费者认为，养殖三文鱼和野生三文鱼的营养成分和污染水平是不一样的，这一观点得到了一定的研究支持。

From healthy fats to heavy metals, here are answers to all your salmon-related questions.
从健康脂肪到重金属污染，以下是对所有三文鱼相关问题的解答。

What’s so great about salmon?
三文鱼到底好在哪儿？

Dr. Mozaffarian highlighted omega-3 fatty acids — specifically DHA and EPA — as one of salmon’s distinctive nutritional attributes. Salmon packs more DHA and EPA omega-3s than almost any other food, apart from other fatty fish such as herring and sardines.
莫扎法里安强调了Omega-3脂肪酸（特别是EPA和DHA）这种属于三文鱼特色的营养成分。除了鲱鱼和沙丁鱼等富含脂肪的鱼类，三文鱼所含的DHA和EPA类Omega-3脂肪酸几乎比其他任何食物都多。

Studies have consistently linked the consumption of omega-3 fatty acids from seafood to lower rates of stroke and heart disease. Research suggests these fatty acids reduce arterial stiffness, which is associated with high blood pressure, and they may also have anti-inflammatory effects that could be protective against obesity and Type-2 diabetes.
研究一致认为，食用海鲜中的Omega-3脂肪酸可以降低中风和心脏病的发病率。有研究表明，这些脂肪酸能够降低与高血压相关的动脉硬化水平，还可能具有抗炎作用，可以预防肥胖和第二型糖尿病。

Dr. Mozaffarian also said that omega-3s are essential to early life brain development, and emerging evidence suggests that consuming them regularly may guard against age-related cognitive decline and neurodegenerative diseases, such as Alzheimer’s.
莫扎法里安也表示，Omega-3脂肪酸对早期大脑发育至关重要，新证据表明，经常性摄入Omega-3脂肪酸可以预防与年龄相关的认知能力下降和阿尔茨海默氏症等神经退行性疾病。

While the human body is able to make some DHA and EPA on its own, eating foods high in these omega-3s can help ensure the body and brain get what they need, he said. The American Heart Association recommends eating a 3-ounce serving of fish (particularly fatty fish, like salmon) at least twice a week.
他说，虽然人体能自行产生一定的DHA和EPA，但富含Omega-3脂肪酸的食物可以帮助确保身体和大脑获得所需的营养。美国心脏协会建议每周应至少摄入85克鱼类（特别是三文鱼这种脂肪含量高的鱼）两次。

While many supplements contain omega-3s, there’s evidence that getting these fats from seafood may be superior, perhaps because there are compounds in fish meat that help prevent omega-3s from breaking down during digestion.
虽然许多补剂也含有Omega-3脂肪酸，但有证据表明，从海鲜中摄入这些脂肪可能更好，或许是因为鱼肉中的化合物有助于防止Omega-3脂肪酸被消化分解。

In addition, experts say that salmon contains other nutrients, such as protein, selenium and iodide, that may support or augment the healthy effects of these fats. “The focus is usually on omega-3s, but it’s the whole package that makes salmon so healthy,” said Matthew Sprague, a lecturer in nutrition at the University of Stirling Institute of Aquaculture in the United Kingdom.
此外，专家称三文鱼还含有其他营养物质，如蛋白质、硒和碘化物，可能支持或增强这些脂肪的保健作用。“人们通常强调的是Omega-3脂肪酸，但三文鱼是因其营养的全面才如此有益，”英国斯特灵大学水产养殖研究所的营养学讲师马修·斯普拉格表示。

Is one type healthier than another?
不同三文鱼的营养价值也不同？

“There are so many different options in the marketplace, it can be confusing,” said Stefanie Colombo, an associate professor and research chair in aquaculture nutrition at Dalhousie University in Canada.
“市面上的选择实在太多，可能会造成困惑，”加拿大达尔豪斯大学副教授兼水产养殖营养学研究主任斯蒂芬妮·科伦坡表示。

In an attempt to clear up some of that confusion, Dr. Colombo examined the nutritional values of the types of salmon available to consumers. “The main finding of our work was that there’s not much difference between wild and farmed,” she said.
为了消除这些困惑，科伦坡研究了可供消费者食用的各类三文鱼的营养价值。“野生和养殖三文鱼没有太大差别，这是我们研究的主要发现，”她说。

While wild sockeye and wild chinook — two of the most commonly sold species — were the most “nutrient dense,” her study also found that farmed Atlantic salmon only had slightly lower levels of omega-3s, proteins and other healthful nutrients. Wild Pacific pink salmon tended to have less of these nutrients than the other types, regardless if they were farmed or wild.
虽然野生红鲑和野生帝王鲑这两种市面上最常售的品种最“富含营养”，但她的研究还发现，养殖的大西洋三文鱼中Omega-3脂肪酸、蛋白质和其他健康成分的含量只是略低一些。野生太平洋粉红三文鱼的这些营养成分的含量往往比其他品种——无论是养殖还是野生——都要低。

The nutritional figures in Dr. Colombo’s study were averages, however. Depending on factors such as the type of feed given to farmed salmon, or the time of year a wild salmon is caught, she said, the levels of healthy fats or other nutrients can differ from fish to fish.
但科伦坡研究的营养数据都是平均值。她说，根据养殖三文鱼的饲料种类和一年中野生三文鱼的捕捞时间等因素，不同品种三文鱼的健康脂肪或其他营养成分可能有所不同。

Dr. Colombo added that “all the salmon we looked at was very nutritious.”
科伦坡还补充道，“我们研究的所有三文鱼都非常有营养。”

What about mercury and other contaminants? Dr. Colombo said her paper did find some differences among types: Farmed Atlantic salmon, for example, tended to have lower mercury levels than wild-caught varieties. However, all the samples contained levels of mercury far below international safety standards. “Even if you ate salmon every day, mercury is not something you should be concerned about,” she said.
至于汞和其他污染物，科伦坡称其论文的确发现了不同品种间的一些差异。例如，养殖的大西洋三文鱼的汞含量往往低于野生品种。不过，所有三文鱼样本的汞含量都远低于国际安全标准。“哪怕每天都吃三文鱼，也不用担心汞中毒，”她说。

The same can be said for polychlorinated biphenyls (PCBs) and other contaminants that sometimes turn up in seafood. Research has found that salmon, whether wild or farmed, does not contain harmful levels of these toxins. That’s partly because it doesn’t live long enough to absorb a lot of them, Dr. Mozaffarian said. 多氯聯苯(PCB)和海鲜中有时含有的其他污染物也是如此。研究发现，不管是野生的还是养殖的三文鱼，这些毒素都没有达到有害水平。莫扎法里安说，部分原因在于三文鱼寿命没有长到能大量吸收这些毒素的地步。

For those concerned about the ecological impact of their food choices, salmon comes with some baggage; both the overfishing of wild species and farming-related pollutants are ongoing concerns. But experts said that all types of salmon outperform most animal sources of protein, in terms of environmental footprint.
对那些很在意饮食选择会影响生态的人来说，食用三文鱼会带来一些心理负担：野生鱼类的过度捕捞和养殖造成的污染一直都是令人担忧的问题。但专家表示，就环境足迹而言，所有三文鱼品种都优于大多数动物性蛋白质来源。

When buying salmon, Dr. Colombo recommended looking for label certifications from the Marine Stewardship Council (MSC) or Best Aquaculture Practices (BAP). “If the salmon is certified, that should give you more confidence it has been sustainably and ethically sourced,” she said.
科伦坡建议选购带有海洋管理委员会(MSC)或最佳水产养殖规范(BAP)认证标签的三文鱼。“如果是有认证的三文鱼，那就可以对其来源的可持续性和守德性更有信心，”她说。

Above all, the experts affirmed that all salmon is good for you, and agonizing over a choice isn’t necessary: “Assuming you like the flavor,” Dr. Mozaffarian said, “it’s really the perfect fish.”
最重要的是，专家们都已确认所有三文鱼均有益健康，因此没有必要纠结于选哪种才好。“假如你喜欢某种三文鱼的风味，”莫扎法里安说，“那它就是最适合你的三文鱼了。”

翻译：Nic Wong