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Fish Oil Supplements: A Fish Tale or a Good Catch?[1]

魚油補品：真的假的？

If you take a handful of supplements every morning, chances are fish oil is among them.

如果你是每天早上都會吃些保健食品的人，這些保健食品之中可能也會包含魚油。

The global value of the fish oil market is expected to surpass $4 billion by 2022. Enthusiasts say it can help with age-related macular degeneration, rheumatoid arthritis pain, high cholesterol, asthma, depression, ADHD, heart disease, and may even help you get gorgeous hair.

全球魚油市場的價值預計將在2022年超過40億美元。魚油愛好者會說魚油能夠緩解老年性黃斑部病變、類風濕性關節炎疼痛、高膽固醇、氣喘、憂鬱症、注意力不足過動症、心臟病等疾病，甚至還可以讓人擁有一頭亮麗的秀髮。

If that all sounds too good to be true, well, you know. …

如果覺得這些好處好得令人難以置信，額嗯……你懂的……

But before you throw out your fish oil like 3-day old fish, get the facts. It may have some benefits for your heart, your joints, and your brain. But there are caveats.

不過，在你像扔掉放了三天的魚那樣扔掉這些魚油之前，還是先了解一些關於魚油的真相吧。魚油對心臟、關節和大腦還是有些好處的，不過在吃魚油之前還有一些事項要先注意。

 

What Is Fish Oil?

什麼是魚油？

Doctors and scientists first took notice of fish oil when research revealed that cultures that ate more fish -- Scandinavians and Inuits, for example -- had lower rates of heart disease. Many types of fish, including salmon, mackerel, herring, lake trout, sardines, and albacore tuna, contain omega-3 fatty acids -- a healthy type of fat. Two of the most important omega-3s in fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Researchers wanted to know whether taking fish oil straight -- without eating fish -- might help the heart.

當研究顯示一些吃魚吃比較多的地區，像是斯堪地那維亞人和因紐特人，他們患有心臟病的比率比較低後，醫生和科學家們才開始注意到魚油的作用。許多類型的魚，包括鮭魚、鯖魚、鯡魚、湖鱒、沙丁魚和長鰭鮪，都含有omega-3脂肪酸，這是一種健康的脂肪。魚類含有的omega-3脂肪酸以二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）為最重要的兩種。研究人員一直都想知道只吃魚油，而不吃魚，對心臟有沒有好處。

“In clinical trials, the results are very mixed,” says J.L. Mehta, MD, PhD, a cardiologist and professor at the University of Arkansas for Medical Sciences in Little Rock. “Some show benefits. Many do not.”

阿肯色大學小石城分校醫學院的心臟病專家兼教授梅塔博士說：「臨床試驗的結果非常複雜，一部分的結果還不錯，但是大部分都沒有得出太好的結果。」

 

Why the Mixed Reviews?

為什麼對魚油的評論褒貶不一？

Early tests showed that fish oil helped the heart in many ways, but researchers have scratched their heads when more recent studies didn’t get the same results.

早期的測試都顯示魚油在各方面對心臟有好處，不過之後的研究卻無法產生相同的結果，使得研究人員摸不著頭緒。

“This may be because there are so many medications that are now being used to treat high-risk patients. A very large percentage are on aspirins, statins, beta-blockers, ACE inhibitors, and this may obscure the role of a dietary supplement like omega-3s,” says JoAnn Manson, MD, chief of preventive medicine at Brigham and Women’s Hospital in Boston.

波士頓伯明罕婦女醫院預防醫學中心的主任曼森博士說：「這可能是因為現在有許多藥物都能用來治療高危患者。現今使用阿司匹林、他汀類藥物、乙型阻斷劑、ACE(血管收縮素轉化酶)抑制劑的比例非常大，所以可能因此減少了保健食品(如omega-3脂肪酸)的作用。」

It may also be that Westerners eat more fish today than they once did because they’ve heard it’s good for them, so a supplement wouldn’t help.

也可能是因為西方人聽說了吃魚的好處，所以現在吃得比以前還多，使保健食品無法發揮功效。 

Different studies also use different fish oil doses and formulations -- whether they are equal parts EPA and DHA or heavier on one than the other.

不同的研究也使用不同的魚油劑量和配方，無論EPA和DHA的比例是相同的，還是其中一項的比例比較高都有。

 

The Evidence for Fish Oil

魚油有效的證明

If you’ve already had a heart attack or are at a high risk of having one …

如果你是有過心臟病發作的經驗或是高風險的人......

Large prescription-strength doses of pure EPA -- not the type you buy off the shelf at the drugstore -- can help the hearts of people who have certain conditions that make heart problems more likely. Prescription fish oils lower triglycerides -- a type of fat that circulates in the bloodstream. A recent study showed that 4 grams of pure EPA per day for 5 years significantly cut the risk for heart attack, stroke, bypass, chest pain, and death from sudden cardiac arrest during that time.

對於患有對心臟影響比較大的疾病的人而言，適合服用高劑量的純EPA，而不是那種在藥局就可以買得到的魚油。藥品級魚油能夠降低三酸甘油脂，三酸甘油脂是一種在血液中循環的脂肪。近期的一項研究顯示，5年內每天服用4公克的純EPA能夠顯著地降低心臟病發作、中風、繞道手術、胸痛和死於心臟驟停的風險。

But it’s worth noting that the people who saw these benefits already had a host of heart-related health problems. Their LDL, or “bad,” cholesterol and triglycerides were high even though they took cholesterol-lowering medications. They also already had heart disease, or they had diabetes and at least one other thing that made heart disease more likely.

不過值得注意的是，那些能夠看到上述好處的人本身卻已有不少和心臟有關的健康問題。像是即使有在吃降膽固醇的藥，他們的低密度脂蛋白(LDL)，或是「壞」膽固醇和三酸甘油脂還是很高。這些人本身也都有心臟病或是糖尿病，和至少一種可能會導致心臟病的疾病。

For people who’ve never had a heart attack and run a normal risk of ever having one, says Manson, “it’s unlikely that 4 grams a day would be recommended. There’s a threshold at which you’d stop seeing benefits.”

對於沒有心臟病發作過的人和一般大眾而言，曼森說：「是不太建議每天服用4公克的量。因為魚油所能產生的效果也是有門檻的，超出了這個門檻就不會再產生任何好處了。」

A similar study found that a prescription form of 1.8 grams of EPA per day, in addition to a cholesterol-lowering medication, cut the odds of having heart attacks and other heart problems in people who had high cholesterol. Many of them also had heart disease, diabetes, and/or high blood pressure. Although 1.8 grams is a lot less EPA than 4 grams, the study participants, who were Japanese, already got more fish oil directly from the fish in their regular diet than Westerners do.

有一項類似的研究發現，對於有高膽固醇的人而言，除了吃降膽固醇的藥之外，若每天依處方服用1.8公克的EPA的話，可以減少心臟病發作和其他心臟疾病的機率。這項研究的參與者大多還患有心臟病、糖尿病和/或高血壓。雖然1.8公克的EPA比4公克少很多，不過這些研究參與者都是日本人，比起西方人，他們已經直接在日常飲食中靠吃魚攝取更多魚油了。

So, exactly how much is 1.8 grams of EPA? Remember the cereal commercial that said “You’d have to eat four bowls of Raisin Bran to get the vitamin nutrition in one bowl of Total?” Well, you’d have to take 10 capsules -- five servings -- of an average over-the-counter fish oil supplement to get 1.8 grams of EPA. Want the full four grams? You’ll need to take about 22 capsules. And no one is recommending that. Studies that show benefits of high doses of EPA use prescription-grade pure EPA. Over-the-counter supplements have other ingredients, too, and they are not regulated and safety-tested like FDA-approved prescription drugs.

所以1.8公克的EPA到底是多少？還記得有個麥片廣告說的嗎？「一碗Total中所含的維生素營養相當於四碗Raisin Bran的營養。」這樣說吧，1.8公克的EPA 相當於10粒(5份)非藥品級魚油膠囊。若想吃滿四公克的話，那得吃下大概22粒的膠囊。沒有人會這樣吃的。所有結果顯示服用高劑量EPA有好處的研究都是使用藥品級的純EPA。非藥品級食品中還會添加其他成分，而且這些保健食品也不像經美國食品藥品監督管理局批准的處方藥一樣，有受到監管和通過安全測試。

“Some people take multiple, multiple capsules. But we don’t know that that’s safe,” says Manson. “Unless that’s under the guidance of a clinician, avoid mega-dosing.”

曼森說：「有些人會吃下一大堆膠囊，可是目前還不知道這樣吃安不安全，所以除非是在臨床醫生的指導下服用，否則最好是避免服用大劑量的魚油。」

 

If your heart’s already pretty healthy …

如果你的心臟已經相當健康了......

In lower doses, fish oil may help the hearts of people who are in pretty good health. In a study of 25,871 adults over 50 with an average risk for heart attack, the ones who took 1 gram of fish oil -- containing 460 mg EPA and 380 mg DHA (just a little more than you might find in a daily OTC dose) -- every day for 5 years had a 28% lower risk for heart attack during that time. But they didn’t have a lower risk of stroke or death from heart disease. In fact, many studies that aimed to prove ordinary fish oil supplements lower risk for heart disease have failed to do so.

對於健康狀況良好的人而言，服用低劑量的魚油對心臟的幫助就已經足夠了。有一項研究是針對50歲以上，具有一般罹患心臟病風險的成年人，共25,871名所進行的實驗，它讓參與者連續五年每天服用1公克的魚油，其中包含460毫克的EPA和380毫克的DHA（這個劑量只比每天服用非處方藥的劑量還要再多一點點），5年內，參與者心臟病發作的風險降低了28％，不過中風或死於心臟病的風險卻沒有減少。實際上，有不少想要證明一般魚油補品能夠降低心臟病風險的研究都以失敗收場。

 

If it’s not your heart you’re worried about …

如果你擔心的不是心臟的話......

Aside from heart health, researchers have studied the effects of fish oil on many other conditions. But the benefits are clear in only a few of them. Fish oil might relieve symptoms of rheumatoid arthritis and lessen the need for pain medications, but only a little, the research shows. And in people who have a higher than average risk of getting Alzheimer’s disease because they carry the APOE ε4 gene mutation, high doses of DHA before symptoms of the disease arise may make having the condition less likely.

除了對心臟健康的研究之外，也有研究是探討魚油對其他各種疾病的影響，不過魚油的好處只體現在少數幾個疾病上而已。研究顯示，魚油可以減輕類風濕性關節炎的症狀，減少對止痛劑的需求，不過這個功效卻不大。帶有APOE-ε4基因型的人患有阿茲海默症的風險會高於一般人，對他們而言，若能在症狀出現之前服用高劑量的DHA，或許可以使患病的機率降低。

As for other conditions, the benefits of fish oil are either nonexistent or unclear.

至於其他的疾病，魚油要嘛就是沒用，要嘛就是好處不明顯。

 

Can’t I Just Eat Fish?

我不能就只吃魚嗎？

Absolutely. The best way to get most any nutrients, including omega-3s, is from your diet. In fact, several studies that show no benefits of fish oil supplements do show benefits of eating fish. For example, while fish oil supplements don’t lower the risk of heart disease, studies show that people who eat fish one to four times a week are less likely to die of heart disease than those who rarely or never do. Eating fish and shellfish may cut risk for stroke and for the loss of memory and thinking skills that can lead to dementia.

當然可以。最好的營養攝取方式就是從日常飲食中攝取包括omega-3脂肪酸在內的各種營養素。事實上，許多表示吃魚油補品沒有好處的研究，卻都說吃魚有各種好處。例如，雖然吃魚油補品不會降低心臟病的風險，但是研究顯示，每週吃一至四次魚的人死於心臟病的可能性比那些很少或從未這樣吃的人還低。吃魚類和貝類可以降低中風的風險，也可以降低失憶和失去思考能力這種會導致失智症的症狀產生的風險。

What’s more, in studies that do show benefits of fish oil supplements, those benefits may be less in people who already eat plenty of fish and more in people who don’t get enough fish.

此外，在那些顯示吃魚油補品有好處的研究中，對於那些已經吃了大量魚類的人來說，魚油補品的好處比較不明顯，而在那些魚類吃得不夠多的人身上，好處就比較明顯。

“If there’s a rock-solid reason to supplement, then it’s to fulfill nutrient shortfalls for people who don’t consume enough fish,” says Duffy MacKay, ND, who is senior vice president for scientific & regulatory affairs at the Council for Responsible Nutrition, a trade association that represents dietary supplement manufacturers and ingredient suppliers.

可靠營養品協會的科學與醫藥法規高級副總裁杜芬·邁凱伊說：「若真要找出一個必吃不可的理由，那麼就是魚油補品是用來幫那些吃魚吃不夠的人解決營養不足的問題。」這是一個保健食品生產商與原料供應商的貿易協會。

For example, take the study that showed that 1 gram of fish oil per day lowered the risk for heart attacks. That was true only for people who didn’t already eat fish. The researchers divided the study participants into two groups -- those who ate less than a serving and a half of fish per week, and those who ate that much or more. The ones who ate the least fish had a 19% drop in heart attack, stroke, and heart disease death, and a 40% drop in heart attack risk when they took the supplement.

例如，以那個結果顯示每天服用1公克魚油能降低心臟病發作風險的研究為例。這個結果只對那些不吃魚的人而言才有效。這項研究將參與者分為兩組：一組的人每週吃不到一份半的魚；另一組的人每周至少吃到這個量的魚。吃魚吃最少的那組在服用魚油補品後，心臟病發作、中風和死於心臟病的情形下降了19％，而心臟病發作的風險下降了40％。

“They didn’t already have sufficient fish intake and weren’t already at a threshold where the supplements would have no additional benefit. If they were above 1.5 servings a week, they did not have a clear benefit,” Manson says.

曼森說：「這組人沒有攝取足夠的魚類，也尚未達到不管吃再多補品都不會再產生額外好處的門檻。如果他們每週都能吃超過1.5份的魚類，那麼吃補品就無法再產生明顯的好處。」

 

What’s the Bottom Line for Over-the-Counter Fish Oil?

對非處方魚油的基本要求是什麼？

“Fish oil is not a magic cure-all, but the fact that the evidence is solid in a couple areas shows it is an important nutrient,” says MacKay.

邁凱伊說：「雖然魚油不是萬靈丹，但是在不少地區都證實魚油確實有效，這也表明魚油是一項重要的營養素。」

If you’re already taking fish oil at a recommended over-the-counter dose, and you’re doing well on it, there’s no research that says you should stop. But don’t take any more than that. There’s no proof that’s safe or helpful.

如果你目前是依照建議劑量服用非處方魚油，而且感覺不錯的話，也不一定要停止服用，可是，千萬不要超過這個劑量，因為目前為止還沒有任何證據證明吃過多的魚油對人體有好處。

If you’re not taking fish oil, try to get it from your plate first. The American Heart Association recommends two servings -- that’s about 7 ounces -- of fish a week. Preferably the fatty kind that’s rich in omega-3s.  

如果目前沒有吃任何魚油的話，就先試著直接吃魚吧。美國心臟協會建議每週吃兩份(約7盎司)的魚。最好是吃富含omega-3脂肪酸的魚。

If you want to start taking fish oil, talk to your doctor about side effects and any interactions it might have with medications you already take. The most common side effects, which 1% to 10% of people have, include belching, indigestion, nausea, bloating, belly pain, constipation, diarrhea, gas, acid reflux, and vomiting. If you take blood thinners, blood pressure-lowering medications, contraceptives, the weight loss drug orlistat (sold as Alli and Xenical), or vitamin E, talk to your doctor about interactions that could be dangerous before starting fish oil.

如果你想開始吃魚油的話，先和醫生討論一下副作用的問題以及魚油可能會和你目前正在服用的藥物產生哪些相互作用。有1%-10％的人會出現副作用，最常見的副作用有噯氣、消化不良、噁心、脹氣、腹痛、便秘、腹瀉、排氣、胃酸逆流和嘔吐。有在服用血液稀釋劑、降血壓藥、避孕藥、減肥藥orlistat（商品名為康纖伴和羅氏鮮）或維生素E的人，在開始吃魚油之前，要先和醫生討論可能會產生哪些有害的相互作用。