孕婦吃金槍魚究竟安全嗎

For years pregnant women have been warned about eating tuna because of concerns about mercury exposure. But a federal panel has reignited the debate about the benefits and risks of eating tuna and other seafood during pregnancy.

多年來，因爲汞污染問題，孕婦一直被警告不宜食用金槍魚。然而，聯邦政府的一個顧問小組最近卻就妊娠期食用金槍魚等海產品的風險和收益，重新挑起了爭論。

Experts agree that seafood is a rich source of important nutrients, and that most of us don’t eat enough of it. Fish is rich in omega-3 fatty acids, B vitamins, iodine, selenium and vitamin D. And numerous studies show that the nutrients in fish are particularly important for brain development in fetuses and nursing infants.

專家們一致認爲海產品是重要營養物質的豐富來源，且我們大多數人的海產品攝入量都不足。魚肉中富含ω-3脂肪酸、B族維生素、碘、硒和維生素D。衆多研究表明，魚肉中的營養物質對於胎兒和哺乳期嬰兒的大腦發育尤爲重要。

As part of a sweeping review of nutrition recommendations, the Dietary Guidelines Advisory Committee recently reiterated the current seafood guidelines: Americans should eat a wide variety of seafood. The report also acknowledges the risk of mercury exposure from certain kinds of seafoods, and notes that women who are pregnant, nursing or may become pregnant should avoid certain kinds — tilefish, shark, swordfish and king mackerel — because of their high mercury content.

此次對營養建議的全面複審由美國膳食指南諮詢委員會(Dietary Guidelines Advisory Committee)負責。作爲這項工作的一部分，該小組最近重申了當前的指南：美國人應食用多種多樣的海產品。其報告承認某些種類的海產品存在汞暴露風險，並指出孕婦、哺乳期或備孕女性應避免食用某些汞含量偏高的魚類：方頭魚、鯊魚、箭魚和王鯖。

The panel withheld a recommendation about tuna, second only to shrimp in popularity in the United States. Current guidelines from the Food and Drug Administration and the Environmental Protection Agency warn pregnant and nursing women to limit tuna consumption to six ounces per week.

但是，該小組並不贊同關於金槍魚，也就是美國僅次於蝦的第二受歡迎的海產品的建議。美國食品和藥品監督管理局(Food and Drug Administration)和美國國家環境保護局(Environmental Protection Agency)的現行指南警告：孕婦和哺乳期婦女應將金槍魚的攝入量限制在每週6盎司（約合170克）。

The advisory committee has recommended that these agencies “re-evaluate” their stance on tuna for pregnant women. In the report, the panel argues that albacore tuna is a “special case.” They noted that even when women ate double the recommended weekly amount of tuna, the benefits far outweighed the risks. “All evidence was in favor of net benefits for infant development and (cardiovascular disease) risk reduction,” the panel wrote.

諮詢委員會建議上述機構“重新評估”他們在孕婦食用金槍魚問題上的立場，並在報告中指出：長鰭金槍魚應作爲一個“特例”。即使婦女食用每週建議量兩倍的金槍魚，其淨收益也遠遠大於風險。“所有的證據都支持它有益於嬰兒發育，並可降低（心血管疾病）的風險。”

The suggestion that pregnant women can eat more white albacore tuna — the type of tuna typically used in canned tuna — has upset advocacy groups that have called for increased warnings about mercury on tuna packaging.

顧問小組表示孕婦適當多吃些白長鰭金槍魚（常用於製作金槍魚罐頭）也無妨，這令大聲疾呼應對包裝金槍魚食品的汞污染提高警惕的宣傳組織十分不滿。

“Tuna is responsible for nearly seven times more mercury exposure than the four high-mercury fish that the Federal Food and Drug Administration advises pregnant women not to eat,” said Michael Bender, director of the mercury policy project, in a statement. “So why would the proposed 2015 dietary guidelines recommend that pregnant women eat more of it?”

“金槍魚中的汞污染是美國食品和藥品監督管理局建議孕婦不要食用的四種高汞魚類的近七倍，”汞政策項目”(mercury policy project)的負責人邁克爾·本德爾(Michael Bender)在一份聲明中稱。“那麼，又爲何提出在2015年的膳食指南中建議孕婦多吃金槍魚？”

But Dr. Steve Abrams, a panel member involved in the seafood recommendations and medical director of the Neonatal Nutrition Program at Baylor College of Medicine, said that while women need to be aware of the types of fish they are eating, the evidence is strong that fish consumption by mothers is good for the brains of their babies.

但是，參與制定海產品膳食建議的顧問小組成員、美國貝勒醫學院(Baylor College of Medicine)新生兒營養項目(Neonatal Nutrition Program)主任史蒂夫·艾布拉姆斯(Steve Abrams)博士表示，雖然婦女需要對自己食用的幾種魚類多加註意，但強有力的證據顯示母親食用魚肉對嬰兒的大腦有好處。

“The goal of the dietary guidelines is to give people a healthy way to eat and not to include or exclude certain foods,” said Dr. Abrams. “The benefit of having (omega-3 fatty acids) in your diet really exceeds the likely risk of contamination. The point is that you should have a variety of types of seafood and not limit yourself to one type, and variety includes canned tuna.”

“膳食指南的目的在於指導人們以健康的方式飲食，而不是將某些食物納入或排除出食譜，”艾布拉姆斯博士說。“膳食中加入含（ω-3脂肪酸）的食物帶來的收益大大超過了可能的污染風險。問題的關鍵是，你應該食用包括金槍魚罐頭在內的多種的海產品，而不是侷限於某一特定種類。”

Alice Lichtenstein, senior scientist and director of the Cardiovascular Nutrition Laboratory at Tufts University said the panel hasn’t suggested that pregnant women eat more tuna. “The issue of fish contamination is a moving target and you need very current data,” said Dr. Lichtenstein. “It may be that the issue is re-evaluated and there is no change.”

塔夫茨大學(Tufts University)心血管營養實驗室(Cardiovascular Nutrition Laboratory)主任、資深科學家艾麗斯·利希滕斯坦(Alice Lichtenstein)表示，該小組並未建議孕婦多吃金槍魚。“魚肉污染的情況無時無刻不在發生變化，需要研究即時的數據，”利希滕斯坦博士說。“很可能，在重新評估過該問題後，發現無需做出改變。”

Mercury levels in our oceans are on the rise due to an increase in industrial mercury emissions. Plants, plankton and tiny fish that have absorbed small amounts of mercury are eaten by larger fish. Over time, large fish sharks and swordfish accumulate high levels of mercury. As a result, health officials recommend fish like sardines, salmon, tilapia and trout that are lower on the food chain and have accumulated less mercury in their tissue.

工業汞排放的增加造成海洋中的汞含量持續上升。植物、浮游生物和小魚體內都吸收了少量的汞，而它們又是大魚的口中餐。隨着時間的推移，鯊魚和箭魚等大型魚類體內就積累了高濃度的汞。因此，衛生官員建議人們食用位於食物鏈較低位置，組織中積累汞含量較少的魚類，如沙丁魚、鮭魚、羅非魚和鱒魚等。

The benefits of fish consumption on a developing fetus are clear. In a Harvard study of 135 mothers and infants, researchers tracked fish consumption during pregnancy and tested the mother’s hair to measure her mercury exposure. They found that for each weekly serving of fish the mother ate while pregnant, her baby’s score on visual recognition memory tests increased an average of four points. At the same time, a baby’s score dropped by 7.5 points for every one part per million increase in mercury found in the mother’s hair sample. The babies who scored highest on the memory tests were those whose mothers had consumed two or more servings of fish each week during their pregnancy, but were tested to have very low mercury levels.

食用魚肉對發育中的胎兒的益處顯而易見。在哈佛大學(Harvard)的一項研究中，科學家們以135對母嬰爲研究對象，跟蹤了母親在妊娠期食用魚肉的情況，並檢測了母親的頭髮以測定其汞暴露程度。他們發現，孕婦每食用一週份的魚肉，日後其孩子在視覺識別記憶測試中的得分平均將增加四分。同時，母親頭髮樣本中的汞含量每增加一百萬分之一(p.p.m.)，她孩子的上述得分就會降低7.5分。當母親在妊娠期間每週至少食用兩份魚肉，頭髮檢測出的汞濃度又非常低時，孩子在記憶測試中得分最高。

Health officials have long worried about balancing warnings about mercury against the obvious benefits of consuming more fish. Currently fewer than one in five Americans eats the recommended two servings a week of fish. About one-third eat one serving of seafood weekly and nearly half of us eats very little seafood or none at all.

長久以來，衛生官員在究竟是強調多吃魚好處多多還是警惕汞攝入量之間，舉棋不定。目前，只有不到五分之一的美國人遵照建議每週食用兩份魚肉。約三分之一的人每週食用一份海產品，近一半人僅食用很少或根本不食用海產品。

This fall Consumer Reports issued a lengthy paper on fish and mercury exposure, noting the special concerns about canned tuna due to its popularity. Six ounces of canned tuna contains 60 micrograms of mercury compared to just 4 micrograms of mercury in a six-ounce serving of salmon, according to Consumer Reports. (A six-ounce serving of swordfish contains 170 micrograms, the magazine said. )

去年秋天的時候，《消費者報告》(Consumer Reports)發表了關於魚類和汞暴露的長篇文章，並對廣受歡迎的金槍魚罐頭表示了特別關注。《消費者報告》稱，6盎司金槍魚罐頭中含有60微克的汞，相比之下，一份6盎司的鮭魚中汞含量只有4微克。（該雜誌還稱，一份6盎司的箭魚中含有170微克的汞。）

For people who want to safely eat more seafood, the magazine recommended shrimp, scallops, sardines, salmon, oysters, squid and tilapia as the lowest-mercury seafood. Also low are haddock, pollock, flounder and sole, Atlantic croaker, crawfish, catfish, trout, Atlantic mackerel, crab and mullet. In addition to the usual warnings about high mercury fish, Consumer Reports added marlin and orange roughy to the list. They suggested limiting consumption of grouper, Chilean sea bass, bluefish, halibut, black cod, Spanish mackerel and fresh tuna.

雜誌建議，如果想要放心地食用較大量的海產品，可選擇蝦、扇貝、沙丁魚、鮭魚、牡蠣、魷魚和羅非魚等汞含量最低的海產品。其他汞含量較低的品種有：黑線鱈、青鱈、比目魚和鰨、細須石首魚、小龍蝦、鮎魚、鱒魚、大西洋鯖魚、蟹和鯔魚。高汞魚類的警告列表中，除了常見的那幾種之外，《消費者報告》又補充了馬林魚和大西洋胸棘鯛。建議有限制地食用的魚類有：石斑魚、智利海鱸魚、扁鰺、星鰈、銀鱈、馬鮫魚和新鮮金槍魚。