What is MSG, and is it actually bad for you? - Sarah E. Tracy

譯者: Lilian Chiu 審譯者: Amanda Zhu

In 1968, Dr. Robert Ho Man Kwok felt ill after dinner at a Chinese restaurant.

1968 年，

郭浩民醫生在中國餐廳 吃過晚餐之後感到不適。

He wrote a letter detailing his symptoms to a prestigious medical journal,

他寫信給一份很有名望的醫學期刊， 說明他的症狀細節，

pondering whether his illness had resulted from eating monosodium glutamate—

懷疑他的不適是不是因為 吃了麩胺酸鈉，

also known as MSG.

也就是味精。

Kwok’s connection between his headache and this common seasoning

郭醫生認為他的頭痛

和這種美國中式料理 常用調味料有關，

in American Chinese cuisine was just a hunch.

但這只是出於直覺。

But his letter would dramatically change the world's relationship with MSG,

但他的信卻大大改變了 世界和味精的關係，

inspiring international panic, biased science,

不但引起國際恐慌，

並助長了偏頗的科學及聳動的新聞，

and sensationalist journalism for the next 40 years.

影響持續四十年之久。

So what is this mysterious seasoning?

所以這種神秘的調味料是什麼？

Where does it come from, and is it actually bad for you?

它從何而來？對人體真的不好嗎？

MSG is a mixture of two common substances.

味精是由兩種簡單的成分組成：

鈉，已公認是飲食中 很重要的一部分；

Sodium, which is well-established as an essential part of our diet,

and glutamate, a very common amino acid

以及麩胺酸，很常見的胺基酸，

found in numerous plant and animal proteins.

在許多植物和動物蛋白質中都有。

Glutamate plays a key role in our digestion, muscle function,

在我們的消化、 肌肉功能，及免疫系統中，

麩胺酸鹽都扮演了關鍵的角色。

and immune system.

Around the time of Dr. Kwok's letter,

在郭醫生寫信的那個時期，

麩胺酸鹽一直被視為 腦部化學機制的重要元素。

it had been identified as an important part of our brain chemistry.

Our body produces enough glutamate for all these processes,

我們的身體會產生足夠的麩胺酸鹽 來應付這些生化反應，

but the molecule is also present in our diet.

但這種能加強食物風味的分子

也會出現在我們的飲食中，

You can taste its signature savory flavor in foods

包括香菇、起士、蕃茄、高湯。

like mushrooms, cheese, tomatoes, and broth.

對這種豐富口味的追求， 在 1908 年促成了味精的發明。

Chasing this rich flavor is what led to MSG’s invention in 1908.

日本化學家池田菊苗

A Japanese chemist named Dr. Ikeda Kikunae

was trying to isolate the molecule responsible for a unique flavor

試圖將這種口味獨特的分子分離出來，

他稱此味為「旨み」（旨味）， 意即「鮮美的味道」。

he called “umami,” meaning “a pleasant, savory taste.”

Today, umami is recognized as one of the five basic tastes in food science.

現今，在食物科學中，

旨味被視為五種基本口味之一。

每一種基本口味都是由 專屬的分子機制產生，

Each basic taste is produced by unique molecular mechanisms

that can’t be replicated by combining other known tastes.

無法透過混合其他已知的味道來複製。

至於旨味，

In the case of umami,

those mechanisms arise when we cook or ferment certain foods,

某些食物在烹煮或發酵時， 就會產生那些機制，

分解其中的蛋白質，

breaking down their proteins and releasing amino acids like glutamate.

釋放出胺基酸，比如麩胺酸。

但池田發現了一種 可以產生這種化學反應的美味捷徑，

But Ikeda found a savory shortcut to producing this chemical reaction.

By isolating high quantities of glutamate from a bowl of noodle broth

做法是從一碗拉麵高湯中 分離出大量的麩胺酸，

把它們和另一種 味道強化劑結合，比如鈉，

and combining them with another flavor enhancer like sodium,

如此創造出的調味料

he created a seasoning that instantly increased the umami of any dish.

能馬上在任何菜餚中增加旨味。

結果大獲成功。

The result was a major success.

By the 1930s, MSG was a kitchen staple across most of Asia;

到了 1930 年代，味精成了 亞洲多數地區的廚房必備調味料；

and by the mid-20th century,

到了二十世紀中，

it could be found in commercial food production worldwide.

它已經被用於世界各地的 商業食品製造。

所以，郭醫生的信件刊登出來後，

So when Dr. Kwok's letter was published, the outrage was immediate.

馬上引發眾怒。

Researchers and citizens demanded a scientific enquiry

研究者和人民要求

對這種廣為使用的 添加物進行科學調查。

into the popular additive.

On one hand, this wasn’t unreasonable.

一方面，這並非不合理。

這種物質尚未經毒性檢測，

The substance hadn't been tested for toxicity,

它對健康的影響也多半未知。

and its health impacts were largely unknown.

However, it’s likely many people weren’t responding

不過，讓大部分人反彈的

to a lack of food safety regulation,

並不是缺乏食物安全法規，

而是信件的標題： 「中國餐館症候群」。

but rather the letter’s title: “Chinese Restaurant Syndrome.”

雖然很多菜餚都會用到味精，

While MSG was commonly used in numerous cuisines,

許多美國人長年來

many Americans had longstanding prejudices against Asian eating customs,

對亞洲人的飲食習俗都存有偏見，

為之貼上異國或危險的標籤。

labeling them as exotic or dangerous.

這些污名激起了 帶有種族偏見的新聞報導，

These stigmas fueled racially biased journalism,

並散播恐懼，

and spread fear that eating at Chinese restaurants could make you sick.

讓大家認為在中國餐館 用餐就會生病。

這些有偏見的報導延伸出 許多關於味精和旨味的研究，

This prejudiced reporting extended to numerous studies about MSG and umami,

研究結果完全不像 新聞標題暗示的那麼肯定。

the results of which were much less conclusive than the headlines suggested.

For example, when a 1969 study found that injecting mice with MSG

舉例來說，

一項 1969 年的研究發現， 將味精注射到老鼠身上

會對牠們的視網膜和腦部 造成嚴重傷害，

caused severe damage to their retina and brain,

有些新聞管道就因此武斷地宣稱，

some news outlets jumped to proclaim that eating MSG could cause brain damage.

吃下味精會造成大腦損傷。

Similarly, while some studies reported that excess glutamate

同樣地，雖然有些研究 指出過量的麩胺酸鹽

could lead to problems like Alzheimer’s,

可能會造成阿茲海默症等問題，

these conditions were later found to be caused by internal glutamate imbalances,

後來發現這些病症的成因

是體內麩胺酸鹽不平衡，

和我們吃下的味精無關。

unrelated to the MSG we eat.

These headlines weren't just a product of prejudiced reporters.

不僅存有偏見的記者 會下這樣的標題，

Throughout the late 60s and early 70s,

1960 年代末，1970 年代初，

many doctors also considered “Chinese Restaurant Syndrome”

許多醫生也認為「中國餐館症候群」

to be a legitimate ailment.

的確是一種疾病。

Fortunately, today’s MSG researchers no longer see the additive

幸運的是，

現今的味精研究者不再用歧視的眼光

看待這種添加物。

in this discriminatory way.

近期的研究確認了麩胺酸鹽

Recent studies have established the vital role glutamate plays in our metabolism,

在我們的新陳代謝中 扮演重要的角色，

有些研究者甚至認為， 味精可以替代脂肪和納來增添美味，

and some researchers even think MSG is a healthier alternative

而且還更健康。

to added fat and sodium.

Others are investigating whether regular consumption of MSG

也有研究者在探究

經常吃味精是否和肥胖有關，

could be linked to obesity,

and it is possible that binging MSG produces headaches,

以及大量食用味精

是否可能讓某些人產生 頭痛、胸痛或心悸的症狀。

chest pains, or heart palpitations for some people.

但對多數的食客，

But for most diners, a moderate amount of this savory seasoning

適量吃入這種可口的調味料 還蠻安全的，

seems like a safe way to make life a little tastier.

也可以讓人生更美味。