Most individuals, yes, that includes you, will make anywhere from 500-1500 milliliters of gas,

大部分的人，是的，包含你，會製造出500-1500毫升的氣體。

and can pass gas ten to twenty times a day.

且每天會排放10至20次。

But where does this bodily gas come from?

但這身體產生的氣體是怎麼來的？

A small proportion may come from ingesting air during sleep, or at other times,

有一小部分是來自睡眠時，或其他時候吸收的氣體。

but the majority of gas is produced by bacteria in our intestines as they digest parts of food which we cannot.

但其實，氣體主要是由我們腸子中的細菌在無法消化一些食物時所製造的。

Our intestine is home to trillions of bacteria living in a symbiotic relationship with us.

腸子內存在大量共生細菌。

We provide them with a safe place to stay and food to eat.

我們提供這些細菌一個安全的空間與可供攝取的食物。

In exchange, they help us extract energy from our food,

作為交換，他們幫助我們吸收食物中的能量。

make vitamins for us, like vitamin B and K, boost our immune system,

為我們製造維他命，像是維他命B和維他命K，促進我們的免疫系統。

and play an important role in gastrointestinal barrier function, motility and the development of various organ systems.

並在我們的胃腸道屏障功能損、能動性與各種器官系統發展中扮演重要角色。

Clearly, it's in our best interest to keep these bacteria happy.

清楚的是，讓這些細菌快樂地生存是我們最大的利益。

Gut bacteria get their nutrition primarily from undigested food,

腸道細菌主要是從未被吸收的食物中獲得營養，

such as carbohydrates and proteins, which come to the large intestines.

像是來到大腸的碳水化合物與蛋白質。

They ferment this undigested food to produce a wide range of compounds,

他們將這些未被吸收的食物發酵，製造出廣泛的自然混合物，

such as short-chain fatty acids and, of course, gases.

像是短鏈的脂肪酸和氣體。

Hydrogen and carbon dioxide are the most common gaseous products of bacterial fermentation, and are odorless.

氫氣與二氧化碳是細菌進行發酵最用中最常產出的無嗅氣體。

Some people also produce methane due to specific microbes present in their gut,

有些人也會因腸子中特殊的微生物而產生甲烷氣體，

but methane is actually odorless, too.

但甲烷實際上也是無嗅氣體。

Well then, what stinks?

如果是這樣，那為什麼會有臭味呢？

The foul smell is usually due to volatile sulfur compounds,

臭味主要是由於揮發性硫化物，

such as hydrogen sulfide and methanethiol, or methyl mercaptan.

像硫化氫和甲硫醇。

These gases, however, constitute less than 1 % of volume,

然而，這些氣體占不到1%的體積，

and are often seen with ingestion of amino acids containing sulfur,

且時常在攝取含硫物質的胺基酸中出現，

which may explain the foul smell of gas from certain high protein diets.

這可以解釋為什麼臭味常來自於攝取高蛋白質食物。

Increased passage of gas is commonly noticed after eating foods with high amounts of indigestible carbohydrates,

攝取許多不易消化的碳水化合物常會導致排放更多氣體，

like beans, lentils, dairy products, onions, garlic, leeks, radishes,

像是蠶豆、小扁豆 、乳製品、洋蔥、大蒜、韭菜、小蘿蔔、

potatoes, oats, wheat, cauliflower, broccoli, cabbage, and brussel sprouts.

馬鈴薯、麥片粥、小麥、花椰菜、椰菜、甘藍、小洋白菜。

Humans lack the enzymes,

人類缺乏酶，

so the bacteria able to ferment complex carbohydrates take over,

因此，能使複雜的碳水化合物發酵的細菌便會運作，

and this naturally leads to more gas than usual.

自然地，這會導致更多氣體的產生。

But if you feel uncomfortable, bloated or visibly distended,

但如果你覺得不舒服、感到腫脹、或明顯浮腫

this mean indicate impaired movement of gas along the gastrointestinal track.

這表示腸胃正進行著氣體受損運動。

It's important not to just blame certain foods for gas and bloating and then avoid them.

重要的是，不應該某些食物會導致放屁與脹氣而避免攝取。

You don't want to starve the bacteria that digest these complex carbohydrates,

你不會希望餓死這些幫忙消化複雜碳水化合物的細菌。

or they'll have to start eating the sugars in the mucus lining of your intestines.

否則，這些細菌恐將開攝取腸子內層黏液中的糖分。

Your personal gas will vary based on what you eat, and what bacteria are in your gut.

你的排氣會因飲食的不同與腸內細菌的不同而有變化。

For example, from the same starting sugar,

舉例來說，雖然皆食用相同糖類，

the bacteria clostridium produces carbon dioxide, butyrate and hydrogen,

梭狀芽胞桿菌會產生二氧化碳、丁酸酯、氫氣，

while propionibacterium can produce carbon dioxide, propionate and acetate.

而丙酸桿菌則會製造二氧化碳、丙酸鹽、醋酸鹽。

At the same time, methanogens can use hydrogen and carbon dioxide produced by other bacteria to generate methane,

同時，甲烷桿菌可以利用其他細菌製造的氫氣與二氧化碳產生甲烷，

which can reduce the total volume of gas by using up hydrogen and carbon dioxide.

甲烷可以透過消耗氫氣與二氧化碳來降低氣體體積。

So there's a complex web among intestinal bacteria

因此，腸內細間形成了複雜的網絡，

allowing them to flourish by either directly consuming undigested food, or using what other bacteria produce.

讓細菌們得以因直接攝取未消化的食物或利用其他細菌的製造物而活躍。

This interaction largely determines the amount and type of gas produced,

細菌間的互動大大地影響了氣體的量與型態，

so gas production is a sign that your gut bacteria are at work.

因此，排放氣體象徵著腸內細菌正起著作用。

But in some instances, people may develop abnormal increased flatulence.

但在一些例子中，人們可能有不正常的脹氣現象。

A common example is lactose intolerance.

一個常見的例子是乳糖不耐症。

Most individuals have the enzyme for breaking down lactose, a sugar present in milk and milk-derived products.

大部分的人們擁有酶，得以分解存在於牛奶或乳製產品中的乳糖，

But some people either lack it entirely, or have a reduced amount,

但有些人不是完全缺乏，就是減少攝取量，

such as after a gastrointestinal infection,

像是經歷腸胃道感染後，

so they're unable to digest lactose products and may experience cramping,

因此他們無法消化乳糖製產品，且可能經歷痙攣，

along with increased flatulence due to bacterial fermentation.

且會因為細菌的發酵作用而增加排氣量。

But remember, most gas is produced as a natural result of bacterial in the intestine,

但請記得，大部分的氣體是由於腸內細菌而產生的自然現象，

and indicates healthy functioning of the gut.

並顯示腸內正健康地運作著。

The amount and type can based on your diet and the bacteria in your intestine.

排氣的量與型態會依據你的飲食與腸內細菌。

Exercise social courtesy while passing gas, and do try to forgive your bacteria.

練習在排氣時保持禮貌，並請原諒腸內的細菌們。

They're only trying to be helpful.

他們只是試圖想成為有益的細菌。