Flatulence, or passing gas, is a normal daily phenomenon.
胀气，或者放屁，是正常的日常现象。
Most individuals, yes, that includes you,
大多数人，是的，这包括你，
will make anywhere from 500-1500 milliliters of gas and can pass gas ten to twenty times a day.
每天将会产生500-1500毫升的气体并且每天会放十次到二十次的屁。
But where does this bodily gas come from?
但是身体里的气体从哪里产生的呢？
A small proportion may come from ingesting air during sleep, or at other times,
小部分的气体可能来自于在睡眠或其他时间吞入的空气，
but the majority of gas is produced by bacteria in our intestines as they digest parts of food which we cannot.
但是大部分的气体，是由我们肠道里的细菌产生的，因为他们可以消化部分我们无法消化的食物。
Our intestine is home to trillions of bacteria living in a symbiotic relationship with us.
我们的肠道里住着上亿万的细菌,它们和我们是共生的关系。
We provide them with a safe place to stay and food to eat.
我们为他们提供了安全的居住环境和吃的东西。
In exchange, they help us extract energy from our food, make vitamins for us, like vitamin B and K, boost our immune system,
作为交换，他们帮助我们从食物中提取能量，为我们制造维他命，例如维生素B和维生素K，增强我们的免疫系统，
and play an important role in gastrointestinal barrier function, motility and the development of various organ systems.
并在肠屏障功能，胃肠运动及各器官系统的发展中发挥重要作用。
Clearly, it's in our best interest to keep these bacteria happy.
如此可见，我们最好让这些细菌快乐的生活下去。
Gut bacteria get their nutrition primarily from undigested food,
肠道细菌主要从未消化的食物里取得营养，
such as carbohydrates and proteins, which come to the large intestine.
像到大肠里的碳水化合物和蛋白质，
They ferment this undigested food to produce a wide range of compounds, such as short-chain fatty acids and, of course, gases.
他们将未消化的食物发酵从而产生一系列的化合物，例如：短链脂肪酸，当然，还有气体。
Hydrogen and carbon dioxide are the most common gaseous products of bacterial fermentation, and are odorless.
氢和二氧化碳是最常见的细菌发酵的气体产物，并且他们是无味的。
Some people also produce methane due to specific microbes present in their gut.
由于有些人肠胃里有某种特定的微生物，他们还会产生甲烷。
