But methane is actually odorless, too.
但是甲烷也是无味的。
Well then, what stinks?
那么，什么东西这么臭？
The foul smell is usually due to volatile sulfur compounds, such as hydrogen sulfide and methanethiol, or methyl mercaptan.
臭味一般是因为有挥发性的硫化物，如硫化氢和甲硫醇，或巯基甲烷。
These gases, however, constitute less than 1% of volume, and are often seen with ingestion of amino acids containing sulfur,
但是，这些气体只占总量的1%，并且经常因为我们摄入含硫氨基酸，
which may explain the foul smell of gas from certain high protein diets.
这可能解释了臭气是从某种高蛋白饮食中来的。
Increased passage of gas is commonly noticed after eating foods with high amounts of indigestible carbohydrates,
常常在吃了含有大量不易消化的碳水化合物的食物后，会产生更多的气体，
like beans, lentils, dairy products, onions, garlic, leeks, radishes, potatoes,
如豆类，扁豆，乳制品，洋葱，大蒜，韭葱，萝卜，马铃薯，
oats, wheat, cauliflower, broccoli, cabbage, and brussel sprouts.
燕麦，小麦，菜花，西兰花，白菜及甘蓝。
Humans lack the enzymes, so the bacteria able to ferment complex carbohydrates take over,
人体缺乏酶，因此那些能发酵复合碳水化合物的细菌就派上用场了，
and this naturally leads to more gas than usual.
这就会产生比平常更多的气体。
But if you feel uncomfortable, bloated or visibly distended,
但是，如果你觉得不舒服，浮肿或明显肿胀，
this may indicate impaired movement of gas along the gastrointestinal track.
这可能表明沿着胃肠道运动的气体遇到了障碍。
It's important not to just blame certain foods for gas and bloating and then avoid them.
我们不能因为涨肚就归咎于某些食物然后就不吃它们。
You don't want to starve the bacteria that digest these complex carbohydrates,
你不会想饿着这些消化复杂碳水化合物的细菌，
or they'll have to start eating the sugars in the mucus lining of your intestines.
否则它们就会开始消化肠道粘膜里的糖。
Your personal gas will vary based on what you eat, and what bacteria are in your gut.
你身体里产生的气体取决于你吃了什么以及你肠胃里的细菌种类。
For example, from the same starting sugar, the bacteria clostridium produces carbon dioxide,
例如，同样是糖，梭状芽孢杆菌会产生二氧化碳，丁酸盐和氢气，
butyrate and hydrogen, while propionibacterium can produce carbon dioxide, propionate and acetate.
然而丙酸杆菌可以产生二氧化碳，丙酸和乙酸。
