Causes of Flatulence

We all do it. Cows produce about 100 liters of intestinal gas every day! You? Hopefully a lot less. But what is it that causes flatulence?

What Causes Intestinal Gas?

To start things off, here's a gas-related question from the midterm exam that I give my applied Applied Microbiology students. See if you can get it right:

Question: What organism deserves the most credit for making you fart?

1. the phartotrophic cells of your intestine
2. members of your normal intestinal flora (bacteria)
3. the one that pulled your finger
4. burritos

Well, you can blame it on your bacteria! It is actually certain microbial flora in your intestines that create flatulence. Our intestines are colonized by friendly bacteria that assist us in digesting our food. These microbes help out by eating some of the indigestible carbohydrates (fiber) that we consume. When certain gas-forming bacteria (and bacteria-like microbes called Methanogens) ferment these fiber-filled foods, they create methane as a waste product, and methane is the fuel of flatulence.

Sometimes I Fart a Lot. Why?

Gas-forming bacteria are always eating and always creating waste gas. But the more indigestible molecules that you feed your intestinal bacteria, the more waste products they create, and the more gas you have.

Beans are well-known for giving people gas, and, as would be expected, beans are full of indigestible fiber. Although reducing the amount of indigestible fiber in your diet may reduce the amount of flatulence that you (and those around you) suffer from, eliminating fiber is not a good idea.

Fiber is critical for digestive health. It helps stool move through the intestines, reducing constipation, and actually helps you regulate your weight by slowing the speed at which food molecules are absorbed into the body. The more slowly food molecules are absorbed, the more likely it is that you'll work off those calories before they get stored as fat.

If intestinal gas is painfully uncomfortable, or you feel that the amount of flatulence that you have is far above what would be considered normal, by all means, see a doctor. Your physician may have some simple suggestions for reducing your discomfort.

Why Are Some Farts Especially Stinky?

The variety of scents that farts come in results from the type of food being digested. Some vegetables, such as broccoli and cabbage, for example, contain the chemical element sulfur. Sulfur smells like rotten eggs and contributes to particularly smelly farts.

Sources

Bauman, R.W. (2003). Microbiology. Pearson Benjamin Cummings.