Why do I have gas?

Billions of bacteria live deep inside the colon and feed on our undigested food. "In fact, you have more bacteria in your gut than cells in your own body. They do something that's really very important. They actually make things like vitamin K and folic acid, key nutrients you have to have. They actually digest some of the foods that we can't otherwise digest," says Dr. Mehmet Oz,Vice-Chair and Professor of Surgery at Columbia University.

The side effect of this digestion, however, is gas. "There's no way of getting around it. And so for most of us out there, you realize that a little gas is probably good for you," Dr. Oz says. By the way, men and women in every major study have the exact same amount of flatulence. don't feel bad, guys."

Everyone has gas. Burping and "passing gas" is normal. Since it is embarrassing, many people believe that they pass gas too often or have too much gas. A person actually having too much gas is rare.

Most of the time, gas in the body is odorless. The odor of passed gas comes from sulfur made by bacteria in the large intestine. Sometimes, gas causes bloating and pain. Not everyone has these symptoms. How much gas the body makes and how sensitive a person is to gas in the large intestine affect how uncomfortable one feels.

This answer is based on source information from the National Institute of Diabetes and Digestive and Kidney Diseases.