Ask the doc: When should I be concerned with the amount of gas 
I am experiencing?

—Vince L., graduate student, University of Alaska—Anchorage*

People experience gas in several different ways: as eructation (burping), as intestinal gas and bloating, and as flatulence (farting). All these are perfectly normal body processes, but having excess gas can be embarrassing, uncomfortable, and/or concerning. The causes, as we’ll discuss below, are usually treatable with some diet and behavioral modifications.

To answer your question directly, I default to the Intrusiveness Rule: If gas, or anything else, is intruding on your academic life, work life, social life, sleep pattern, etc., especially after trying usual self-care measures, it’s a good idea to consult a medical provider at your student health center or primary care provider’s office.

What causes excess gas?

There are three common causes of excess gas:

  1. Swallowing air via talking while eating, drinking through a straw, smoking, etc.
  2. Over-producing gas, especially common when eating foods with high levels of indigestible fiber (cellulose)
  3. Inadequate absorption of intestinal gas

Technically, there is also a fourth cause, which is expansion of existing intestinal gas due to changes in altitude, but this doesn’t usually apply outside of scuba diving and mountaineering (though, I guess you are in Alaska, so I shouldn’t rule out mountaineering).

Burping, bloating, and flatulence…oh my!

Let’s look more deeply into each of the three usual patterns of extra gas.

Eructation (burping)

Burping is a release of gas from the esophagus or stomach. It is usually connected with air swallowing. Ordinarily, food and liquids go to the digestive system (down the esophagus to the stomach) and air goes to the respiratory system (down the trachea to the lungs), but these systems share a common entry point, the nasopharynx (the upper part of the throat that connects the nose and mouth). Air swallowing is trapping or propelling air into the digestive system rather than the respiratory system. When this air is released, it comes up as a burp.

Some people have a habit of taking in too much air when eating, usually because of gulping food or talking while eating. Others may be sensitive to carbonated beverages, or take extra air into the stomach via chewing gum or inhaling (as with smoking/vaping/juuling/etc.).

Sometimes anxiety contributes, too, by affecting breathing patterns. Patients with excessive burping may be releasing gas trapped in the esophagus, rather than the stomach, pointing to a behavioral, as opposed to physiological, cause of the burping. Most of these causes can be effectively managed with appropriate treatment, which often includes behavioral therapy.


Bloating is the sense of uncomfortable fullness or swelling in the abdomen, sometimes with a sensation of needing to release gas for relief. There are various possible causes, but often digestive disorders are to blame. Lactose intolerance, celiac disease, or, perhaps, a change in the relative proportions of different gut bacteria types can cause incomplete digestion of certain foods. These undigested components get consumed by gut bacteria that produce more gas as byproducts than during normal digestion. Persistent bloating, especially if intrusive, usually warrants evaluation by a medical provider.

Excessive flatulence

Excessive flatulence may be due to overproduction of gas, a problem often associated with diet. Some foods have a higher proportion of indigestible parts. Sweet corn is a good example. The inside of a kernel of corn is composed of a simple starch and is readily digested. The husk (the shell and base of the kernel), however, is made of cellulose, which humans can’t digest. The residual indigestible components reach the low intestine, where they are metabolized by gut bacteria that produce various gases as byproducts.

High-fiber foods, which have many benefits, are especially likely to cause trouble, even more so when in raw form. The cruciferous vegetables (e.g., broccoli, Brussels sprouts, cabbage), as well as usual suspects such as beans, are common causes of excess gas. Other common food triggers are onions, milk products, and dried fruits.

In other cases, the complaint isn’t so much about the flatus (gas) itself as a concern about odor. The odor of flatus is usually attributable to sulfur-containing compounds and other aromatic molecules derived from certain foods. Sometimes, consultation with a registered dietician is recommended to help minimize undesirable effects from foods without unnecessarily restricting dietary choices.

*Name changed