Gas Moves in Funny Ways

Gum for Gas?

Medical Author: Jay W. Marks, MD
Medical Editor: Dennis Lee, MD

We all produce gas in our intestines, especially our colons, or, at least, our intestinal bacteria produce it, from undigested food. We are fortunate because the overwhelming majority of the gas that is formed by the bacteria is used up by other bacteria in the intestine.

Some people are more fortunate than others. All of the gas produced in their intestines is used up by bacteria, and they pass gas (fart) very little, that is, unless they eat foods that bacteria can use to form lots of gas-like beans-that overwhelm even the most ardent, gas-devouring bacteria. A small amount of intestinal gas is absorbed into the blood from the intestine and is eliminated in the breath. The gas that is not used up by bacteria or eliminated in the breath must be passed. Passing gas relies on the functioning of the intestinal muscles. The gas distends the intestine, and the intestinal muscles respond by contracting and pushing the gas further along the intestine until the gas is finally expelled. Sometimes this process fails.

I underwent removal of a portion of my sigmoid colon for diverticulitis. The surgery was done laparoscopically and went very well. There were no complications, and my discomfort was easily controlled with medication. Manipulation of the intestines during surgery "stuns" the intestinal muscles, and they usually stop working for a time. Before patients can eat after surgery, their intestinal muscles must start working. The signs that the muscles are working is the presence of abdominal gurgling (borborygmi) and the passing of gas. Laparoscopic surgery stuns the intestine less than "open" (large incisional) surgery, and the intestinal muscles usually recover quickly.

I was particularly pleased since after surgery my abdomen never stopped making noise. It was even making noise in the surgical recovery room. Forty-eight hours after the surgery, I was feeling very well, and I began passing gas. (Quoting my surgeon, it was "music to his ears.") As a reward for my, actually my intestine's, good behavior, I was given a breakfast of clear liquids. Within an hour of finishing the meal, I stopped passing gas, my stomach began making less noise, and my abdomen became distended with gas. My intestinal muscles had stopped working.

I was disappointed. My surgeon was reassuring, however, saying that my intestines just weren't ready. "Tomorrow they'll be working, and we'll try again."

That night I began passing gas again, much more than the previous day. My abdomen became flat and I actually became hungry. Surely my intestines were ready now. In came the clear liquid breakfast again, and I relished it. Within an hour I stopped passing gas, my stomach began making less noise, and my abdomen became distended. What was going on?

Needless to say I was now very disappointed. My intestines were keeping me from going home. As I lay in the hospital bed I remembered reading an article-in Time magazine, no less-in recent weeks, about a study that looked at the effect of chewing gum on the return of intestinal muscle function following laparoscopic surgery. The study found that chewing gum led to a substantially quicker return of intestinal function.

At the time I remembered this, a friend was visiting me in the hospital. I asked her to go to the hospital's gift shop and buy me a few packs of chewing gum, which she gladly did. I began chewing.......and chewing.......and chewing. Within twenty minutes I started passing gas like crazy, and it never stopped. (Fortunately, my visitor had already left.) I had a great lunch and went home the following morning.

The control of our stomachs and intestines is complex, and, to some extent, the stomach and intestines control their own activity. Thus, when the intestine becomes stretched with gas, the intestinal muscles react by contracting and expelling the gas. Food causes the stomach and intestinal muscles to reduce their contractions. As a result, food-as well as the gas that is produced by bacteria-travels more slowly through the intestines, and this allows more time for the food to be digested and absorbed into the body. My clear liquid breakfast may have been having such an effect, but instead of just slowing my intestine down, the food was stopping my intestine from working at all.

Intestinal function is influenced by nerves coming from the brain and spinal cord, especially the vagus nerve. The vagus nerve, for example, is responsible for making our stomachs growl and our mouths water when we are hungry and smell something delicious. In this case, the brain is telling our intestines via the vagus nerve to "get ready." (The growling is really a manifestation of contracting stomach and intestinal muscles.) It is likely that my chewing gum stimulated the vagus nerve which, in turn, overcame the effect of the food that I had eaten.

The study on chewing gum had appeared in a recent surgical journal. As an internist and gastroenterologist but not a surgeon, I would not have seen it. Fortunately, the lay press had picked up on the study. I subscribe regularly to several internal medicine and gastroenterology journals, but I think I also am going to keep up my subscription to Time magazine.


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References Indigestion.