Why do I have gas?

Intestinal gas results from swallowed air (a condition known as "aerophagia"), from the inadequate digestion of a carbohydrate or complex sugar, or from small bowel bacterial overgrowth (the small bowel should be sterile; bacteria in the small bowel interfere with digestion in many ways). The most common complex sugar to be associated with this problem is Lactose (milk sugar); some people also have a problem digesting Trehalose, a sugar found in all species of mushrooms. Some children also have problems digesting Maltose, Isomaltose, or Fructose. The sugar which is not absorbed then passes from the small intestine to the colon where it is fermented by the colonic bacteria, creating Hydrogen, Methane, or Carbon Dioxide, resulting in cramps or flatulence. Swallowed air differs from the fermentation gaseous products because it has the same composition as room air. We have a noninvasive test (Breath Hydrogen gas chromatography) to determine whether you are Lactose intolerant or whether you have small bowel bacterial overgrowth; we are the only practice in a 60 mile radius with the equipment and the expertise to do this test.