Flatulence: Gas buildup in the intestines

Gas in the small intestine or colon is typically caused by the digestion or fermentation of undigested food by bacteria found in the bowel. Gas can also form when your digestive system doesn't completely break down certain components in foods, such as gluten, found in most grains, or the sugar in dairy products and fruit.

Other sources of intestinal gas may include:

• Food residue in your colon
• A change in the bacteria in the small intestine
• Poor absorption of carbohydrates, which can upset the balance of helpful bacteria in your digestive system
• Constipation, since the longer food waste remains in your colon, the more time it has to ferment
• A digestive disorder, such as lactose or fructose intolerance or celiac disease

To prevent excess gas, it may help to:

• Eliminate certain foods. Common gas-causing offenders include beans, peas, lentils, cabbage, onions, broccoli, cauliflower, whole-grain foods, mushrooms, certain fruits, and beer and other carbonated drinks. Try removing one food at a time to see if your gas improves.
• Read labels. If dairy products seem to be a problem, you may have some degree of lactose intolerance. Pay attention to what you eat and try low-lactose or lactose-free varieties. Certain indigestible carbohydrates found in sugar-free foods (sorbitol, mannitol and xylitol) also may result in increased gas.
• Eat fewer fatty foods. Fat slows digestion, giving food more time to ferment.
• Temporarily cut back on high-fiber foods. Fiber has many benefits, but many high-fiber foods are also great gas producers. After a break, slowly add fiber back to your diet.

• Try an over-the-counter remedy. Some products such as Lactaid or Dairy Ease can help digest lactose. Products containing simethicone (Gas-X, Mylanta Gas, others) haven't been proved to be helpful, but many people feel that these products work.

  Products such as Beano, particularly the liquid form, may decrease the gas produced during the breakdown of certain types of beans.