Gastrointestinal Gas

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What causes intestinal gas?

Everyone has gas in their stomach and intestine. Air gets there mainly by being swallowed. The air that is swallowed and not removed by belching will pass through the digestive tract and eventually pass as gas from the rectum. Additional gas in the colon (large intestine) is created when bacteria digest certain components of food that are not completely absorbed.

The most common sources of gas are:

  • Fiber-rich foods such as whole grains and bran
  • Sugars found in mushrooms, and some fruits and vegetables
  • Lactose, in people with lactose intolerance
  • Sweeteners like sorbitol, xylitol, and high fructose corn syrup used in food, candy and chewing gum
  • Carbonated drinks like soda, which release a large amount of carbon dioxide gas

The most common gases produced in the intestine are hydrogen, carbon dioxide, and methane, which are odorless. The offensive smell of gas is released as tiny amounts of proteins, fat, and carbohydrates get broken down by certain bacteria.

What are the symptoms of intestinal gas?

Everyone passes gas each day. This is normal and does not have to be painful or considered a problem. Excess gas that can be caused by eating large amounts of indigestible foods can cause bloating, cramps, pain, and diarrhea. Excessive belching or burping can result from frequent air swallowing and is seen in children who suck on pacifiers or cry for long periods of time. In older children, chewing gum can be a factor. Purposeful air gulping is a common ‘talent’ learned and displayed by some school-age children and teenagers.

How is gastrointestinal gas controlled?

The best way to control intestinal gas is to avoid the consumption of those foods that generate the gas. Trial and error is often needed to pinpoint the main culprit of increased gas in an individual.

  • Avoid fiber rich vegetables and fruits, particularly items such as beans, asparagus, mushrooms, cauliflower, or broccoli, brussels sprouts, cabbage, and bran. Cooking these foods and pre-soaking
    them will diminish their ability to form gas.
  • Avoid milk or milk products if lactose intolerant
  • Avoid sweetners like sorbitol or xylitol
  • Avoid carbonated drinks
  • Avoid chewing gum

Use of a lactase enzyme supplement will help those with lactose intolerance. Use of medications such as simethicone or activated charcoal is popular but often do not help much. Daily exercise can help stimulate passage of gas through the digestive tract.

Edited by: Athos Bousvaros, MD and Priya Raj, MD
January 2020

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North American Society for Pediatric Gastroenterology, Hepatology and Nutrition
The Association of Pediatric Gastroenterology and Nutrition Nurses
North American Society for Pediatric Gastroenterology, Hepatology and Nutrition Foundation
The NASPGHAN Council For Pediatric Nutrition Professionals
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