Definition of gas (intestinal gas)
Intestinal gas is always present throughout the length of the digestive tract, from the stomach to the rectum. We notice intestinal gas only if it is excessive or causing pain.
Excess intestinal gas in the stomach or upper intestine may result in excess burping or belching. Excess intestinal gas in your lower intestine may result in increased gas being passed from your anus (flatulence). Excess gas from either location can cause cramping or pain, often without an obvious pattern.
Most people burp occasionally and people pass gas rectally several times a day as a normal part of daily activities and food breakdown. Sometimes, excessive intestinal gas can indicate a digestive disorder.
Causes of gas (intestinal gas)
Excess upper intestinal gas may result from swallowing more than a usual amount of air while eating, drinking or chewing gum. Lower intestinal gas is the normal byproduct of bacterial action on food that is not broken down until reaching the colon. Intestinal gas related to bacterial action is made up of hydrogen, carbon dioxide and sometimes methane.
Foods that cause gas
Some foods contain substances that aren’t fully digested until they are acted upon (metabolized) by the bacteria in the lower intestine, where they’re broken down into simpler substances, including gas. Common gas-producing foods and substances include:
- Beans and lentils
- Dairy products containing lactose
- Fructose and sorbitol, which are found in some fruits and are also used as sweeteners
Digestive disorders that cause gas
Excessive intestinal gas — belching or flatulence more than 20 times a day — sometimes indicates a digestive disorder such as:
- Celiac disease
- Dumping syndrome
- Food allergy or intolerance?
- GERD — Gastroesophageal reflux disease
- Irritable bowel syndrome
- Lactose intolerance
- Peptic ulcer
When to see a doctor
By itself, intestinal gas is rarely a sign or symptom of a serious condition. It can cause discomfort and embarrassment, but it’s usually just a sign of a normally functioning digestive system. If you’re bothered by intestinal gas, try changing your diet.
However, see your doctor if your gas is persistent or severe, or if it’s associated with vomiting, diarrhea, constipation, unintentional weight loss, blood in the stool or heartburn.