Gas (Intestinal Gas)

Gases like nitrogen, oxygen, hydrogen, carbon dioxide, and methane travel through the digestive system. Swallowing air while eating or digesting the food the large intestine (colon) is breaking down can introduce these gas into the body. Intestinal gas is standard but can cause discomfort.

This article will discuss the symptoms of gas, what causes gas, how much gas is too much, and what to do to reduce intestinal gas.

Symptoms of Gas

Everyone experiences gas, and symptoms can vary by person. Some of the more common experiences with gas include:

• Belching (burping)
• Flatulence ("passing gas" rectally)
• Abdominal pain from collected gas
• Abdominal bloating, which can be a sign of an intestinal motility disorder (and affects your intestines' ability to move or contract properly)

Causes of Gas

Intestinal gas has two main causes:

• Swallowing air
• Foods and digestion

Some medical conditions can also cause gas.

Swallowing Air

Some amount of air swallowing (aerophagia) is normal and inevitable, but some things can cause you to swallow an excessive amount, leading to belching or flatulence.

Excess air swallowing can happen with the following:

• Eating or drinking too quickly or not chewing well
• Chewing gum
• Smoking
• Loose dentures
• Postnasal drip
• Sucking on items such as pen tops or hard candy
• Drinking hot or carbonated ("fizzy") beverages
• Anxiety

Foods and Digestion

Gases are produced when good bacteria in the large intestine break down some foods that were not digested and absorbed in the small intestine.

Some foods are more likely to cause gas than others.

Foods that contain a high amount of unabsorbable carbohydrates (nutrients found in sugars, starches, and fibers) can cause gas, such as:

• Broccoli
• Cabbage
• Artichokes
• Cauliflower
• Brussels sprouts
• Onions
• Beans
• Pulses
• Lentils
• Prunes
• Raisins
• Apples

Soluble fiber (fiber that becomes liquid in water) can cause gas and is found in foods such as:

• Oat bran
• Beans
• Peas
• Most fruit

Starches can cause gas and are found in foods like:

• Corn
• Potatoes
• Pasta
• Wheat

Some sugars and sweeteners can cause gas and are found in foods, including:

• Fructose
• Lactose
• Sorbitol
• Raffinose

Medical Conditions

Gas is not a medical condition, but some health conditions can produce excess gas. These include:

• Lactose intolerance (the inability to digest lactose in milk products)
• Irritable bowel syndrome (a digestive condition that can cause symptoms such as constipation, cramps, bloating, and diarrhea)
• Inflammation in the intestines (such as inflammatory bowel disease)
• Malabsorption (the inability to properly absorb nutrients)
• Maldigestion (the inability to properly digest nutrients)
• Stomach disorders, such as gastroesophageal reflux disease (GERD), heartburn, or peptic ulcer disease
• Constipation
• Celiac disease (intolerance to gluten)
• Gastroenteritis (infection in the stomach/bowel)
• Overgrowth of normal bacteria in the small intestine

How to Treat Gas

If gas is a symptom of an underlying condition, treating the condition is important. If it is not part of a bigger problem, it only needs treating if it's bothering you.

To determine a treatment plan, your healthcare provider will consider factors such as:

• Age
• Overall health
• Lifestyle habits such as diet and exercise
• Medications you're taking
• Goals for symptom reduction

Some ways to help reduce excessive gas include:

• Avoid foods that increase gas (make sure you are still eating a nutritious, balanced diet)
• Choose carbohydrates that are less likely to cause gas, including rice, bananas, grapes, citrus fruits, lettuce, and yogurt
• Keep a food diary to see if certain foods increase your gas symptoms
• Eat and drink slowly, chewing your food well
• Eat smaller, more frequent meals instead of three large ones
• Get regular exercise, including going for a short walk after eating
• Avoid smoking, chewing gum, and eating hard candy

If lifestyle changes don't help, you may consider medications or dietary supplements with the help of your healthcare provider. These may include:

• Peppermint tea
• Small amounts of ginger (pregnant people should consult with their healthcare provider before taking ginger or ginger products)
• Charcoal tablets (may cause problems with other medications, such as causing them to be less effective)
• Alpha-galactosidase (a dietary supplement found in products like Beano)
• Probiotics from supplements or some yogurts
• Simethicone products
• Bismuth subsalicylate (reduces the noxious odor of some intestinal gases)
• Antibiotics (if there is an overgrowth of bacteria)

The efficacy of these medications and supplements has been debated, but some research suggests they may help. Talk to your healthcare provider about whether they may be worth trying.

Are There Tests to Diagnose the Cause of Gas?

Your healthcare provider may want to investigate if there is an underlying condition that is causing your gas symptoms. They may start with a physical exam that includes the following:

• Looking for distention (swelling or enlargement of the abdomen)
• Using a stethoscope to listen to sounds in the abdomen
• Tapping on the abdomen (to check for tenderness or pain or to listen for a drum-like sound called tympany, which can signal the presence of gas in the digestive tract)
• (Possibly) performing a digital rectal exam

If necessary, your healthcare provider may use diagnostic tools such as:

• Abdominal computed tomography (CT scan)
• Abdominal ultrasound
• Barium enema X-ray (an X-ray with barium sulfate inserted into the colon as a contrast material)
• Barium swallow X-ray (an X-ray that involves swallowing a drink that contains barium)
• Blood work such as complete blood count (CBC) or blood differential (measures the amount of each type of white blood cell)
• Sigmoidoscopy (examines the last part of the large intestine using a flexible, lighted tube)
• Upper endoscopy (a flexible tube with a light and camera is inserted down the throat)
• Breath test (involves blowing into balloon-like bags to check for stomach problems such as bacterial overgrowth)
• Testing for celiac disease
  

When to See a Healthcare Provider 

Gas usually doesn't require medical attention, but see your healthcare provider if you are experiencing symptoms that may indicate your gas is part of a more severe condition, including:

• Stomach/abdominal pain (especially if persistent)
• Rectal pain
• Heartburn
• Nausea and/or vomiting
• Unexplained weight loss
• Diarrhea
  
• Constipation
• Oily or foul-smelling stools
  
• Black, tarry stool
• Blood in the stool
• An increase or change in symptoms
• Treatments that worked before no longer work
• Signs of infection such as fever, chills, vomiting, and joint and/or muscle pain
• Bowel incontinence
  

Summary

Intestinal gas is normal and experienced by everyone. It is caused by swallowing air and the breakdown of food in the large intestine. Gas is released from the body through belching and passing gas rectally.

Gas itself is not dangerous, but see your healthcare provider if other symptoms are present, including persistent pain, changes in stool, or signs of infection.