Frequent gas is usually caused by swallowed air or foods that ferment in the gut, like beans, dairy, or carbonated drinks.
Normal
Passing gas 14 to 23 times a day is normal, according to the NIDDK.
Causes
- Swallowed air (fast eating, chewing gum, carbonated drinks).
- Fermentation of fiber and carbs by gut bacteria.
- Foods: beans, onions, broccoli, dairy, artificial sweeteners (sorbitol).
- Lactose or fructose intolerance.
- Constipation.
- IBS and celiac disease.
What helps
Eat slowly, limit trigger foods, add fiber gradually and walk after meals.
Over-the-counter
Simethicone, activated charcoal, lactase and Beano.
See a doctor if
Gas comes with pain, weight loss, blood in stool or changes in bowel habits.
Normal gas
Passing gas is normal. The average person passes gas 13 to 21 times a day, according to studies on gastrointestinal gas. The gas is mainly nitrogen, oxygen, carbon dioxide, hydrogen and methane, with a small share of sulfur compounds causing smell. Flatus volume ranges from about 0.5 to 1.5 liters per day.
Where gas comes from
- Swallowed air, from eating fast, drinking through straws, chewing gum, smoking or talking while eating.
- Fermentation in the colon, where bacteria break down carbohydrates that the small intestine did not digest.
- Carbonated drinks, which release carbon dioxide.
Common causes of more gas
- Foods high in fermentable carbohydrates: beans, lentils, onions, garlic, cabbage, broccoli, wheat, apples and prunes.
- Sugar alcohols such as sorbitol, mannitol and xylitol in sugar free gum and candy.
- Lactose intolerance, affecting about 65% of the world’s adults to some degree.
- Fructose intolerance and fructans.
- A sudden rise in fiber intake. Increase fiber gradually and drink water.
- Irritable bowel syndrome, celiac disease, small intestinal bacterial overgrowth, constipation and gastroparesis.
- Medicines such as acarbose, metformin and some antibiotics.
What helps
- Eat slowly and avoid gulping.
- Keep a food diary and cut out likely triggers for two weeks.
- Try a low FODMAP diet under a dietitian’s guidance if IBS is suspected.
- Walk after meals, since movement helps gas move through.
- Limit carbonated drinks and chewing gum.
- Peppermint oil capsules may help with IBS symptoms in some studies.
Over-the-counter options
- Simethicone breaks up gas bubbles, though evidence of benefit is weak.
- Alpha-galactosidase (Beano) helps digest the sugars in beans and vegetables if taken before meals.
- Lactase enzyme tablets for lactose intolerance.
- Activated charcoal has limited proof.
See a doctor if
Gas comes with severe pain, blood in stool, unexplained weight loss, vomiting, persistent diarrhea or constipation, or a swollen abdomen. These can point to conditions that need testing.
Gas composition and intake
Intestinal gas is about 59 percent nitrogen, 21 percent hydrogen, 9 percent carbon dioxide, 7 percent methane and 4 percent oxygen, with sulfur gases making the smell. Most people pass gas 13 to 21 times a day, according to the NIDDK. Foods rich in raffinose, fructans, lactose and sorbitol increase gas. Swallowed air is increased by fast eating, gum, smoking and carbonated drinks. A gradual increase in fiber, walking after meals, peppermint oil capsules and simethicone may help. Persistent gas with diarrhea, weight loss or blood in stool needs evaluation for celiac disease, lactose intolerance or inflammatory bowel disease.
Based on data from the NIDDK and the American College of Gastroenterology
