Gas and bloating

Gas is made in the stomach and intestines as your body breaks down food. Different people tolerate foods differently. With increased gas in the bowel lumen, many people feek generalised abdominal distension and some suffer with abdominal pain. Usually this gas-related distension settles overnight only to build up again the following day.
All people pass gas but some people pass more than others. It is normal to pass gas even 20 times per day.
Intestinal gas is made up of a number of different gases, including nitrogen, hydrogen, carbon dioxide, hydrogen sulfide, ammonia and methane. The foul smell is generally caused by small traces of the last three gases listed. Gas that forms after eating meat and eggs tends to smell bad, while gas derived from fruits and vegetables does not usually have an odour.


Common causes

• Swallowed air can occur when eating quickly or after consuming gas-containing liquids like soft drinks or beer. Try and eat more slowly and avoid carbonated drinks.
• Some people absorb nutrients like lactose, fructose and fructans poorly. Bacteria in the gut metabolise these nutrients and produce gas, which is passed as flatus. Foods that are major gas producers for some people may cause little gas for others. Try a low FODMAP diet.
• Constipation can cause bloating and distension and bacteria have more time to produce gas from any nutrients sitting in the bowel. Try and avoid constipation.
• Some medicines and nutritional supplements can cause bloating and gas as side effects. Review your therapies with your doctor and if necessary, try alternatives.
• Antibiotics may disrupt the usual balance of gut bacteria, resulting in more gas-producing bacteria. Probiotics may help to rebalance the bacteria population.
• Many women have bloating around the time of their periods because they retain fluid and may experience constipation at this time. Don’t be surprised if bloating is worse around the time your period begins.
• Stress alters bowel motility and may worsen gut hypersensitivity. Stress management may improve your abdominal symptoms as well as your enjoyment of life.
• Rarely, bloating can be the sign of serious disease such as coeliac disease (gluten allergy), ascites (fluid in the abdomen), tumours (especially ovarian cancer), pancreatic insufficiency or bowel obstruction. Discuss your symptoms with your doctor to see if further investigations are appropriate.

Low FODMAP diet
High FODMAP diet