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This video explains the causes of flatulence (farting) and why certain foods give you gas.

What causes wind?
Wind is produced by the digestive system as enzymes and bacteria break down carbohydrates and proteins in your food.

After food has been broken down and mixed up in the stomach, it is digested and absorbed in the small intestine. Anything that is left over, such as dietary fibre and some carbohydrates, pass into the large bowel.

Any change in your usual diet can cause your body to produce more wind than usual. This is because the bacteria that live in our bowels get used to coping with whatever we eat on a regular basis, and have a bit more difficulty handling anything we're not used to.

If you regularly overeat then your stomach will have to work faster than normal, breaking down all the extra food, which can lead to more wind.

Foods such as beans, cauliflower and cabbage contain insoluble fibre and take a long time to break down in the bowel, which can also trigger excess wind.

Certain foods, such as kidney beans and artichokes cause an overproduction of bacteria in the stomach, which can in turn lead to excessive flatulence. Food containing a lot of fibre such as baked beans and brown rice, and drinks such as beer and coffee can also contribute to flatulence.

Other foods that can cause flatulence in some people are lettuce, apples, turnip, lentils, parsnip, swede, onions, brussels sprouts, beans, garlic, leeks and products made with malt extracts.

Foods that are rich in sulphur such as cauliflower, eggs and meat are more likely to make the gas smelly. Bacterial fermentation in the colon can also cause smelly wind.

Medical conditions that can cause flatulence are:

  • Irritable bowel syndrome (IBS).
  • Gastroenteritis.
  • Diverticulosis or diverticulitis.
  • Coeliac disease.
  • If your thyroid is not working properly.
  • If your body is not absorbing food properly.
  • If part of your intestine is blocked.

Flatulence can also be an unwanted side effect of laxatives taken for constipation, antibiotics, certain medications, or from misuse of opiate -based medicines such as pethidine and morphine.

Above all, the most common cause for flatulence is swallowing air. This is because each time we swallow we take air into the stomach. Eating too fast, gulping food and drink, drinking with meals, chewing gum, smoking, or wearing loose dentures can all contribute to swallowing excess air. The air normally leaves the body as a belch (burp) but sometimes it can travel further into the intestines and can only be released through your anus.

  • show glossary terms
The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.

The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.

Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

The anus is the opening at the end of the digestive system where solid waste leaves the body.

Last reviewed: 05/05/2006

Next review due: 05/11/2007

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