Windy symptoms explained 

Complaints about having too much wind or gas are very common. This leaflet provides a brief explanation of how windy symptoms are produced and where bowel gas comes from.

We hope that this pamphlet is helpful to you in understanding and dealing with your windy problems. If you are otherwise healthy, windy symptoms are not due to disease. But if they are severe or troublesome or if you are worried about them you should seek the help of your doctor.

The Gut

The gut is a muscular tube stretching from the gullet (oesophagus) to the back passage (rectum) and is about 40 feet long when stretched out. It usually contains about 200ml of gas and every day we pass 400–2000ml of this gas out through the back passage as wind (or flatus, as it is technically known).

What is the gas?

Over 90% of flatus is made up of 5 gases – nitrogen, oxygen, carbon dioxide, hydrogen and methane: the remaining 10% contains small amounts of other gases.

Where does it come from?

The nitrogen and oxygen come from air which is swallowed; the carbon dioxide is produced by stomach acid mixing with bicarbonate in bile and pancreatic juices. These gases get into the small intestine where most of the oxygen and carbon dioxide are absorbed into the blood stream; the nitrogen is passed down the large bowel (colon).

The small intestine is the place where the food we eat is digested and absorbed; the residues, such as dietary fibre and some carbohydrates, pass on to the large bowel. The colon contains different kinds of bacteria which are essential to good health and which ferment material from the small intestine, producing large volumes of hydrogen, methane, carbon dioxide and other gases. Most of these gases are absorbed into the blood stream and eventually excreted in the breath: the rest is passed as flatus.

Going from the top to the bottom of the gut, the principal windy complaints are:

Belching or burping (air eructation)

Every time we swallow we take some air into the stomach. A belch is an involuntary expulsion of wind (gas) by the stomach when it becomes distended from an excess of swallowed air. Eating rapidly or gulping food and drink, drinking a lot of liquid with meals, chewing gum, smoking or wearing loose dentures promote air swallowing. Some people swallow saliva to relieve heartburn and swallow air at the same time. Other people swallow air without noticing it, especially when they are tense. Fizzy drinks including beer cause belching because they release gas (carbon dioxide) into the stomach.

Chronic or repetitive burping (aerophagy)

In this case air is not swallowed into the stomach but sucked into the gullet and rapidly expelled. Repetitive belching like this can last for minutes at a time and is very embarrassing. There is no medical treatment and the cure lies in realising the cause. Air cannot be sucked in when the jaws are separated, so repetitive belching can be temporarily controlled by firmly clenching something like a pencil between the teeth. Some people develop aerophagy because of discomfort in the chest. If you develop belching associated with chest discomfort – especially discomfort associated with exertion – or if you have difficulties in swallowing – you should seek medical advice.

Bloating

Abdominal bloating is a common complaint that is often blamed on excess gas in the bowel. In people with irritable bowel syndrome, in which the gut is more sensitive to distension, that is not the case and the normal amount of gas causes discomfort. Because the muscular contractions of the gut are not co-ordinated, its contents do not pass along in an orderly fashion and this causes additional discomfort. Research has shown that when small amounts of gas are passed into the intestine, people with irritable bowel syndrome experience bloating and pain, whereas other people tolerate the same or even larger amounts of gas without any discomfort. Bloating may also be caused by rich, fatty meals which delay stomach emptying.

Bloating is often associated with abdominal distension so that clothing has to be loosened. This is usually due to relaxation of the abdominal muscles in an unconscious attempt to relieve discomfort. The distension usually disappears on lying flat or on contracting the abdominal muscles.

Bloating is difficult to treat. A high fibre diet can cause bloating in some people, but in  others may relieve bloating, because fibre absorbs water in the gut and gently distends it, helping to prevent the uncoordinated contractions that are partly responsible for bloating. Irritable bowel syndrome may be made worse by stress or anxiety so that stress may also be responsible for your bloating. Some people find that activated charcoal or defoaming agents (containing simethicone) are helpful. Avoiding gassy drinks may help. If the bloating is severe your doctor may prescribe drugs that help to coordinate the contractions of the gut or prevent spasms.

Bloating due to a build up of gas also occurs in some intestinal diseases such as Crohn’s disease or bowel tumour. These conditions cause other symptoms such as weight loss, abdominal pain or diarrhoea and require prompt medical investigation.

Rumblings/grumblings or noisy guts (borborygmi)

Bowel noises or borborygmi are produced when the liquid and gas contents of the intestine are shuffled backwards and forwards by vigorous movements of the gut. They may be produced by hunger, or by anxiety, or a fright: they are very common in irritable bowel syndrome.

Loud borborygmi or rumblings result from contractions of the intestines caused by diseases like Crohn’s disease or bowel obstruction. These conditions are associated with other symptoms such as severe abdominal pain and should be reported to your doctor.