Flatus

The complaint of excessive flatus is made when a person believes he/she passes wind more often than their friends or more often than in the past. Often this is because an embarrassing incident like a loud or smelly break of wind in public has led to the belief that something is wrong.

A normal individual passes wind through the rectum an average of 15 times per day (ranging between 3 and 40 times), depending on diet. A high fibre diet produces more wind than a low fibre diet or a low carbohydrate diet. So if you think you have excessive flatus, count every time you break wind – even the little silent ones – for a day or so. If you break wind fewer than 40 times a day then you are normal.

But whatever your count you may wish to reduce it. Most flatus is generated by the normal bacterial fermentation of food residues in the colon. On the principle ‘no bugs – no gas’ you might think that antibiotics would work. But they don’t. Although the bacteria are killed off by the antibiotics, they quickly re-establish themselves. Besides, antibiotics produce more flatus in most people.

A high fibre diet has mixed blessings. It produces a satisfying stool, protects against colon cancer, may protect against stroke and heart disease, may help people to lose weight and improves symptoms in irritable bowel syndrome. The downside is that a high fibre diet produces a lot of flatus. However, it is possible to reduce flatus production even on a high fibre diet by avoiding the big gas producers. Beans are notorious gas producers – “beans are good for the heart: the more you eat the more you break wind”. They contain certain carbohydrates called oligosaccharides which cannot be digested in the small intestine but are like food to bacteria in the colon. Cabbage, brussel sprouts, cauliflower, turnips, onions, garlic, leeks and some seeds such as fennel, sunflower and poppy all produce a lot of gas in the colon. Reducing the amount of these foods in the diet will reduce flatus. Sometimes activated charcoal seems to reduce the amount (and smell) of flatus.

Some otherwise healthy people lack the enzyme necessary to digest lactose, the sugar in cow’s milk. As a result the lactose is fermented by the colon bacteria with the production of large amounts of carbon dioxide and hydrogen. The condition is called lactose intolerance and besides gas production may cause abdominal cramps. It occurs most commonly in people born in the Mediterranean area, but can occur anywhere. The ‘cure’ is to reduce milk intake to a level at which symptoms are controlled. Your doctor may carry out special tests to confirm the diagnosis. CORE produces a separate factsheet on lactose intolerance , available on our website.

Sorbitol, a sweetener used in diabetic diets and present in jams, sweets and sugarless chewing gum, is also not digested in the small intestine and can give rise to flatus for the same reason as lactose.

Certain medical conditions such as Crohn’s disease, coeliac disease and other disorders which interfere with small bowel absorption of nutrients cause excess flatus because of impaired digestion. These conditions are usually associated with symptoms such as abdominal pains, weight loss, anaemia and/or persistent diarrhoea with pale, smelly stools that tend to float in the toilet pan. These symptoms require medical investigation. CORE produces separate leaflets on both Crohn’s disease ,Coeliac disease and irritable bowel syndrome.

Loud wind 

Loud wind is produced by powerful contractions of the bowel wall forcing gas out through a narrow anus – the muscle at the bottom of the rectum that keeps the intestinal contents in their place. There is not much you can do about this except grin and bear it, but measures to reduce flatus production may help. 

Smelly wind

This is not your fault! It is caused by smelly substances like indoles, skatoles and hydrogen sulphide that are produced by bacterial fermentation in the colon. Garlic and onions, many spices and some herbs of the fennel family, particularly asafoetida which are used in Indian cooking, produce smelly gases. Beer, white wine and fruit juices give rise to smelly hydrogen sulphide in some people. Worse still, some of these smelly gases are absorbed into the blood stream and excreted in the breath as well, so that you may smell at both ends: be warned. Eating a lot of fatty food can cause smelly wind, and it is worth cutting down on fat if this is a problem.