What your wind says about you: 6 fascinating facts about flatulence

Flatulence can be a sign that all is not well with your digestive system. We explain where wind comes from – and what it might mean for your health.

What exactly can your wind say about your health? And what else do we need to know about flatulence?

1. It’s about bacteria and fermentation

“Most intestinal gas comes from colonic bacteria breaking down indigestible fibre and starches not absorbed in the small intestine,” explains GP Dr Sarah Brewer.

“They do this through a process of fermentation that releases short chain fatty acids, heat and gases such as hydrogen, carbon dioxide, methane and sometimes foul-smelling sulphur-containing gases such as hydrogen sulphide.

“This excess gas cannot be reabsorbed to any great extent, although some passes into the blood stream and is excreted through the lungs. A small amount is used up in other bacterial metabolic reactions, but around 1 to 2.5 litres per day is expelled through the rectum.

2. It comes from many sources

“In general, wind in the stomach is expelled upwards by burping, while wind in the small intestines and colon is expelled via the anus,” says Dr Brewer.

Bowel gases, he explains, come from several different sources:

  • Gas present in fizzy drinks
  • Air swallowed with food
  • Air swallowed nervously by some people (aerophagia)
  • Gases released during bacterial fermentation of fibre in the large bowel.

3. It is sometimes painful

“Excessive flatulence often accompanies abdominal pain, and bloating. It burbles around causing pain, distension and embarrassing noises (borborygmi) until escaping suddenly and sometimes explosively,” Dr Brewer explains.

It happens a lot. Research suggests that most people pass gas 12-20 times per day and the amount of residual gas remaining in the bowels at any one time is up to 200ml.

4. It can be a sign of IBS

“Wind (flatus) is a common symptom in Irritable Bowel Syndrome,” says Dr Brewer.

“The make-up of flatus gases is no different in people with IBS than in others, but some differences have been noticed. Wind passes through the gut of people with IBS more slowly than in those without symptoms, and sufferers seem to be more sensitive to the distension it causes.

“The gas is also more likely to pass backwards through the bowel and to reflux up into the stomach to be expelled by burping. Wind symptoms therefore seem to be due to abnormal motility of the intestines and disordered passage of wind through the gut, rather than to the production of excess gas.”

5. It can be an indicator of food intolerance

“Some people with excessive wind lack the right enzymes to digest certain foods,” says Dr Brewer, “especially dairy foods which require enzymes such as lactase to break down milk sugar (lactose).

“Inadequate amounts of lactase lead to lactose intolerance, which can produce wind and loose bowels. These people will find their symptoms improve dramatically on cutting out milk based products from their diet.”

6. It can be a sign of cancer

One symptom of bowel cancer is excessive wind and bloating, and if this is accompanied by other symptoms such as blood or mucus in your stools, weight loss, pain and fatigue, see your doctor.

Equally, never farting could possibly be a sign something’s up too: “I’m not sure there’s anything robust about flatus and cancer – except that if you pass NO farts, this could be a sign of intestinal blockage (but you would also have distension and pain).”
If you’re worried, check with your doctor.

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