The feeling of being bloated is another nasty symptom commonly associated with Irritable Bowel Syndrome (IBS). This most normally occurs in the lower, large intestine. Bloating is a result of trapped gas (usually because excess has been produced) distending the wall of the intestine which triggers pain receptors. This results in an expanding waist line and unfortunately, often, flatulence to go with it.
The exact cause for bloating in IBS is not always clear. However there are some possible explanations.
If food arrives in the large intestine having been poorly digested, for example because of a food intolerance, naturally occurring bacteria in the large intestine begins a process called fermentation, which produces gas. Fermentation naturally occurs in the bowels as our diet contains certain indigestible elements known as dietary fibre. However, if food appears at the large intestine that should have been digested beforehand (suggesting some dysfunction higher up in the digestive tract) excess gas may be produced as a result. The bowel is likely to become irritated with the presence of excessive undigested food and populations of bacteria feasting on it. ]
Leading on from this, research has suggested that people suffering from IBS may actually have different populations of bacteria residing in their gut. The intestines, in particular the large intestine, contain thousands of different strains of bacteria which vary from person to person. It is possible that ‘bad’ strains give rise to undesirable symptoms, a lot of which are associated with IBS, such as bloating and flatulence.
For severe or recurrent bloating please refer to your doctor as there may be a more serious reason for distension of the abdomen.
Kassinen, A. et al (2007) The fecal microbiota of irritable bowel syndrome patients differs significantly from that of healthy subjects. Gastroenterology 133(1):24-33