Cause of Irritable Bowel Syndrome.

The cause of Irritable Bowel Syndrome is still unknown. Some experts think IBS is a Motility Disorder.  A hyperactive or oversensitive gut is another possible cause of IBS. and the gut will react to changes influenced by food, hormones and stress.

With the typical chaotic bowel habit of IBS, it is not surprising that it is thought of as a motility disorder. The transit time from ingestion of food to excretion is abnormal.

Sometimes it is slower than normal causing constipation and other times it is faster causing diarrhoea. There are two types of IBS, constipation predominant and diarrhoea predominant. Some have diarrhoea and constipation alternating. Stools in IBS can vary from watery and unformed to hard pellets.

Some say there is a link between diet and IBS.
Certain foods will trigger IBS symptoms. Intestinal gut activity is stimulated by ingesting food. This is the Gastro-Colic reflex and develops in response to food entering the stomach. Gastro-Colic reflex in IBS is strongest after fatty or large meals. This strong gut contraction can cause abdominal pains and or diarrhoea.

There is no evidence that food causes IBS but certain foods and the volume consumed at one time can trigger symptoms.

One suggestion is that it is a brain-gut disorder. The Enteric Nervous System is a complex interconnection of brain cells in the gut. Some researchers believe that to understand IBS, we have to understand the workings of the Enteric Nervous System.

The highest level of serotonin, a neuro-chemical is found in the gut. Significant research is currently done on the chemical and its role in IBS.

Serotonin affects the nerves in the intestine and controls contractions of the smooth muscles of the gut. Low levels of serotonin lead to constipation and higher than normal levels cause diarrhoea.

Psychological factors such as anxiety, stress and depression can affect the gut. In addition psychological trauma such as physical, emotional and sexual abuse can affect the gut. In IBS, records show a higher incidence of such trauma. Addressing these issues may produce better long term results.

Gastroenteritis as a cause of IBS: IBS can develop is 20-30% of cases of severe gastro-enteritis. The common infective organisms are Campylobacter jejuni, Salmonella shigella, and Escherichia coli. Serotonin levels in gastro-enteritis is very high and in cases that develop IBS this high level continues.

In women with IBS, the hormones progesterone and estrogen vary during the menstrual cycle and the symptoms may fluctuate. The passage of food residue along the large gut is affected by the female hormones.

Yeast according to Prof. Jonathan Bostoff of The Meddlesex Hospital could be a possible cause of IBS. These patients have reduced levels of friendly bacteria, Lactobacilli and Bifidobacteria in their large bowel. This results in overgrowth of Candida.