No one will give you a specific cause of Irritable Bowel Syndrome. IBS is a motility disorder some experts say. A hyperactive or oversensitive gut is another possible cause of IBS. and the gut will react to changes influenced by stress, food and hormones.
With the typical chaotic bowel habit of IBS, it is not surprising that it is thought of as a motility disorder. There is an abnormality in the transit time of ingested food.
In diarrhoea the transit time is faster and in constipation it is slower. IBS is generally divided into two groups, diarrhoea predominant and constipation predominant. In some cases constipation and diarrhoea alternate. Stools in IBS can vary from watery and unformed to hard pellets.
Some say there is a link between diet and IBS.
IBS symptoms can be triggered by certain foods. Intestinal gut activity is stimulated by ingesting food. This is a normal action and the most common is the Gastro colic reflex. This reflex is strongest after breakfast. In IBS, large meals, fatty meals or just the wrong meal can trigger a very strong gastro colic reflex. 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 gut has a complex network of brain cells called the Enteric Nervous System. This “Brain of the Gut” is connected to the Brain. Some researchers believe that to understand IBS, we have to understand the workings of the Enteric Nervous System.
The Gut has the richest supply of serotonin in the body. This chemical is closely connected to the nervous system. 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. Trauma suc h as physical, sexual and emotional abuse can affect the gut. Statistics show that there is a greater incidence of psychological trauma and disturbances in IBS. 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. Escherichia coli, Salmonella shigella and Camplobacter jejuni are the most common organisms involved. 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.
Prof. Jonathan Brostoff of Middlesex Hospital believes that yeast is involved in some cases of IBS. These patients have reduced levels of friendly bacteria, Lactobacilli and Bifidobacteria in their large bowel. This results in overgrowth of Candida.