Irritable Bowel Syndrome is a chronic condition but in spite of extensive research, our understanding of the causative elements are still embryonic. The symptoms are different in individual sufferers and in individual sufferers the symptoms can vary from time to time. This makes it difficult to pin point one specific cause.
As symptoms in some Irritable Bowel Syndrome patients worsen after meals, it is suggested that IBS is a dietary problem. This, however, is a natural phenomenon. Food intake stimulates increase intestinal activity. This is the gastro-colic reflex. In Irritable Bowel Syndrome, this effect is exacerbated and symptoms develop. There is no clear evidence that food reaction is a cause of IBS but certain foods can aggravate symptoms. Lactose intolerance and gluten allergy (Coeliac Disease) are considered separate from IBS.
Some experts suggest that Irritable Bowel Syndrome is a motility disorder. In IBS the transit time of passage of food through the gut is altered. If it is too slow, more water is absorbed from the faecal residue resulting in constipation. If it is too fast, not enough water is absorbed and diarrhoea results. The chaotic behavior of the gut in IBS results in variable transit time and can cause constipation and / or diarrhoea. There is no clear evidence that Irritable Bowel Syndrome is simply a motility disorder.
As much as 25% of people with Irritable Bowel Syndrome admit that their IBS developed after a certain bout of gastroenteritis. This is more often bacterial. During gastroenteritis, serotonin level in the blood is elevated. High level of this hormone causes diarrhoea. In individuals that go on to develop Irritable Bowel Syndrome, the serotonin level remains high. This results in diarrhoea-predominant IBS.
This raises the possibility that IBS is an inflammatory condition. However, biopsies from the large gut of Irritable Bowel Syndrome patients have not shown inflammation.
The inflammatory module triggered the idea that in IBS the large gut is colonized by bad bacteria. Since Helicobacter pylori was implicated in stomach problems and good bacteria had conferred benefits in other gut conditions, probiotics were used to treat IBS. The results vary. There are two main types of good bacteria in the gut. Lactobacilli and Bifidobacteria.There are very good trial results for some and poor results for others. Bifidobacterium infantis 35624 has shown benefits in women with Irritable Bowel Syndrome. It helped both diarrhoea and constipation. Trials, however, have been hampered by low numbers, variable criteria and different species of good bacteria. The Mayo Clinic reviewed trial results and concluded that probiotics for IBS are largely ineffective.
Some experts think that Candida is a cause of IBS. If this was this case antifungal treatment would help. A subgroup of gastroenterologists thinks IBS is a hypersensitivity disorder. It is recognized that symptoms of Irritable Bowel Syndrome can be triggered by stress, drugs and food. Certain food will trigger significant worsening of symptoms. It is still unclear whether hypersensitivity of the gut is a cause of IBS.
The more plausible cause of Irritable Bowel Syndrome is a faulty Brain-Gut connection. The Gut has its own nervous system called the Enteric Nervous System and is connected to the brain via the Vagus nerve. The body-mind aspect of IBS is becoming very popular with experts. Stress can cause diarrhoea and depression can result in constipation.
The Brain-Gut connection was demonstrated recently. With the use of Functional Magnetic Resonance Imaging and Positron Emission tomography, experts are able to show gut activity directly related to brain function.
The Brain-Gut connection explains why treatment such as psychotherapy, cognitive behavioral therapy, biofeedback and hypnotherapy are so effective. Gastroenterologists are baffled by the great improvement derived from hypnotherapy. Some case of refractory (nothing works) IBS, following a course of hypnotherapy are symptom free and remain so at the five year follow up. Listen in on a hypnotherapy session and you will hear the hypnotherapist saying positive things about IBS and giving the patient belief that control is within reach. Some create the picture of the large gut as a river flowing smoothly along. Is the hypnotist just adjusting the Brain-Gut axis is a patient with Irritable Bowel Syndrome?