Besides infections and post-infectious states, there are many different theories on the origin of irritable bowel syndrome. There is still disagreement whether the problem is caused peripherally (the gut itself), centrally (in the brain) or in both.
Bowel Syndrome – Trigger Points
Muscular problems don’t seem like a likely cause for IBS, but myofascial trigger points in the back, abdomen and chest can cause various gastrointestinal symptoms. These symptoms are mediated through the autonomic nervous system and can include diarrhea, constipation, stomach pain, cramps, bloating, gas, nausea, vomiting, acid reflux (GERD) and lowered gut motility, even gastroparesis.
Bowel Syndrome – Endocannabinoid Deficiency
Endogenous cannabinoids or endocannabinoids are important neurotransmitters. Clinical endocannabinoid deficiency (CECD) has been suggested as a potential cause of conditions such as fibromyalgia, migraines and IBS.
Bowel Syndrome – Leaky Gut
Increased gut permeability or “leaky gut” refers to a condition where the permeability of the gut is increased and may let molecules that would not normally pass through to enter the bloodstream. Besides IBS symptoms this may have systemic effects as well.
Bowel Syndrome – Inflammation
Inflammation of the gut may be involved in some causes of IBS, especially post-infectious IBS. People with IBS are often found to have increased numbers of mast cells and other inflammatory cells in their intestine. Discussion of actual autoimmunity as a cause is, however, rare.
Stress has been suggested as a possible cause of this inflammation, but genes may also play a part. A preliminary study suggested that polymorphisms in certain genes controlling for secretion of proinflammatory cytokines (that is, genetic suspectibility to higher levels of inflammation) may place the individual at a higher risk of IBS.
Bowel Syndrome – Allergies and Intolerances
Celiac disease is a well-known cause of gastrointestinal symptoms. Milder forms of gluten intolerance have also been suggested to play a part in IBS and some people find relief in a gluten-free diet. Intolerances to dairy and salicylates (an aspirin-like compound found in many fruits and veggies) can also cause IBS symptoms.
Most intolerances do not show up in normal allergy tests and it may be difficult to figure out whether something is an intolerance or whether it is just a food that happens to worsen IBS symptoms. Either way, the solution is simple: cut out the offending food.
Central sensitization refers to a condition in which damage or inflammation in peripheral tissue cause changes in certain parts of the spinal cord, making it hypersensitive to pain, even when the original damage is no longer present.. Central sensitization has been suggested as a possible cause for fibromyalgia and IBS, which often occur together.