When it comes to conditions that cause misery without being fatal, Irritable Bowel Syndrome (IBS) is near the top of the list. Despite many theories, its causes have largely remained a mystery, impeding treatment, but one team of researchers think they have an explanation, and while they don't yet have medications, let alone a possible cure, their work tells them where to look.
Professor Stuart Brierley of Australia's Flinders University has studied the gut's nerves in search of those that cause the unexplained abdominal pain that is IBS's key feature. "We found receptors which bring about an itchy feeling on skin also do the same in the gut, so these patients are essentially suffering from a 'gut itch',” Brierley said in a statement.
The excruciating pain people with extreme cases of IBS describe may not feel much like itching, but the root cause is the same. In JCI Insight Brierley reports IBS sufferers have more itch receptors, leading to over-activation of their intestinal neurons. The pain gets serious when the itch receptors interact with what is known as the “wasabi receptor” because it triggers our response to the horseradish product popular in Japanese and Korean foods.
Brierley told IFLScience it “could very well be” that this association indicates wasabi consumption could exacerbate IBS, but this was not something the team had tested.
IBS symptoms are not limited to pain, often including constipation or diarrhea. Brierley acknowledged this diversity may be an indication there are multiple causes, but thinks his team's findings apply to “a large subset” of those with the condition.
The finding that the nerves that are overly activated in IBS are also present in the skin may explain why IBS and fibromyalgia often occur together.
Considering IBS affects approximately 11 percent of the population, many of whom would pay a fortune for even partial relief from their symptoms, one might expect investigations of the topic to be quite advanced. However, the economics of medical research rarely work that way.
Pharmaceutical companies seldom fund the basic science that takes decades to lead to useful products. Government funding bodies and philanthropic trusts understandably focus on conditions that kill a lot of people, rather than those that just make some wish they were dead. Combine all that with widespread reluctance to discuss IBS symptoms in polite company and this is one very under-researched condition.
The findings mean molecules that block the itch receptors could provide relief from the pain of IBS and, Brierley thinks, possibly some other symptoms as well. Brierley and co-authors have not yet identified suitable candidates, but think the work they have done brings a treatment close enough that companies will want to sponsor further work.