Science

Scientists discover why people with IBS feel pain after eating

There are thought to be millions of people in the UK with irritable bowel syndrome (IBS), yet despite this little is known about the condition. According to the NHS, IBS is usually a lifelong problem and has no known cure, though changes in diet and some medicines have been found to alleviate symptoms.

Now, researchers at KU Leuven in Belgium have uncovered a mechanism behind the stomach pain and discomfort felt by IBS sufferers that could lead to potential new treatments using antihistimines.

The team’s previous research demonstrated that the production of histamine – the same compound that is produced by the body’s immune system in response to an allergen, such as pollen – was linked with abdominal pain in those with IBS.

But unlike an allergic reaction, in which the immune response can be triggered throughout the entire body, they found that with IBS the production of histamine was localised within the intestine.

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“At one end of the spectrum, the immune response to a food antigen is very local, as in IBS,” said KU Leuven gastroenterologist Prof Guy Boeckxstaens. “At the other end of the spectrum is food allergy, comprising a generalised condition of severe mast cell activation, with an impact on breathing, blood pressure, and so on.”

As there is a link between gastrointestinal (GI) infection and the onset of IBS symptoms, Boeckxstaens and his team hypothesised the immune system to become sensitive to particular foods eaten during infection – sensitivity that lasted even after a patient had recovered.

To test this, they first gave half a group of mice a GI infection and then fed them all with a protein called ovalbumin, which is known to elicit an immune response in sensitive individuals.

Then, a few weeks after the infected mice had recovered, the team once again presented the whole group with the protein. The mice that were previously infected with the bug again released histamines in their intestines while those not infected had no response. The scientists also noticed the activation of certain cells which produce the histamine, called mast cells.

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The team then repeated the experiment using by injecting gluten, wheat, soy and cow milk into the intestines of a small group of 12 human patients with IBS and saw the same localised immune reactions as they did with the mice.

The researchers have now begun a larger clinical trial to investigate the effect of treating sufferers of IBS using antihistimines.

“This is further proof that the mechanism we have unravelled has clinical relevance. But knowing the mechanism that leads to mast cell activation is crucial, and will lead to novel therapies for these patients,” said Prof Boeckxstaens. “Mast cells release many more compounds and mediators than just histamine, so if you can block the activation of these cells, I believe you will have a much more efficient therapy.”

Why does coffee make me need a poo?

You’re not alone. In surveys, 30 to 60 per cent of people report that they need a poo after drinking a coffee. Like any food or drink, coffee stimulates the ‘gastrocolic reflex’, where the colon contracts in response to stretching of the stomach or digestive activity in the small intestine, which gives the sensation of needing a poo.

In a 1998 study at the University of Iowa, researchers found that caffeinated coffee causes more colon contractions than decaffeinated coffee or hot water. However, decaffeinated coffee still had more of an effect than water, so caffeine can’t be entirely to blame. Other chemicals in coffee that could be stimulating the colon include chlorogenic acid and the snappily named N-alkanoyl-5-hydroxytryptamide.

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