The exact cause of IBS is unknown, but most experts think that it is related to increased sensitivity of the gut and problems digesting food.  For some people IBS can start after an infection of their gut.

Your body usually moves food through your digestive system by squeezing and relaxing the muscles of the intestines in a rhythmic way.  However, in IBS it's thought that this process is altered, resulting in food moving through your digestive system either too quickly or too slowly.  If food moves through your digestive system too quickly it causes diarrhoea, because your digestive system does not have enough time to absorb water from the food.  If food moves through your digestive system too slowly it causes constipation, as too much water is absorbed, making your stools hard and difficult to pass.

Psychological factors such as stress can commonly cause IBS symptoms.  However, this does not mean that IBS is "all in the mind", because symptoms are very real.  Unpleasant emotional states such as stress and anxiety can trigger chemical changes that affect the normal workings of the digestive system.

This does not just happen in people with IBS.  Many people who have never had IBS before can have a sudden change in their bowels when faced with a stressful situation, such as an important exam or interview.

Managing IBS

There is no cure for IBS. However with modifying dietary and lifestyle factors we aim to control or limit the symptoms of IBS.

Tips to improve symptoms of IBS  

• Eat regular meals
• Adjust the amount of fibre in your diet-this vary for an individual depending if they suffer more from diarrhoea or constipation
• Maintain a good fluid intake.
• Limit the amount of caffeine in your diet. It is also advised to limit fizzy drinks and alcohol.
• Regular exercise often improves symptoms
• Avoid artificial sweeteners such as sorbitol

Sometimes more specialist diets may be recommended to treat the symptoms of IBS. Commonly a FODMAP diet is advised. FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These are resistant types of carbohydrate that are not easily broken down in the gut. For IBS suffers, these can cause pain, bloating and wind. As this diet can restrict a lot of foods e.g. some fruits and vegetables, animal milk, wheat products and beans, if is important that it is done with the correct supervision so that nutritional deficiencies do not occur.

Some medications may be prescribed to treat the symptoms.  Medication such as buscopan and mebeverine help to relax the gut walls and are often used to treat cramping. 

Anti-diarrhoea medications may help those people who suffer for IBS related diarrhoea. Loperamide is commonly used. This works by slowing the movement of food through the gut.

Laxatives are used in those people who suffer from constipation. A bulk forming laxative is usually whats recommended. Always start at a low dose, and increase slowly until your symptoms are under control. Ensure you are drinking plenty of water with these types of medications.

For some people psychological therapies can be helpful. These therapies can teach you techniques to help you control your condition better. Cognitive behavioral therapy is often used and there is good evidence to show that this can be beneficial for some people.