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Irritable Bowel Syndrome (IBS) and Fodmaps

Irritable Bowel Syndrome (IBS)

IBS is dysfunction of the large intestine (colon) characterised by cramping, abdominal pain, bloating, constipation, and/or diarrhoea. Though not a serious, life-threatening condition, it can have a very negative impact on a sufferer’s life. Past generations called it a “sensitive gut” and noticed that, for an individual, some foods were implicated more than others.

IBS involves how the muscles of the intestinal wall, and their nerve supply work. At colonoscopy, (direct vision of the colon), the muscles can be seen to be “twitchy” rather than having a smooth coordinated “peristaltic” action. Most people can control their symptoms with diet modification, stress management, and medications. IBS is twice as common among women as men, but this could partly be because women are more open about health problems. It usually, but not always, begins around age 20. Many people let IBS persist for several years before seeing a doctor.

The cause of IBS is not known but contributing factors can include:

  • Stress (e.g. anxiety may result in diarrhoea before an exam)

  • Imbalance of gut flora (bacterial population) of the gut may result in increased gas production

  • Specific food intolerances with malabsorption of some chemicals upsetting the normal colonic function (see Fodmaps below)

  • Undiagnosed mild coeliac disease (an autoimmune disease in which people cannot digest gluten, a substance found in wheat, rye, and barley)

  • Hormonal changes, which seem to influence the activity of the bowels; women's symptoms are often worsen around menstruation time


The symptoms that define IBS vary from person to person but include abdominal pain that is relieved by a bowel movement; diarrhoea or constipation - sometimes both; a sense of urgency to pass stool; incomplete passage of stool; mucus in the stool; and gas or bloating.

The symptoms are usually intermittent, occurring from a few times a week to once a month. IBS also might go away for years and suddenly return. Bleeding, fever, weight loss, and persistent severe pain are NOT symptoms of IBS. If you have these symptoms you should see your General Practitioner (GP) to exclude a more serious condition such as bowel cancer or inflammatory bowel disease.



In the last decade research by nutritionists and gastroenterologists has identified a group of sugars in the foods we eat that are poorly absorbed in the small intestine. These chemicals produce gas (after fermentation by bacteria),as well as attracting water into the gut when they reach the large bowel. In some people these chemicals may cause or worsen IBS symptoms and should be avoided in large amounts. FODMAPS is an acronym and a limited example of each is given.

Fermentable Oligosaccharides (Fructanse.gonions and galacto-oligosaccharides e.g. chick peas), Disaccharides (Lactose e.g. milk products and soft cheeses), Monosaccharides (excess Fructose e.g. apples, figs, pears)And Polyols (Sorbitol, Mannitole.g. in chewing gum). A person may only have a problem with a specific member of the Fodmaps group.

How We Care

There is no cure for IBS, but symptoms can be relieved. Different medications can be used such as anti-anxiety drugs, antispasmodic drugs to reduce cramping, and drugs for either constipation or diarrhoea.Our doctors will assess your symptoms carefully and only undertake investigations (such as specialist referral for colonoscopy) if there are concerning features. 

Once the diagnosis of IBS has been made our doctors will work with you to reduce its impact on yourlife. Dietary changes may help relieve symptoms. By keeping a list of the foods that seem to increase symptoms, you can learn what foods to avoid or minimize. It may be as simple as too much of one particular item. 

Tests can be done to exclude coeliac disease (gluten intolerance) and breath testing can be arranged to identify fructose, lactose or sorbitol absorption problems. These kinds of tests are not always required. A dietitian may take you through a low Fodmaps diet so that it is individualized for you by determining which of the carbohydrates you need to avoid.

IBS is a specific, often disabling, gut condition. Improvements have been taking place in its management. If you have been “suffering in silence” please make an appointment with one of our doctors.

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