Irritable bowel syndrome or ‘IBS’ is a functional gastrointestinal (gut) disorder that affects the colon, commonly known as the large bowel or large intestine. IBS is thought to affect approximately 10-20% of the population (in developed countries) and is twice as common in women than men.
A ‘functional gut disorder’ refers to a condition where the function of the gut is disturbed even though on investigation no physical or structural abnormalities can be found.
Causes and symptoms
The cause of IBS is not yet fully understood.
Some experts feel it is related to a combination of factors linked to a faulty communication between the brain and the gut, abnormal activity of the muscles (influencing gut motility and how fast or slow our food moves) and a visceral hypersensitivty (influencing pain).
Other possible causes which have been suggested include - family history, low levels of gut inflammation, changes in gut flora particularly after infection or bacterial overgrowth.
Typical symptoms of IBS include: abdominal pain, cramping or bloating (that is relieved or partially relieved by passing a bowel movement), excess wind or flatulence, constipation and/or diarrhoea.
Symptoms of lethargy, nausea, backache and bladder symptoms are less common but can also be features associated with IBS.
It is thought that only 25-50% of people actually seek medical advice for their symptoms but there are interventions that can help!
People with a diagnosis of IBS may have days where they have no symptoms or very mild symptoms however they may also have days when their symptoms are much worse - this is known as a ‘flare up’.
People with IBS may find that these ‘flare ups’ are triggered by one or more factors including:
- stress or anxiety
- after eating certain foods
- when taking certain medications
- at the time of hormonal change
‘Dietary triggers’ are common – up to 9 out of 10 people with IBS report that food ‘triggers’ their symptoms.
IBS should only be diagnosed by a health professional using a symptom based criteria. Formal diagnosis also helps to sub-categorise the type of IBS that someone has based on the dominant symptom i.e. IBS - D (diarrhoea predominant), IBS - C (constipation predominant), IBS - M (mixed).
It is not uncommon for people with gut symptoms to ‘self–diagnose’ IBS however it is important to see your GP or medical professional if you are experiencing symptoms, so that they can rule out any other possible cause (e.g. coeliac disease).
It is also worth noting that IBS should not be confused with the term ‘IBD’ which stands for Inflammatory Bowel Disease. These conditions are very different in both presentation, diagnosis and treatment.
Treatments for IBS
There is no cure for IBS, however there are several treatments (dietary, pharmacological, psychological, etc) available to help manage this condition. The choice of treatment depends on the sub-type of IBS and what is thought to influence or ‘trigger’ the symptoms. This is something that you should discuss with your GP or gastroenterologist (gut specialist).
Over recent years the dietary treatment for IBS has developed. Like most other areas of nutrition or medicine, this change has been in line with new and emerging research.
One area of particular interest has been that of the low FODMAP diet. In the 1980-90’s researchers became interested in the role of poorly absorbed short chain carbohydrates (particularly lactose, fructose and sorbitol) in influencing IBS symptoms. With time and research, they also realised that other groups of carbohydrates – mainly fructans and GOS were also causing problems because of their chain length. The group name for these carbohydrates is now known by the acronym FODMAPs.
- Oligo-saccharide (found in fructans and GOS)
- Di-saccharide (found in lactose)
- Mono- saccharide (found fructose) and
- Polyols (found in sugar alcohols e.g. sorbitol)
The first trial confirming the role of FODMAPs in managing gastrointestinal symptoms was not published until 2006 by a team of Australian researchers at the Monash University in Australia. Since this publication, research has also taken place in the UK at Kings College London, where subsequent studies and trials have taken place showing similar results.
The low FODMAP diet is now considered one of the most effective and evidence-based dietary therapies for the management of IBS.