Irritable Bowel Syndrome 

IBS; is it just a sensitive tummy or is it all in the mind?

by Dr Nick Read, MA, MD, FRCP, Chair of the IBS Network.



 What is IBS?    Diagnosis?    What is the Cause of IBS?    Treatment
Is There Support?    IBS Facts & Figures

What is IBS?

Irritable Bowel Syndrome (IBS) is the name given to an otherwise unexplained long-term illness characterised by symptoms of abdominal pain, bloating, and bowel irregularity; diarrhoea or constipation or an alternating pattern that fluctuates between the two. But IBS doesn’t just affect the gut; most patients have unexplained symptoms in other parts of the body as well. Lassitude, fatigue, indigestion, heartburn, backache, urinary symptoms, muscular aches and pains, headaches, nausea and breathlessness are all frequently experienced by patients diagnosed with IBS.  Thus it is not surprising that IBS overlaps with other unexplained illnesses like M.E., Fibromyalgia, functional dyspepsia and irritable bladder. Anxiety and depression are common in all of these conditions, leading some to conclude that all of them are different expressions of a malaise or sensitivity that affects both the mind and the body.  For most people, IBS is a fairly benign condition that tends to recur at times of stress and change, but for some it is profoundly disabling, ruling their lives and confining them to their homes.



The symptoms of IBS are non-specific. Abdominal discomfort and bowel disturbance are the way the gut reacts when it is affected by many other disease processes. Thus symptoms of IBS feature in other more specific diseases, including coeliac disease, which is four times as common in patients diagnosed with IBS, inflammatory bowel disease (IBD: Crohn's disease and ulcerative colitis), bowel cancer, gallstones and thyrotoxicosis.  Health professionals need to be alert to the occurrence of red flag indicators such as rectal bleeding, weight loss, fevers and anaemia, which would indicate damage to the bowel, and should always screen more common and serious diseases that present like IBS, such as Coeliac Disease, Inflammatory Bowel Disease, and bowel cancer. So every new patient with symptoms suggesting IBS should at least have a haematological screen and a blood test for coeliac disease and inflammatory markers (ESR and CRP). The use of faecal calprotectin, recently introduced as a specific marker for bowel inflammation, may prevent unnecessary referral to hospital for colonoscopy.  And any patient above the age of 50, who develops symptoms of bowel irritability for no obvious reason, should be screened for bowel cancer.


What is the Cause of IBS?

There is no agreed cause of IBS, though symptoms are commonly brought on by life changes, and difficult life situations, but they may also be triggered by food.

Physiological studies show enhanced gastrointestinal motility and sensitivity in some patients. This can make them very sensitive to foods, especially fats and coffee, that stimulate contraction, coarse insoluble fibre, which is a direct irritant, and those foods (fruit, vegetables, wheat and milk) that contain unabsorbed sugars that are fermented, releasing gas that distends the bowel.  Increases in bowel sensitivity are more often detected in patients with predominant diarrhoea and often associated with a mild increase in inflammatory cells. It is associated with bowel irritability with notable changes in intestinal motility and transit time. Patients with predominant constipation may have an insensitive gut.

Many of the factors that have been suggested as causes of IBS may actually be consequences. Food intolerance occurs in most patients with IBS, but is rarely specific. Instead, it is most likely the response of a sensitive gut to foods that stimulate contraction or are fermented and cause gaseous distension. Bile acid malabsorption, which occurs in IBS diarrhoea, is most likely a consequence of rapid small bowel transit. And alterations in bacterial flora are probably the result of antibiotics or changes in nutrient delivery caused by alterations in diet and/or small bowel transit. Bacterial overgrowth of the small intestine may be a misinterpretation of the breath tests used to diagnose it.     

This begs the question, ‘what is it that makes the gut more (or less) sensitive and reactive?’ The two most common factors are stress and infection. Stress does not always connote a serious psychological trauma, it may include a change in life circumstances, the rekindling of an upsetting memory or the result of feeling overwhelmed and under pressure. Life may not necessarily be more traumatic for people but it is certainly more busy; there is just too much stuff happening that distracts us and impinges on our equilibrium. Emotional tension acts via the sympathetic nervous system to cause increases in sensitivity. People with IBS are often young women with busy life styles and many responsibilities, who may have struggled to cope with difficult situations, and are particularly concerned about their diet, worried they may have more serious illness and desperate to find a cure. It is always important to ask yourself, ‘What was going on at the time the illness started (or recurred)?’ and ‘What is it about my life situation that causes my IBS to flare up?’ Fluctuations in IBS frequently follow the vicissitudes of life. 

About 10% of people who suffer an attack of gastroenteritis go on to develop persistent symptoms of IBS, even though no sign remains of the original infection. Such patients often have intestinal hypersensitivity and a mild to moderate increase in inflammatory cells in the wall of the gut. Post-infectious IBS is more likely in patients who were anxious or depressed at the time of their gastroenteritis and may have had something else going on in their lives.

IBS can tend to run in families, but there is no specific combination of genes for IBS. The association is more likely to be that families share the same diet, experience the same stress and harbour the same bacteria in the colons.



IBS and other unexplained illnesses can present in so many different ways that it is more important to understand the patient, the way they live, the food they eat, what has happened to them, and the situations that upset them than it is try to make the symptoms fit a disease with a definitive scheme of management. There are no agreed treatments for IBS, though patients find that their unique combination of medicines, diet, psychological support, complementary therapies and lifestyle changes can help. 


Drug treatment can be useful to reduce symptoms: antispasmodics for pain, laxatives for constipation and antimotility agents such as loperamide for diarrhoea. But all too often, management of one symptom can make another worse. For example, treatment of diarrhoea with loperamide can exacerbate pain, while the use of soluble fibre for constipation can make bloating worse. It is so difficult to establish the efficacy of drugs for IBS by randomised controlled trials because the placebo response is so good. 


Food can certainly make symptoms of IBS worse.  The sensitive bowel will react to any food that causes contraction and distension. Culprits include fatty foods and coffee that stimulate the gastrocolonic reflex and cause pain, insoluble fibre and hot spices that irritate the gut directly, and the poorly absorbed carbohydrates in wheat, milk, many fruits and vegetables, which when fermented, inflate the colon with gas. The latter have been characterised by the acronym FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols). Low FODMAP diets can be particularly useful for the management of bloating. There was a time when dietary fibre was advocated for all patients with IBS, but recent guidelines only advise soluble fibre for constipation. Some patients with predominant constipation even respond well to the stimulant effect of FODMAPs without getting bloated. For IBS, it is never the case that one remedy fits all.    


Probiotics and the prebiotic carbohydrates that sustain them are popular treatments for IBS. With the realisation of the far reaching effects of the biomass of bacteria within our colon, what could be more compelling than advice to take the good bugs every day to keep the bad bugs at bay? It chimes with popular fears of pollution, terrorism – at least we can do something about the terrorists inside us! The science would seem to make sense, but do they work?  A recent meta-analysis of all the trials of probiotics in IBS suggests that on balance they have a positive effect, but the data is not overwhelming and many experts conclude that trials of some of the probiotics work for some of the patients some of the time. The latest NICE guidelines suggest that a month’s course of probiotics may be worth a trial and if that doesn’t work, another probiotic could be tried.  

Psychological Treatments

Just as there is no definitive cure for life, there is no specific treatment for IBS. As ever, it is important to understand the patient. The most effective treatments are often those that are directed at the whole person. Psychological therapies, such as counselling, relaxation, hypnotherapy and psychotherapy, can be very effective. Antidepressants may relieve symptoms when more specific symptomatic medication fails. 

Complementary Therapies

Disenchanted with medical options for their IBS, many patients seek help from complementary therapists. Although scientific evidence for most of these methods is weak or non-existent, nonetheless they are popular and the patients testify that they work. The focussed attention of the therapist, the time taken to understand the patient, and the customisation of a meaningful therapy enhances the placebo effect. In IBS, it is not so much that the treatment is effective, it is more that the patient has confidence in it. Complementary therapists are healers. They know how to motivate and inspire confidence.   


The development of effective screening tests for coeliac disease and inflammatory bowel disease will reduce referrals for negative colonoscopy for all but the most serious and complicated cases. This can only increase the work load for the busy GP, particularly as patients with IBS tend to be frequent attenders. There are an estimated 12 million patients with IBS in the UK. Even if we assume that only a third of these will seek medical treatment, the numbers are overwhelming. Thus, patient education and self-care have been widely recommended to deal with the burden of IBS.  

If people can understand their illness and the rationale and options for treatment, they have choices and they can learn to manage their symptoms.

The IBS Network, the UK’s national charity for IBS, has this year published its comprehensive IBS Self Care Plan, which is available online as an information resource for everybody with IBS. With numerous illustrations, exercises, videos and audios, patient letters and links, this deals with the issues people with IBS want to know about: diagnosis, what else might it be, diet, stress, medical management, therapies, as well advice on how to manage the main symptoms, pain, bloating, diarrhoea and constipation and a unique symptom tracker which can be downloaded and taken to the doctor. 

But management of IBS is not just a matter for giving a patient with IBS a leaflet, connecting them to the website and expecting them to get on with it. They are frequently worried and upset, and need advice from somebody with time and an attitude they can trust. This has led some to propose that non-medical health care practitioners, dietitians, counsellors, pharmacists and practice nurses could play a greater role in the day-to-day management of patients with IBS, guiding them into how to use The Self Care Plan and other resources, checking for other symptoms that might indicate life threatening bowel disease, running dedicated IBS clinics or facilitating self-help groups.


Is There Support?

The IBS Network is the national charity for IBS (Registered Charity No. 1057563). It offers advice, information and support to those with IBS, their carers and health professionals, and aims to raise public awareness of IBS and the issues surrounding the condition. It has created an extensive and comprehensive IBS Self Care Plan, dealing with all aspects of the diagnosis and management, free of charge on its website. It also publishes a quarterly journal and a monthly newsletter, runs a telephone helpline and email response service, staffed by health professionals, coordinates an email discussion forum and a network of self-help groups and issues Can’t Wait cards. Membership costs just £24 a year, which includes their quarterly magazine Gut Reaction

IBS Facts & Figures

  • One in seven people in the UK suffer from IBS.
  • IBS is more prevalent than diabetes, epilepsy and asthma combined.
  • IBS affects more women than men.
  • IBS affects people of all ages (even young children) and all social classes.
  • Many have symptoms every day, creating a significant impact on work, relationships and quality of life. 
  • IBS is a long-term unexplained illness defined by the association of abdominal pain, bloating and bowel disturbance. 
  • Other symptoms can include fatigue, lethargy, muscular aches and pains, indigestion, bladder irritability, backache, headache, dizziness, anxiety, depression and many other symptoms. 
  • There is no distinct cause for IBS, though symptoms can be triggered by diet and life events/situations.
  • There is no specific treatment, though medicines, changes in diet, psychological support, and complementary therapies can help.
  • Every patient with IBS is different. Education and self-help supported by health care professionals may be the most effective management. 
  • The IBS Network offers information, guidance, support and advice for all patients with IBS.