If you think you have irritable bowel syndrome (IBS), you are not alone. More than 1 in 10 people are likely to have IBS at some time in their life. It is actually the commonest gut problem that people consult their doctor about. It is most likely before the age of 45 years but can begin at any age.

Irritable bowel syndrome

  • Irritable bowel syndrome is a very common condition caused by abnormal contractions of the muscles in the large intestine and increased sensitivity of the bowel to the presence of gas and movement. It appears to be made worse by stress.
  • Symptoms include recurring, cramp-like or colicky abdominal pain and irregular bowel movements, from diarrhoea to constipation.
  • The symptoms are not usually severe and may disappear without treatment for periods ranging from days to years.
  • Irritable bowel syndrome can usually be diagnosed without specialized investigations, but if there is any doubt, the colon may be examined using barium enema or colonoscopy.
  • Modifying your diet can relieve symptoms. There are no specific foods that make irritable bowel syndrome worse in everyone, though diets containing very large quantities of roughage (fibre) may increase susceptibility to abdominal bloating and wind. Usually, patients adjust their diet according to their own experiences, but this is best done under the supervision of someone trained in giving dietary advice.
  • If symptoms persist, your doctor may recommend bulking agents, or else tablets that alter the movement of the bowel, prevent muscle spasm or reduce the bowel’s sensitivity to the presence of gas and to muscle movements.

Picture irritable bowel syndrome

How to Tell If You Have Irritable Bowel Syndrome

Here are some questions to help you decide if you might have IBS.

  1. Have you had pain or discomfort in your abdomen for at least 6 months?
  2. Does the discomfort improve when you open your bowels?
  3. Does your poo look different from previously (loose and watery, or lumpy and hard)?
  4. Do you need to have a poo more or less often than previously (more than 3 times a day)?
  5. Does your abdomen feel bloated?
  6. Are the symptoms worse after eating?
  7. Is there any mucus mixed in with the poo or in the toilet pan or your underwear?

It is unwise to make a diagnosis of IBS on your own, without discussing it with your doctor. This is because some of the symptoms might be caused by a more serious condition, such as bowel cancer or inflammatory bowel disease (although these are much less likely than IBS). You must talk to your doctor if you:

  • lose weight
  • have symptoms in the night
  • find any blood mixed with the poo
  • have relatives with bowel cancer.

What Causes Irritable Bowel Syndrome?

IBS really is a mystery illness. The exact cause is unknown. There are probably several different causes acting together. Here are some of the theories.
Abnormal gut contractions. Our gut contains muscle in its wall, and this muscle is constantly contracting and relaxing to push undigested food and food waste along. Some people with IBS may have more of these gut contractions, or they may be clustered together abnormally.
Hypersensitivity to feelings in the gut. The gut sends messages along special nerves to the brain all the time, but normally the brain ignores these messages so we are not aware of them. In IBS these nerves may become more active, sending stronger messages, or the brain may not cancel them out as it normally would.
Gut distension and FODMAPS. Some carbohydrates and other substances in foods are not easily absorbed in the gut and just pass along it. These substances are known as FODMAPs (Fermentable Oligo-, Di- and Monosaccharides and Polyols) and include various food chemicals such as fructose, lactose and sorbitol (Journal of Gastroenterology and Hepatology 2010;25:252–258). As they pass through the gut, they can retain fluid and are acted on by gut bacteria to produce wind. FODMAPS are not the cause of IBS but they may provoke distension of the gut and therefore worsen IBS symptoms, especially in people who have hypersensitivity to gut sensations.
Stress response. Anyone who has ever taken an exam knows that anxiety causes diarrhoea i.e. it increases the normal gut contractions. Psychological stress and anxiety-provoking events trigger the release of stress hormones, and these affect the gut. People with IBS often say that it started after some stressful event in their life, and that it becomes worse when they are under pressure.
Gut infection. A bad gut infection (gastroenteritis) may be followed by IBS. This is called ‘post-infectious IBS’, and the pain can be severe.

How You Can Help Yourself

Diet. Thinking about the balance of your diet is a good first step. Are you taking excessive amounts of fibre, carbohydrates or fats? If so, adjusting the balance might prove helpful. Some people find that wheat or dairy products make their symptoms worse, so it might be worth avoiding either wheat or dairy for a month to see if it has any effect. A diet that avoids FODMAPS (see above) really helps in about 75% of people with IBS but has little benefit in some. This is a complicated diet that requires advice from a qualified dietician, so don’t try to do it on your own because you could end up with nutritional deficiencies.
If constipation is your main symptom, increasing fibre intake may help, but it does not help other symptoms. You can take various substances to increase fibre, mostly available in health food shops; for example, bran, ispaghula methylcellulose or sterculia. In fact, high-fibre diets based on bran or ispaghula can make symptoms worse in some people; this is less likely to happen with methylcellulose or sterculia.
Probiotics. We all have millions of ‘friendly’ bacteria in our guts. They are very important to our health. They help to detoxify the gut, to reduce inflammation, to boost our immune system and to reduce the risk of infection by bad disease-causing bacteria. Some studies have shown that in IBS the population of these friendly organisms is disturbed. Therefore, providing friendly bacteria (such as lactobacilli and bifidobacteria) and friendly yeasts (such as Saccharomyces boulardii) in the form of probiotics can be beneficial. Research studies indicate that probiotics are particularly helpful for bloating and wind.
Peppermint oil relaxes the muscle in the wall of the gut, i.e. it has an antispasmodic effect. It also has an antibacterial effect. The bacteria that live in the gut are responsible for producing gas, especially when the balance of bacteria in the gut is disturbed (as occurs in some people with IBS). Therefore, it is not surprising that peppermint oil helps to reduce both abdominal pain and discomfort and the feeling of bloating, as well as diarrhoea and constipation (Digestive and Liver Disease 2007;39:530–536).
Loperamide, which you can buy from pharmacies, is very effective if diarrhoea is your main symptom. However, it does not have much effect on abdominal pain or discomfort.
Mebeverine is another medication that can be bought from pharmacies. It is an ‘antispasmodic’ that relaxes the muscle in the wall of the gut and can help to reduce pain and cramping. It does not have much effect on diarrhoea or constipation.
Relaxation techniques. If your IBS is worse when you feel stressed, relaxation techniques are well worth investigating. Your local library will have books on relaxation, or you may find a class locally or look online.
Cognitive Behavioural Therapy can also help.

How Your Doctor Can Help

Your doctor has a key role in making sure that you have IBS and not any serious condition.
Amitriptyline and similar medications (so-called ‘tricyclic antidepressants’) can be an effective treatment for the pain and discomfort of IBS but require a prescription from your doctor. They are thought to work by inhibiting the pain messages that the gut sends to the brain. The downside is that they can make you drowsy (in which case you should not drive or operate machinery) and give you a dry mouth. They may not work straight away, so it is worth persevering with them for 4 weeks. They are usually continued for 6 months. (These medications are also used for depression, but for IBS the doses are lower and they provide a different effect.)

Will I Get Better?

IBS usually gradually improves. For example, a study in Bristol found that 5 years after their IBS was diagnosed, 68% of patients had no further symptoms (Lancet 1987;329:963–965). However, people with IBS often report that their gut remains sensitive, so symptoms may come back after any stressful life-event. It can take a long time to recover from IBS that occurs after a gut infection: one study found that after 6 years only 43% of patients had recovered completely (Gut 2002;51:410–413).


First published on: embarrassingproblems.com
Reviewed and edited by: Dr Kevin Barrett
Last updated: October 2020

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