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What is irritable bowel syndrome (IBS)?
Irritable bowel syndrome (IBS) is a condition that affects the colon (large bowel), and while it is not considered life-threatening or dangerous, it can be very uncomfortable. IBS is common, and affects around 3 out of every 10 people. Women are more likely than men to be affected.
What are the symptoms of irritable bowel syndrome?
Some of the key symptoms of IBS include:
- abdominal pain or discomfort
- stomach bloating
- chronic diarrhoea or constipation, or alternating between the two
Some people also report whitish mucus in the faeces (poo), feeling their bowel movement was incomplete — even after a poo — and nausea.
Often, the pain of IBS can be relieved by passing wind or faeces.
What causes irritable bowel syndrome?
While the exact cause of IBS is not clear, certain things are known to trigger symptoms in people who tend to experience IBS. Some common IBS triggers include diet, stress, infection and medications.
Many people with IBS notice that some foods make their symptoms worse, but these 'trigger foods' differ from one person to the next.
Your IBS symptoms might have started after an infection, such as gastroenteritis or ‘gastro’, a period of increased stress, or a medicine. Some antibiotics antacids and pain medicines can affect symptoms. See your doctor to check whether these may have triggered your symptoms, and what treatment best suits your condition.
How is irritable bowel syndrome diagnosed?
Often your doctor can diagnose IBS just by asking you some key questions about your symptoms.
A diagnosis of IBS can be made if the following criteria, known as the Rome IV, are met.
Recurrent abdominal pain (at least 1 day each week in the past 3 months) associated with at least 2 of these symptoms:
- pain related to bowel motion
- a change in the frequency — more frequent or less frequent — of when you poo
- a change in the consistency or appearance of faeces
- Symptoms must be present for 6 months before a diagnosis of IBS is made
If you are over 40 years old, have a family or personal history of bowel cancer or if your doctor thinks that your symptoms might be associated with another health condition, they might carry out or refer you for one or more of the following tests:
- a general health check-up
- blood tests (to check for coeliac disease)
- stool (poo) test
- sigmoidoscopy or colonoscopy (a small camera inserted into the bowel through the anus)
Should I see my doctor about irritable bowel syndrome symptoms?
It is important to see your doctor if you develop symptoms. They may check for other conditions before diagnosing you with IBS.
See your doctor if:
- you are concerned about your symptoms, and if they are severe or ongoing
- if you notice any blood in your stools
- if you have unexplained or unintentional weight loss
- you have fever or severe diarrhoea
These symptoms are unlikely to be caused by IBS, and so it is important that a health professional checks them to exclude a more serious condition.
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How is irritable bowel syndrome treated?
There is a wide range of proven treatments for IBS, including prescribed medicines and over-the-counter medicines, as well as approaches that do not involve drugs.
Often, a dietary change is enough to improve symptoms — this should ideally be made in conjunction with a health professional such as a dietitian who can make sure you don’t miss out on any key nutrients while you are trying to identify and exclude foods that trigger your IBS.
In Australia there are no medicines designed specifically for IBS. However in certain cases, a doctor may prescribe medicines — including antispasmodics, antidiarrhoeals, antidepressants or antibiotics — that have symptom-relieving side-effects. In addition, some non-prescription products such as peppermint oil might be recommended if they have been medically proven to improve symptoms.
Your doctor will take several factors into account before recommending a treatment, including whether your IBS tends to involve diarrhoea or constipation, or alternate between the two.
Over-the-counter probiotics may have a role in improving symptoms, although more research is required before we really understand the strain and dose that will provide the greatest benefit.
There are some behavioural and psychological therapies that have been shown to improve symptoms of IBS. These can be particularly helpful if you notice that your IBS is triggered by stress or anxiety.
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How can I reduce the symptoms of irritable bowel syndrome?
Although IBS cannot be prevented, symptoms can be reduced, and healthy lifestyle habits can often help.
Careful changes to your diet can help reduce the symptoms of IBS.
One tip that may help you reduce your symptoms is to simply increase your intake of high-fibre foods.
It is best to slowly increase your fibre intake up to the recommended daily dose to avoid bloating and wind-related discomfort.
The current recommendation for adults is to eat at least 25g to 30g of fibre each day. In a typical day, try to include 1 serving of high-fibre breakfast cereal in the morning, at least 5 servings of fruit and vegetables throughout the day and 3 servings of dairy foods — if you are lactose intolerant, chose a dairy-free or low lactose alternative — as well as 6 to 8 glasses of water.
If this is difficult for you, ask your pharmacist for a soluble fibre supplement, such as psyllium.
Some foods and drinks commonly trigger IBS, so try to reduce your intake of the following to see if this helps:
- gas-producing foods, such as onion, cabbage, Brussels sprouts, dried beans, lentils and cauliflower
- foods with lactose (milk sugar) such as milk, ice-cream, some yoghurts
- alcoholic drinks
- artificial sweeteners in food and drink, such as aspartame, sorbitol and mannitol
A dietitian can help you identify your individual triggers and can work with you to create a balanced diet that suits you.
Sometimes, a low FODMAPs diet is recommended. FODMAPs is short for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are the chemical names for different sugars that are poorly absorbed in the intestine which for some people can trigger symptoms of IBS.
Other proven strategies to reduce IBS symptoms include physiotherapy to help address pelvic floor dysfunction , hypnotherapy and relaxation exercises.
Are there complications of irritable bowel syndrome?
While IBS can be painful, it is reassuring to remember that the condition does not cause long-term damage to the colon or other parts of the digestive system. IBS also does not directly cause other physical health problems.
Although IBS is often a mild condition that can be well-managed by diet and other lifestyle improvements, it can significantly impact some people's quality of life, and can be stressful to manage. Flow-on effects can include depression and anxiety, migraine, fibromyalgia and/or chronic fatigue syndrome.
If IBS is causing you to feel down, anxious or upset, there are IBS-specific psychological support services. Talk to your GP about whether they are right for you.
A small number of people with IBS may experience faecal incontinence. The Continence Foundation of Australia can help with strategies where this is due to constipation or diarrhoea. Call their toll-free helpline for advice on 1800 330066.
Resources and support
For more information and support, try these resources:
- Monash University FODMAPs and Irritable Bowel Syndrome
- The Continence Foundation of Australia — National Continence Helpline
- Dietitians Australia — A guide to IBS
Do you prefer to read in a language other than English? The Continence Foundation of Australia has fact sheets on healthy diet and bowels translated into over 25 different languages.
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Last reviewed: September 2020