What is IBS?

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Irritable bowel syndrome (IBS) is one of more than 20 functional gastrointestinal disorders.

The term “functional” implies that the affected person has symptoms related to the bowel (gut), yet all the pathological tests (biochemical or structural) that are conducted come back as normal. 

IBS is a recurring, chronic gastrointestinal disorder that’s characterised by:

  • Unexplained abdominal discomfort and/or pain.
  • Changes in bowel habit and/or consistency.

An IBS diagnosis is largely based on symptoms due to the lack of positive pathological tests.

Gastroenterologists use the Rome IV criteria to diagnose IBS, and the diagnosis is made if two or more of the following characteristics are present:

  • Improvement with defecation (i.e. going to the toilet).
  • Onset of gastrointestinal symptoms associated with a change in frequency of stool (number of times you need to go to the bathroom).
  • Onset of gastrointestinal symptoms associated with a change in form (appearance) of stool.

Typically, people with IBS would get up in the morning feeling fine, but as the day progresses, the bloating, pain and/or discomfort will start and intensify.

This can affect the person’s quality of life, both professionally and socially. 

There are four subtypes of IBS:

  • IBS-C = IBS-Constipation
  • IBS-M = IBS-Mixed (constipation and diarrhoea)
  • IBS-D = IBS-Diarrhoea 
  • IBS-U = IBS-Unspecified (final diagnosis hasn’t yet been made)

Subtyping of IBS into IBS-C, IBS-M, IBS-D or IBS-U is dependent on the person ’s report of the frequency of stool types based on the standard Bristol Stool Scale:

  • Type 1: Separate hard lumps like nuts (hard to pass)
  • Type 2: Sausage-shaped, but lumpy
  • Type 3: Like a sausage, but with cracks on the surface
  • Type 4: Like a sausage or snake, smooth and soft
  • Type 5: Soft blobs with clear-cut edges
  • Type 6: Fluffy pieces with ragged edges, a mushy stool
  • Type 7: Watery, no solid pieces, entirely liquid

Who gets irritable bowel syndrome (IBS) and how common is it?

Since many people with irritable bowel syndrome (IBS) don’t report their symptoms to doctors, it's difficult to say how many people are living with the condition. However, in most countries, the prevalence is estimated to be between 9% and 23% of the population. 

In South Africa, the prevalence of IBS is estimated to be below 8% of the population, according to a study conducted by Lovell and Ford in 2015. But the numbers were based on a study conducted as far back as 1984. Therefore, we really don’t know how many South Africans currently suffer from IBS.

Being female, being between the ages of 30 and 45, and having a family history of IBS may place you at higher risk for the condition. 

Course and prognosis of irritable bowel syndrome (IBS)

For most people affected by irritable bowel syndrome (IBS), it’s a chronic problem that swings between remission and suffering. For example, a person may have severe symptoms for a period of time and then feel well for several months or even years. Other people have very mild symptoms that come and go, whereas some can have severe symptoms that affect their quality of life on a daily basis. 

Therefore, there’s no consensus regarding the expected duration of IBS and symptoms may change over time. It’s important to note that most people are never cured of IBS. Dietary changes with or without medication could assist in reducing the frequency and/or severity of symptoms.

Factors that make IBS better or worse

Stress, anxiety and depression don’t cause IBS, but they can increase the frequency and severity of symptoms. For this reason, it’s important to address these mental-health problems through therapy and/or medical treatment. This will help to improve your symptom management and quality of life.

A poor diet (i.e. a westernised diet that’s low in fibre, high in fat and saturated fat, high in sugar and salt, and low in fruit and vegetables) doesn’t cause IBS, but it can certainly exacerbate the symptoms. Adopting a gut-healthy diet is important to address the symptoms of IBS (constipation, diarrhoea, bloating and heartburn).

It will also help to promote the growth of beneficial gut flora. 

Not getting enough sleep and being sedentary can also make managing your IBS symptoms very difficult. Exercise daily, if you can, and make a point of getting sufficient sleep (7 - 8 hours a night).

Possible complications of IBS

Long-term constipation may develop into faecal impaction. This is when the colon becomes blocked by a mass of stool that can't be moved by colon contractions. Faecal impaction can cause pain and vomiting, and may require emergency treatment or hospitalisation. Faecal impaction is a fairly common complication of long-term constipation.

Dehydration and electrolyte imbalances may also occur from untreated diarrhoea. Note that electrolyte imbalances can be life threatening if left untreated. 

A large proportion of people with IBS also avoid certain foods as they perceive their symptoms to be directly related to the food. Therefore, they may not get enough of the nutrients they need for optimal health, leading to malnourishment and possible eating disorders. 

Warning signs of a possible IBS flare-up 

People with IBS can anticipate a flare-up if they’re going through a stressful time at work or at home, or when their diet isn’t optimal.


IBS isn’t a serious disease as such, and it doesn’t require surgery. However, it can have a significant impact on quality of life (both professionally and socially) as well as self-esteem. Research has shown that employees with IBS spend more days in bed compared to those without IBS. It affects their productivity and results in higher health-care costs. 

When can you return to work or school?

People with severe symptoms may miss days from work or school. However, those with mild or moderate symptoms are often able to power through the day.  Most people with severe IBS symptoms can return to work or school when their symptoms have improved.

Read more:
Symptoms of IBS

Reviewed by Kim Hofmann, registered dietitian, BSc Medical (Honours) Nutrition and Dietetics, BSc (Honours) Psychology. January 2018.

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