Irritable bowel syndrome (IBS) is a chronic and debilitating functional gastrointestinal (GI) disorder characterized by a group of symptoms that affect the digestive tract. People with IBS tend to have a sensitive and reactive digestive system, and the function and movement of the bowel that is affected. There is no specific known cause or medical tests to diagnose IBS (1).


Who gets IBS?

IBS is the most common gastrointestinal condition worldwide, with a prevalence of 10-15% of the population in both North America and Europe (2). IBS affects as many as 13-20% of Canadians of all ages, race, and gender at any given time, but it is more common in women than men (3).


What are the common symptoms of IBS?

For people with IBS symptoms vary but typically include one or more of the following:

  • Abdominal pain
  • Bloating
  • Gas
  • Distention
  • Altered bowel habits between constipation and/or diarrhea or both

It is important to note, these symptoms aren’t an occasional annoyance for people with IBS, they are often frequent and with intensity to the extent that it interferes with day to day living.



What causes IBS?

The exact cause is still uncertain however, several theories exist that may contribute towards IBS, such as:

  • Gastrointestinal infection
  • Small intestinal bacterial overgrowth
  • Imbalance of gut bacteria
  • Antibiotic use
  • Physical and/or emotional stress
  • Food allergies or sensitivities
  • Poor diet
  • Abnormal gastrointestinal secretions and/or intestinal muscle contractions   
  • Genetics (1,3,4)


How is IBS Diagnosed?

There is no specific test to diagnose IBS. Part of the process is to rule out all other potential GI disorders. Keeping a food and symptom journal, documenting all foods and fluids consumed along with any GI related symptoms and when they occured is important to identify and remove trigger foods from the diet.


The standard diagnostic tool for IBS is the Rome IV criteria, which includes a recurrent abdominal pain on average for at least one day per week in the last three months associated with two or more of the following:

  • Pain related to defecation
  • Pain associated with a change in frequency of stool
  • Pain associated with a change in form (appearance) of stool

Criteria fulfilled for the last three months with symptom onset at least six months before diagnosis (5).



How is IBS managed?

Management requires understanding the underlying causes or possible triggers of episodes related to discomfort and then work to eliminate or minimize them. Symptoms can be successfully managed through diet, medication, and lifestyle changes or a combination of these approaches.


Diet and lifestyle therapies

  • eat regular, balanced meals of moderate portions;
  • limit fried and high fatty foods;
  • avoid common trigger foods such as: garlic, onion, lactose, gluten, caffeine, alcohol, added sugar, refined grains, processed foods/meats, artificial sweeteners;
  • consume fibre rich foods, including; beans, lentils, seeds, whole grains, fruit and vegetables;
  • drink plenty of fluids;
  • enjoy fermented foods; yogurt, kefir, kimchi, sauerkraut and kombucha;
  • take a probiotic – research has revealed there are specific strains of beneficial bacteria shown to relieve IBS related symptoms;
  • stress management.


A research based diet therapy for IBS is the low FODMAP diet (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). These are short chain carbohydrate containing foods that are poorly digested and absorbed in the gut which can trigger symptoms related to IBS (6). The diet involves a period of restricting specific foods for six to eight weeks to alleviate symptoms, followed by a gradual reintroduction phase to establish tolerance of FODMAP containing foods.  


Collaborating with a physician and registered dietitian to provide an individualized treatment plan, can help manage symptoms and improve quality of life with good adherence.



  1. Canadian Society for Gastrointestinal Research. Accessed via: https://www.badgut.org/information-centre/a-z-digestive-topics/ibs/.
  2. World Gastroenterology Organization. Irritable bowel syndrome: a global perspective. World Gastroenterology Organisation Global Guideline 2015.
  3. Fedorak RN et al. Irritable bowel syndrome in Canada. Incidence, prevalence, and direct and indirect economic impact. Canadian Journal of Gastroenterology. 2012;26(5):252-256.
  4. Lekha S. Irritable bowel syndrome: pathogenesis, diagnosis, treatment, and evidenced based medicine. World Journal of Gastroenterology. 2014;20(22):6759-6773.
  5. Rome IV Diagnostic Criteria for Functional Gastrointestinal Disorders (June 2016) Accessed via: https://theromefoundation.org/rome-iv/whats-new-forrome-iv/.
  6. Monash University. FODMAPs and Irritable Bowel Syndrome. Accessed via: https://www.monashfodmap.com/about-fodmap-and-ibs/.


Suzie Cromwell is a Registered Dietitian now working part-time at Elaho Medical Clinic. She completed her Bachelor of Science in Food, Nutrition and Health at UBC, and following her graduation she completed an extensive integrated internship with Fraser Health Authority at both Royal Columbian and Burnaby Hospitals. Suzie is registered with the College of Dietitians of British Columbia and is a member of Dietitians of Canada.
Her scope of expertise includes: healthy weight loss and maintenance, the prevention and management of various chronic diseases (including Diabetes, Kidney, and Cardiovascular disease), and the effective management of digestive issues (including IBS, IBD, and Celiac Disease); as well, she has a special interest in Sports Nutrition.



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