Irritable bowel syndrome

Irritable bowel syndrome (IBS) is not a single disease; it is a group of symptoms that affect the digestive system. In people with IBS, the signals between the intestines and the brain are disrupted, causing the intestines to become overly sensitive and to overreact to certain triggers, particularly certain foods or stress. ^[1,2]

Types of IBS

There are four main types, classified by stool pattern:^[1]

• IBS with predominant diarrhoea (IBS-D)
• IBS with predominant constipation (IBS-C)
• IBS with mixed bowel habits - both diarrhoea and constipation (IBS-M)
• IBS unclassified - does not clearly fit another type (IBS-U)

Knowing your type is important because some treatments work better for certain types.

Risk Factors

You may be more likely to develop IBS if you:^[2]

• Are female
• Are under 40 years of age
• Have a family history of IBS
• Have a mental health condition such as depression, anxiety, or PTSD
• Have had a previous bacterial gut infection

Symptoms

The main symptom is abdominal pain or discomfort. Other common symptoms include: ^[1,2]

• Diarrhoea, constipation, or both
• Abdominal bloating or swelling
• Feeling full after only a small meal
• Excess gas
• Mucus in the stool
• A feeling that the bowel has not fully emptied after a movement

Symptoms come and go, and may be triggered by certain foods, stress, or mental health changes.

Diagnosis

IBS is usually diagnosed based on your symptoms, medical history, and a physical exam. Tests may be ordered to rule out other conditions: ^[1,4]

• Blood tests
• Stool tests
• Colonoscopy: a thin, flexible camera examines the bowel lining

Treatment

There is no cure for IBS, but treatment can significantly reduce symptoms. Treatment is tailored to your type of IBS. ^[2,4]

Diet Changes

• Avoid foods that trigger your symptoms.
• Drink more water throughout the day.
• Follow a low-FODMAP diet for up to 6 weeks (see the Low Fermentable Carbohydrate Diet fact sheet). FODMAPs are sugars that are hard for some people to digest.^[3]
• Eat more fibre, especially if you have IBS-C.
• Eat 5-6 small meals at regular times each day rather than large, irregular meals.

Medications

• Fibre supplements: for constipation
• Anti-diarrhoeal medications: to help control loose stools
• Antispasmodics: to reduce cramping
• Antidepressants: to help with gut-brain communication and pain

Other Approaches

• Talk therapy or counselling
• Gut Hypnotherapy
• Working with a dietitian for a personalised food plan
• Stress management: regular exercise, good sleep, and relaxation techniques

Managing IBS

Eating and Drinking

• Eat a healthy, balanced diet.
• Eat 5-6 small meals at consistent times each day. Avoid large meals.
• Keep a food diary to track symptom triggers.
• Avoid foods that worsen symptoms. Common culprits include dairy products, caffeine, carbonated drinks, and high-sugar foods.
• Drink enough fluid to keep your urine pale yellow.

Alcohol

• Avoid alcohol if your doctor advises it, or if you are pregnant.
• If you drink, limit to 1 standard drink per day for women, 2 for men.

General

• Take medications as directed.
• Exercise for at least 150 minutes per week; this supports bowel regularity and reduces stress.
• Keep all follow-up appointments with your health care team.

WHEN TO SEEK MEDICAL ATTENTION

Resources

• Irritable Bowel Information and Support Association of Australia (IBIS): www.ibisaustralia.org.au - Patient information, support, and community for people with IBS
• Gastroenterological Society of Australia (GESA): www.gesa.org.au - Find a gastroenterologist and clinical resources
• Dietitians Australia: www.dietitiansaustralia.org.au - Find a dietitian experienced in the low-FODMAP diet
• Monash University FODMAP Diet App: www.monashfodmap.com - Evidence-based FODMAP diet resources developed at Monash University, Melbourne
• Jean Hailes for Women's Health: www.jeanhailes.org.au - Digestive health and IBS resources

REFERENCES

1.Lacy BE, et al. (2016). Bowel Disorders. Gastroenterology, 150(6), 1393-1407.

2.Ford AC, et al. (2018). Irritable bowel syndrome. The Lancet, 392(10146), 513-527.

3.Gibson PR, Shepherd SJ. (2010). Evidence-based dietary management of functional gastrointestinal symptoms: the FODMAP approach. Journal of Gastroenterology and Hepatology, 25(2), 252-258.

4.Gastroenterological Society of Australia (GESA). (2023). IBS clinical update.https://www.gesa.org.au

5.Irritable Bowel Information and Support Association of Australia (IBIS Australia). (2024). About IBS.https://www.ibisaustralia.org.au