Understanding Irritable Bowel Syndrome (IBS)

What is IBS?

IBS is a common digestive disorder that affects millions of people worldwide including approximately 30% of Australians. It is a chronic condition that effects the large intestine, leading to uncomfortable symptoms such as bloating, wind, diarrhea, and constipation. Whilst IBS is not inherently dangerous and does not cause permanent damage to the intestines or increase the risk of serious conditions like cancer, it can significantly affect a person’s quality of life and so is not something to be ignored.

Symptoms of IBS

The symptoms of IBS vary from person to person and can range from mild to severe. Common symptoms include:

• Abdominal pain, usually experienced as cramps which are relieved by going to the toilet and opening your bowel

• Bloating and excessive wind

• Diarrhea, constipation, or a combination of both

• Nausea

• Mucus in the stool or

• A sensation of incomplete bowel movements

You do not need to have all of these symptoms to have IBS.

These symptoms may be triggered or worsened by eating certain foods, experiencing stress, or hormonal changes. Women, in particular, may notice an increase in symptoms around their menstrual cycle.

Diagnosis of IBS

IBS can be diagnosed by your General Practitioner (GP). It is a diagnosis of exclusion meaning that other more serious conditions need to be ruled out first.

Other conditions with similar symptoms might include food allergies, coeliac disease, inflammatory bowel disease, gut infections and bowel cancer.

If you are losing weight without trying, have fevers, blood in your stool, severe diarrhoea or a strong family history of bowel cancer, you may need to have more extensive tests including blood tests, stool tests, imaging and possibly a gastroscopy and colonoscopy to rule out more serious causes of your symptoms.

If you do not have any of these more serious symptoms above, then your GP can likely make a diagnosis of IBS without any further testing using the Rome IV Criteria.

The Rome IV criteria require recurrent abdominal pain occurring at least one day per week in the last three months, associated with at least two of the following:

• Pain related to defecation

• Pain associated with a change in stool frequency

• Pain associated with a change in stool form (appearance)

Causes and Triggers of IBS

The exact cause of IBS remains unknown. However, there are several factors which may contribute to its development. These include a change in the balance of the gut bacteria such as after an episode of gastroenteritis, food position, infection, or illness. Stress, and anxiety can also be a contributing factor to IBS as the gut and brain are closely connected through the gut-brain axis.

There can also be a hypersensitivity of the nervous system in the digestive system causing the digestive tract to overreact to normal digestive processes and diarrhoea to ensue. Some people may have abnormal intestinal contractions leading to diarrhoea and constipation.

It is also known that food intolerances and sensitivities such as diary, gluten and fermentable oligosaccharides, disaccharides, monosaccharides and polyols can also trigger IBS symptoms in some individuals.

Recent research has suggested a possible association between IBS and endometriosis. Endometriosis is a condition where tissue similar to the lining of the uterus grows outside the uterus. Studies indicate that women with endometriosis have a higher prevalence of IBS symptoms, possibly due to shared mechanisms such as chronic inflammation, altered gut motility, and heightened pain sensitivity.

Management and Treatment

Although there is no cure for IBS, it can be effectively managed through lifestyle and dietary changes.

Dietary Changes

• Low-FODMAP Diet: FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) are types of carbohydrates that can trigger IBS symptoms. Reducing intake of high-FODMAP foods like onions, garlic, beans, and certain fruits can help. This is very difficult without the input of an experienced dietitian who will usually recommend an elimination type diet whereby these foods are eliminated from the diet for 6 weeks and then slowly re-introduced to see where your intolerances lie and how much of certain foods you can tolerate.

• Increase Fiber Intake: Soluble fiber (found in oats, bananas, and carrots) can help with constipation, but too much insoluble fiber (found in whole grains) may worsen symptoms.

• Stay Hydrated: Drinking plenty of water supports digestion and prevents constipation.

• Avoid Trigger Foods: Dairy, caffeine, alcohol, and spicy foods can trigger IBS symptoms in some individuals.

Lifestyle Adjustments

• Pelvic Floor Physiotherapy: For individuals with IBS-related pelvic floor dysfunction, working with a pelvic floor physiotherapist can improve bowel control, reduce straining, and alleviate bloating and discomfort. Techniques such as biofeedback and targeted exercises may be beneficial.

• Regular Exercise: Physical activity promotes healthy digestion and reduces stress.

• Stress Management: Practices like meditation, deep breathing, and yoga can help manage stress-related IBS flare-ups. If anxiety is an issue, a psychologist can be extremely beneficial.

• Adequate Sleep: Poor sleep can worsen IBS symptoms, so maintaining good sleep hygiene is essential.

Evidence-Based Medical Treatments

For patients with moderate to severe symptoms, medical treatments may be necessary. Evidence-based approaches include:

• Antispasmodics e.g., Hyoscine to help relieve abdominal cramping and pain.

• Laxatives (non-stimulant) e.g., Polyethylene glycol, Psyllium to help relive constipation.

• Antidiarrheal Agents e.g., Loperamide to relieve diarrhoea or faecal urgency.

• Probiotics (e.g., Bifidobacterium, Lactobacillus strains): Some evidence suggests they can improve gut microbiota balance and reduce symptoms. Use is usually limited for 3 months only.

• Peppermint oil. E.g. Mintec for gas or bloating

• Tricyclic Antidepressants to help reduce abdominal pain.

• Other antidepressants such as Selective Serotonin Reuptake Inhibitors for coexisting anxiety or depression.

• Assistance from a dietitian for a FODMAPS diet

• Assistance from a psychologist for cognitive behavioural therapy and gut-directed hypnotherapy.

Take Home Message

IBS is a common condition which can have a significant impact on your quality of life. It is very manageable, but a personalised approach is necessary. The most effective strategy is to identity your triggers such as stress or certain foods and try to manage these.

References

1. Health Direct https://www.healthdirect.gov.au/irritable-bowel-syndrome-ibs [03/03/25]

2. Dietitians Australia https://dietitiansaustralia.org.au/health-advice/irritable-bowel-syndrome-ibs [03/03/25]