Melbourne Dietitian & Nutritionist

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What is IBS (Irritable Bowel Syndrome)?

Emma Keenan Dietitian

Having a deeper understanding of IBS can be beneficial for you or someone you know in the following ways:

  1. Ensuring an accurate diagnosis is obtained, rather than relying on self-diagnosis

  2. Gaining awareness of the available options for managing IBS symptoms

  3. Developing empathy and understanding for individuals living with IBS

What is Irritable Bowel Syndrome?

Irritable bowel syndrome (IBS) is classified as a functional gastrointestinal (GI) disorder.

But, what exactly is a functional GI disorder?

In essence, a functional GI disorder is a condition where the normal function of the gastrointestinal system becomes impaired. The term ‘normal functioning’ encompasses various aspects, including:

  • The peristaltic movement of the intestines.

  • The sensitivity of the intestinal nerves.

  • The intricate communication between the gut and the brain, known as the gut-brain axis.

  • The regulation of these functions by the brain.

    It is crucial to note that functional GI disorders do not involve any structural damage to the gastrointestinal tract. Diagnosis of functional GI disorders primarily relies on symptom criteria and a meticulous process of excluding potential structural causes.

So, what sets a structural gastrointestinal disorder apart?

A structural gastrointestinal disorder involves abnormalities or structural damage to the GI tract, which can be visualised and diagnosed through procedures like endoscopy, gastroscopy, medical imaging, or blood tests. For example, conditions such as coeliac disease, inflammatory bowel diseases Crohn’s and colitis, reflux, or diverticular disease exhibit identifiable GI tract abnormalities, often detectable through endoscopy or supported by specific blood tests.

Endoscopy, a procedure in which a slender tube equipped with a camera and light is introduced into either the mouth (gastroscopy) or the anus (colonoscopy), allows medical professionals to visually inspect the gastrointestinal tract for any signs of damage and obtain tissue biopsies if necessary.

Who Develops IBS?

Irritable bowel syndrome is a very common gastrointestinal condition, affecting approximately 1 in 7 individuals. IBS is a condition that can manifest at any age, encompassing both children and the elderly. Typically, irritable bowel syndrome tends to be diagnosed before the age of 40, with fewer diagnoses occurring after the age of 50. Several factors are thought to contribute to this trend:

  • Prompt Diagnosis: Individuals often seek medical evaluation at symptom onset, increasing the likelihood of being diagnosed at an earlier age.

  • Improved Diagnostic Methods: Advancements in diagnostic techniques may have led to earlier detection of irritable bowel syndrome.

  • Self-Management: Older individuals may have developed effective strategies for managing their symptoms over time.

  • Natural Symptom Changes: It’s worth noting that IBS symptoms may naturally diminish as time progresses.

Moreover, IBS tends to disproportionately affect women, with approximately 67% more women experiencing IBS compared to men. However, these gender differences may be attributed in part to variations in healthcare-seeking behaviours between the genders.

What are the symptoms of IBS?

Irritable bowel syndrome (IBS) manifests with common symptoms that may resemble those of more serious medical conditions. This underscores the significance of obtaining a professional diagnosis from a doctor.

Frequently encountered IBS symptoms include:

  • Bloating

  • Abdominal distension

  • Constipation

  • Diarrhoea

  • Changing bowel habits (alternating between constipation and diarrhoea)

  • Urgency to poo

  • Excessive flatulence (gas)

  • Lower abdominal pain

These symptoms can vary in intensity, ranging from mild to severe. Importantly, IBS symptoms can significantly impact various aspects of an individual’s daily like, including:

  • Work-Life: Resulting in sick days, reduced productivity, and extended time spent in the bathroom.

  • Relationships: Influencing relationships with friends and family.

  • Sexual Relationships: Potentially affecting intimate relationships.

  • Social Life: Pertaining to challenges such as dining out, bathroom availability and discomfort.

  • Body image: Relating to concerns about stomach distention.

  • Mental health: With potential links to depression, anxiety, and stress.

  • Sleep Patterns: Impacting sleep quality.

  • Fatigue: Contributing to a sense of tiredness.

  • Fear of travel: Potentially limiting travel or long journeys.

  • Coping strategies: Often requiring the development of strategies to normalise bowel function.

It’s important to recognise that IBS symptoms can overlap with those of several serious conditions, including:

  • Coeliac disease

  • Inflammatory Bowel Disease (Crohn’s Disease and Ulcerative Colitis)

  • Diverticular Disease

  • Endometriosis

  • Pancreatic Exocrine Insufficiency

  • Endocrine Disorders

  • Bile Salt Malabsorption

  • Pelvic Floor Disorders

  • Intestinal Cancers

    What are red flag symptoms?

    Common symptoms of IBS overlap with other more serious conditions. It is important to understand what the “red flag” symptoms of these conditions are. If you have any of the following symptoms, please see your GP for their medical opinion and further investigations.

  • Family history of bowel diseases

  • Unexplained weight loss

  • Bleeding from rectum, blood in poo

  • Age 50+

  • Persistent daily diarrhoea

  • Fever

  • Nocturnal bowel motions (one that wakes you from your sleep)

  • Recurring vomiting

  • Severe or progressive symptoms

    What causes IBS?

    The cause of irritable bowel syndrome and other functional bowel disorders is unclear. There are likely many factors that play a role in the development of IBS these may include:

  • Changes in gut bacteria

  • Stress and anxiety triggering symptoms (gut-brain axis)

  • Changes in gut motility (how the gut contracts to move food through the GI tract) are either increased (diarrhoea) or decreased (constipation)

  • Increased gut sensitivity makes normal movements of the gut wall (stretching, or expanding as food moves through) uncomfortable or painful

  • Post-infectious IBS may start after a gut infection such as gastro (gastroenteritis)

Diagnosing irritable bowel syndrome

Irritable bowel syndrome should be diagnosed by a medical doctor. Diagnosis is based on symptoms that fulfil the Roma IV Criteria and tests that rule out more serious conditions.

IRRITABLE BOWEL SYNDROME
        Diagnostic criteria*              

        Recurrent abdominal pain on average at least 1 day/week in the last 3 months, associated with two or more of the following criteria:

  1. Related to defecation

  2. Associated with a change in frequency of stool

  3. Associated with a change in form (appearance) of stool

          * Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis

Diagnostic criteria for IBS subtypes

IBS-C (IBS with predominant constipation): more than 25% of bowel movements Bristol Stool chart type 1 or 2 and less than 25% bowel movements Bristol Stool chart type 6 or 7.

IBS-D (IBS with predominant diarrhoea): more than 25% bowel movements Bristol Stool chart type 6 or 7 and less than 25% bowel movements Bristol Stool chart type 1 or 2.

IBS-M (IBS with mixed bowel movements): more than 25% bowel movements Bristol Stool chart types 1 or 2 and more than 25% bowel motions Bristol Stool chart type 6 or 7.

IBS-U (IBS unclassified): People who meet the diagnostic criteria for IBS but whose bowel habits do not fit into the above categories.

Common tests used to rule out other conditions may include:

  • Blood tests

  • Stool tests

  • Endoscopy

Tests that are widely available but not recommended for IBS diagnosis include:

  • Breath tests

  • IgG food intolerance tests

  • Faecal microbiota tests

  • Intestinal permeability tests

treatments for IBS

There are many treatment options available to manage IBS symptoms. Someone with irritable bowel syndrome may benefit from using one or more strategies to manage their symptoms.

Dietary Interventions:

  • Discovering and modifying the intake of trigger foods e.g. alcohol, spicy foods, caffeine

  • Exclusion processes e.g., low FODMAP diet

  • Modifying fibre intake

  • Modifying meal patterns and portion sizes

  • Fibre supplements

Psychological therapies

  • Cognitive behavioural therapies

  • Gut-directed hypnotherapy

  • Biofeedback therapy

Lifestyle Interventions:

  • Exercise

  • Sleep

Medications that target:

  • Diarrhoea

  • Constipation

  • Pain

Supplements:

  • Probiotics (not all probiotic supplements are evidenced for IBS)

  • Herbal supplements

Top reasons to work with a Dietitian specialising in IBS

A dietitian specialising in the dietary management of irritable bowel syndrome can:

  1. Ensure the least restrictive dietary pattern by avoiding removing whole food groups unnecessarily

  2. Maximise the probability of achieving favourable results

  3. Efficiently alleviate the severity of your symptoms

  4. Save you time and money

  5. Provide you with the knowledge to independently manage your symptoms

Delve Deeper

What is the low FODMAP Diet? — St Kilda Dietitian & Nutrition (emmakeenandietitian.com.au)

Let's Have a Poo-versation — St Kilda Dietitian & Nutrition (emmakeenandietitian.com.au)

How are farts made? — St Kilda Dietitian & Nutrition (emmakeenandietitian.com.au)