What is IBS?

Irritable Bowel Syndrome (IBS) is a common functional gut disorder that affects approximately 1 in 7 people. It is considered a disorder of gut–brain connection, meaning symptoms arise from changes in how the gut and nervous system communicate which results in a change in how the gut functions. It is important to note that with IBS, there is no structural damage to the gut and there is no disease.

IBS is long‑term, but it does not cause bowel damage or increase the risk of bowel cancer. Symptoms can vary from person to person and often fluctuate over time.

Common IBS symptoms

People with IBS may experience:

• Abdominal pain, cramping or discomfort

• Bloating and distention

• Diarrhoea, constipation, or a mix of both

• Increased gas or flatulence

• Urgency or feeling of incomplete bowel motions

Types of IBS

IBS is usually classified based on bowel habit:

• IBS‑D: diarrhoea‑predominant

• IBS‑C: constipation‑predominant

• IBS‑M: mixed diarrhoea and constipation

• IBS‑U: unclassified

Identifying your IBS type can help guide treatment and dietary strategies.

What causes IBS?

There is no single cause of IBS. Instead, it is thought to involve a combination of factors, including:

• Increased gut sensitivity (visceral hypersensitivity)

• Changes in gut motility (how fast food moves through the bowel)

• Altered gut–brain communication

• Changes in the gut microbiome which can arise from a change in diet or from taking antibiotics

• A history of gut infection (post‑infectious IBS)

• Stress and psychological factors

• Certain medications

• Family history or genetics

Because IBS is multifactorial, management often requires a personalised approach.

How is IBS diagnosed?

IBS is diagnosed based on symptoms, typically using Rome IV criteria, after other conditions such as coeliac disease, inflammatory bowel disease or bowel cancer have been ruled out. There is no single test for IBS and therefore blood tests and other investigations such as gastroscopies or colonoscopies will come back clear. A doctor, gastroenterologist or dietitian will assess your symptoms, medical history and any red flags that may require further investigation.

It is important to note that at-home DNA tests such as hair follicle tests for food allergies are not recommended as there is no scientific evidence to support these tests.

Managing IBS

Although there is no cure for IBS, symptoms can be effectively managed with the right support. Evidence‑based strategies may include, but are not limited to:

• Elimination diets, such as the low FODMAP diet

• Improving fibre type and intake

• Stress and nervous system regulation

• Probiotics

• Modifying eating behaviours and food routine

• Addressing movement and exericse

Because triggers and symptoms differ between individuals, a personalised approach is necessary for IBS management.

How a dietitian can help

Working with a qualified dietitian experienced in IBS can help you:

• Identify food and lifestyle triggers safely

• Follow the low FODMAP diet correctly whilst still ensuring adequate nutrient intake

• Improve symptom control without unnecessary restriction

• Build a sustainable, personalised diet that fits your lifestyle

With personalised care, many people with IBS experience significant symptom relief and improved quality of life.