IBS (Irritable Bowel Syndrome) and IBD (Inflammatory Bowel Disease) are two gastrointestinal conditions that are frequently confused – and understandably so.  

They share many symptoms, including abdominal pain, altered bowel habits, bloating, urgency, and fatigue. However, beyond these surface similarities, they are fundamentally different conditions.  

Understanding the distinction is important for appropriate management, long‑term health planning, and quality of life. 

What is IBS? 

Irritable Bowel Syndrome is a disorder of gut–brain interaction. This means symptoms arise from altered communication between the gut and the nervous system, rather than from visible inflammation or tissue damage. 

IBS is diagnosed based on symptom patterns (Rome criteria) once other conditions have been ruled out. Tests such as blood work, stool markers, colonoscopy, and imaging are typically normal. 

Symptoms are real and can be severe, driven by: 

▪ visceral hypersensitivity (heightened pain perception) 

▪ altered gut motility 

▪ stress and nervous system responses 

▪ previous gut insults (infection, antibiotics, surgery) 

Because IBS does not damage the bowel or increase cancer risk, our clients often report that after a ‘normal colonoscopy’, they feel relieved but confused. Their symptoms persist, and their symptom burden affects their quality of life. 

What is IBD? 

Inflammatory Bowel Disease is an immune‑mediated inflammatory disease. The immune system drives ongoing inflammation in the gut, leading to visible injury of the intestinal lining. 

The two main types are: 

▪ Crohn’s disease (can affect any part of the GI tract, often patchy) 

▪ Ulcerative colitis (affects the colon, continuous inflammation) 

IBD is diagnosed using: 

▪ colonoscopy and gastroscopy with biopsy 

▪ imaging (MRI or CT) and abdominal ultrasound 

▪ blood inflammatory markers  

▪ stool markers (faecal calprotectin) 

Unlike IBS, IBD can lead to long‑term complications such as strictures, fistulas, anaemia, malnutrition, surgery, and increased colorectal cancer risk. 

Why symptoms can look similar 

Both conditions involve alterations in the gut environment and microbiome, and both often follow a relapsing–remitting course. Stress, infection, diet, and medications can worsen symptoms in either condition. 

Importantly, symptom severity does not reliably reflect inflammation. This is why IBS pain can feel just as debilitating as active IBD — even in the absence of tissue damage. 

Can someone have both IBS and IBD? 

Yes. A significant proportion of people with IBD in remission also meet diagnostic criteria for IBS. This overlap can complicate symptom interpretation and highlights the need for careful, individualised management. 

Accurate diagnosis matters. A missed or delayed diagnosis can lead to: 

▪ inappropriate treatment 

▪ prolonged trial‑and‑error dietary restriction 

▪ increased risk of malnutrition 

▪ delayed medical therapy in IBD 

Early involvement of both gastroenterology and specialist dietetics is critical — for symptom management in IBS and for preventing complications in IBD. 

Our Help Yourself Dietitians recently conducted a study to find out what mattered most to people with Crohn’s disease about dietary management. They told us that what mattered most was that the dietitian was responsive to their needs and preferences and factored these into their dietetic care. We can offer you the same attentive and responsive care. 

Take home 

IBS and IBD are different conditions with different causes, risks, and treatments — but both have a significant impact on physical and psychological wellbeing. Neither should be minimised. 

What matters most is getting the right diagnosis, followed by evidence‑based AND personalised care that addresses symptoms, nutrition, mental health, and long‑term outcomes.