Differentiating between IBD and IBS

Key Points

  • Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are different conditions that have some similar symptoms. 
  • IBD, most commonly Crohn’s disease or ulcerative colitis, is characterised by inflammation and damage to the gut while IBS is characterised by irregular bowel movements, abdominal pain and gas. 
  • Up to 30% of Australians have IBS, and some people living with IBD can also live with IBS. 
  • Treatment is completely different for the two conditions. Treating IBD focuses on reducing inflammation while treating IBS relies on reducing dietary triggers, managing stress and other psychological factors due to the gut-brain axis and use of some medications like antispasmodics. 

What is IBS? 

Irritable bowel syndrome (IBS) is a common disorder that affects the digestive system. It can cause symptoms such as: 

  • abdominal pain 
  • wind 
  • constipation and/or diarrhoea, and 
  • bloating. 

The intensity of symptoms can be different for each person and can negatively affect your social life, self-esteem, and ability to travel. They usually occur after a large meal or if you are under a lot of stress. 

In Australia, up to 30% of people have IBS, with the condition found more commonly in women. 

What is the difference between IBD and IBS

Inflammatory bowel disease (IBD) and IBS are two separate disorders of the gut. Because they are different conditions they require different treatment, so it is important to not to get them confused with each other and receive an accurate diagnosis. Performing tests on the bowel that measure if there is inflammation present is important to work out which treatment strategy is best to make you feel better. 

The similar acronyms for IBD and IBS and the fact that they both affect the digestive system often lead people to confuse the two. While both IBD and IBS are chronic (long-term) conditions, only IBD causes damage to the gut through inflammation. IBS is experienced through symptoms only without any injury to the gut. 

Common symptoms · Diarrhoea 
· Blood in stools 
· Frequent bowel movements 
· Fever 
· Fatigue 
· Weight loss 
Read more about Symptoms and IBD 
· Constipation 
· Diarrhoea 
· Abdominal pain 
· Wind 
· Bloating 
Diagnosis · Blood tests abnormal – anaemia, iron deficiency, raised inflammation markers 
· Faecal calprotectin test – abnormal 
· Colonoscopy – inflammation
Read more about Diagnosis and IBD 
· Blood tests normal 
· Faecal calprotectin test – normal
· Colonoscopy – no inflammation 
Treatment · Anti-inflammatory medication 
· Immunosuppressants 
· Diet changes 

Read more about Treatment and IBD
· Antidiarrhoea medication 
· Antispasmodics 
· Stool bulking medication 
· Diet changes 
· Psychological approaches 
Complications · Fistulae 
· Abscess 
· Bowel obstruction 
· Ulcers 
· Malnutrition 
· Anaemia 
· Surgery 
· Colon cancer (if the colon is involved)  
Read more about Complications of IBD 
Psychological impacts:
· Impaired quality of life,
· increased risk for anxiety,
· depression
· post-traumatic stress
· stigmatisation 
Read more about Psychological health and IBD 
· Chronic constipation and diarrhoea may cause haemorrhoids 
· No increased risk of colon cancer 
· Psychological Impacts: Impaired quality of life, increased risk for anxiety and depression, and stigmatisation 

What causes IBS?

Like with IBD, little is known about the cause of IBS, but many people with IBS have mentioned that symptoms appeared after gastroenteritis, food poisoning, infection, illness or chronic stress. IBS is more common in people with anxiety, depression, other mental health issues or a history of trauma. Stress and some foods may also aggravate IBS symptoms. 

There is also some evidence that the brain-gut connection is involved with IBS activity. The nerves that control the muscles in the gut become overly sensitive which leads to irregular bowel movements, bloating, pain and spasms. 

How is IBS diagnosed? 

Unlike with IBD, IBS can not be seen with any tests like colonoscopy. Diagnosis of IBS will depend more on your symptom history. However, you may require endoscopic, imaging or stool tests to rule out any other conditions that may be causing your symptoms. 

If you are concerned about any uncomfortable gut symptoms that keep on returning, speak with your doctor or an accredited practising dietitian. 

How is IBS treated? 

IBD and IBS are not caused by diet but many people with the conditions have found that diet can help with management. In many cases, making changes in your diet is the only strategy needed to remove or reduce symptoms for IBS. 

There are also some medications that directly address symptoms and some complementary therapies can help.  

Psychologists also use psychological therapies and may use gut-directed hypnotherapy.  

What type of diet can I follow to improve my IBS symptoms? 

There is no one size fits all when it comes to diet and managing IBS. A good first step is to start a food diary to help you find foods that trigger your symptoms and remove them from your diet. Be careful that the foods you are removing are replaced with other foods that can supply nutrition. 

It is also important to stay hydrated by drinking enough water as chronic diarrhoea can lead to dehydration. Drink enough to keep your urine light yellow to clear. 

You should also try to maintain a balanced and healthy diet. Some general tips on diet to improve symptoms during a flare-up include: 

  • Eating smaller meals more frequently throughout the day. 
  • Reducing how much greasy or high-fat foods you eat. 
  • Eating fewer foods containing lactose like milk and cream. 
  • Drinking less alcohol. 
  • Eating less gas-producing foods like onion, cabbage and cauliflower. 

Another diet your dietitian may recommend is a low FODMAP diet.  

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These are types of carbohydrate (sugar) which are sometimes not well absorbed in the small intestine and can lead to IBS symptoms.  

Your dietitian will lead you through an elimination process to help you identify which FODMAPs are triggering your symptoms so you can replace those foods in the future with ones that are gentler on your gut. Seek advice from a dietitian before making changes to your diet. 

Read more about Nutrition and IBD.  

How can I protect my mental health? 

IBS symptoms can be affected by how you are feeling, so it is important to look after your psychological wellbeing. You can seek help from a psychologist. 

Cognitive Behavioural Therapy (CBT): CBT can teach you coping strategies and has shown to help some people manage their anxiety. 

Gut-directed hypnotherapy: This approach has proven to be highly effective in managing pain caused by IBS and may even help reduce stress and improve immune function. 

Strategies to manage stress

  • speak to someone about how you are feeling either to a friend or health professional 
  • take the time for self-care which might include spending time with friends, fun activities or hobbies. 
  • exercise for 30 minuntes five times per week, and 
  • practice good sleeping patterns like going to bed and waking up at the same time. 

Read more about Psychological Health and IBD

Is it possible to have both IBD and IBS?

Yes, you can develop both conditions. Both IBD and IBS are difficult to diagnose so you may be diagnosed with them at different times. 

If you think you have IBS or IBD, speak with your doctor. If you would like help with your diet speak with an accredited practising dietitian or registered psychologist.  

Find a dietitian or psychologist.