Crohn's disease

Written by Becky Banham
Becky Banham
Nutritionist Resource Content Team

Last updated 12th July 2023 | Next update due 11th July 2026

Crohn’s disease is a condition in which parts of the gut and digestive system become inflamed. Here, we'll explore Crohn’s disease, highlighting the treatment available and whether a ‘Crohn’s diet’ can affect the symptoms.

What is Crohn’s disease?

Crohn’s disease is one of two conditions known collectively as IBD (inflammatory bowel disease), the other being ulcerative colitis. While the inflammation caused by Crohn’s can often be mild, many cases experience severe pain. People suffering the more severe symptoms will often need strong medication or an operation to remove the affected part of the intestine.

Symptoms can include:

  • diarrhoea
  • abdominal pain
  • fatigue
  • weight-loss
  • blood/mucus in the faeces

It's a long-term illness which, according to Crohn's & Colitis UK, affects more than 100,000 people in the UK, and millions more worldwide.

How Crohn’s disease affects the body

Crohn’s disease can affect any part of the gut, the most common areas being the lower part of the small intestine or the top of the colon. While some people find that only the colon is affected (similarly to ulcerative colitis), others may find Crohn’s has affected multiple parts of the gut.

In terms of the intestine, the mildest form of Crohn’s can result in small ulcers and patches of inflammation within the intestine lining. In more severe cases of Crohn’s disease, the ulcers grow to a larger size, becoming much deeper. The inflammation can thicken the intestine, making it difficult for digested food to pass through.

Sometimes, these large ulcers break through the intestine wall. This can cause an abscess outside of the bowel, known as a fistula - this can increase the risk of the infection spreading to nearby parts of the body, most commonly occurring around the anus.

Nutrition professionals who can help with Crohn's disease:

Crohn’s diagnosis

Your GP may suspect you have Crohn’s disease if you have a family history of IBD. They may also suspect the condition if you are a young adult and have been experiencing symptoms such as unintended weight-loss, abdominal pain and diarrhoea lasting several weeks. To confirm a diagnosis, tests and physical examinations will need to be carried out, these may include:

Blood and stool tests

A blood test can show whether you are experiencing internal inflammation and whether you are anaemic. In a similar way, your stools can be tested for any blood or signs of infection or inflammation. If any inflammation is discovered, you may have to undergo an endoscopy, scan or x-ray.


There are various types of endoscopy, all holding different names depending on the type of scope and where the examination is taking place. For example:

  • Upper gastrointestinal (GI) endoscopy (or gastroscopy) - This is to examine the upper part of your gut. A doctor will insert a thin, flexible tube with a camera down your throat so your oesophagus and stomach can be examined.
  • Colonoscopy or sigmoidoscopy - These are to examine symptoms of Crohn’s disease in the colon. A sigmoidoscope is a short tube that examines the rectum and lower part of the colon. A colonoscope is longer and more flexible, and looks at the whole of the large intestine, including the rectum and colon. Both are inserted through the anus.
  • Capsule endoscopy - This is not a tube, but a small capsule. You will be asked to swallow this grape-sized camera for a gut examination. The capsule contains a camera, light source and transmitter, it takes images of the gut and transmits them to a data recorder worn at the waist.

Barium x-ray

In this case, you may be offered a drink that contains barium sulphate - a harmless white substance that can coat the gut lining. It will make it clearer to see any stomach or intestine problems.

Symptoms of Crohn’s disease

The symptoms of Crohn’s disease vary depending on which part of the digestive system is affected, but abdominal pain and diarrhoea tend to be the most common side effects of the illness.

Abdominal pain typically results from the blockage of digestive food or faeces in the narrowed passages of the intestines due to inflammation of the lining. This often occurs between 30 and 60 minutes after eating - sometimes the blockage is very tight, causing excruciating pain. If a person is suffering from a severe blockage, they may experience a swollen abdomen and vomiting.

Other symptoms of Crohn’s disease can include:

  • night sweats
  • high temperature
  • unintended weight-loss
  • blood in mucus and/or faeces

Individuals may experience all or just a few symptoms of Crohn’s disease, and it's likely that there will be times when sufferers will experience none at all. Unfortunately, these ‘remission’ periods are often followed by a flare-up of symptoms.

What causes Crohn’s disease?

It's still not known what causes Crohn’s disease, although there are various factors thought to influence the development of the condition. Such factors include smoking, previous infection, genetics and environmental factors like lifestyle and diet.


People who smoke are twice as likely to develop Crohn’s compared to non-smokers. Smokers with the illness may also experience more severe symptoms.

Previous infection

In some cases, childhood infection can lead to abnormalities in the immune system. These abnormalities can result in the development of symptoms of Crohn’s disease.


According to the NHS, around three in 20 people with the condition have a family member also suffering. Research has identified more than 200 different genes that are more common in people with Crohn’s than the rest of the population. The prominence of the condition in some ethnic groups and not others also suggests a genetic link.

Immune system

A popular theory is that Crohn’s develops as a result of the immune system in the intestine reacting abnormally to the gut bacteria. In Crohn’s disease, a protein called TNF-alpha is released, disrupting the immune system. This protein destroys both the good and bad bacteria in the gut, resulting in inflammation.

Crohn’s treatment

As there is no cure, treatment for Crohn’s disease is essential for keeping symptoms under control and maintaining a remission period for as long as possible. Crohn’s treatment aims to reduce the inflammation in the intestine and to help manage the symptoms of Crohn’s disease, such as weight-loss and abdominal pain.


Individuals with moderate or severe symptoms of Crohn’s disease will typically receive steroid medication to reduce inflammation. Steroids can produce side effects, so the dosage may be reduced if and when symptoms start to improve.

In some cases, sufferers may experience a flare-up of symptoms over the course of steroid treatment or after the medication has been reduced. If this happens, extra medication may be needed to suppress the immune system.


An important part of Crohn’s treatment is surgery. According to Crohn's & Colitis UK, around one in five people with Crohn’s will need major surgery to remove part of their bowel in the first five years after diagnosis. Surgery for Crohn’s is designed to remove any blockages in the intestine caused by inflammation. Surgery is essential when badly affected parts of the intestine have caused abscesses and any other related problems.  

What is the best diet for Crohn’s disease?

While there is little research to support the notion that a change in diet or lifestyle can treat the symptoms of Crohn’s disease, there are some studies that suggest nutrition is important. As with any ongoing illness, it's vital to keep the body nourished.

Some patients undergoing treatment are advised to create a Crohn’s diet and make lifestyle changes to help reduce abdominal pain - especially if the inflammation has caused a narrowing of the intestines. In these cases, patients are recommended to reduce their fibre intake, avoiding indigestible foods and instead sticking to a ‘low residue’ Crohn’s diet.

The NHS suggests that individuals with Crohn’s disease find their symptoms are improved when eating six small meals a day, rather than three larger meals.

Specific carbohydrate diet (SCD)

This diet for Crohn’s disease has grown in popularity as a means of nutritional support. Avoiding specific carbohydrates such as starch and disaccharide (double) sugar molecules are the basic rules in this Crohn’s diet - these forms of carbohydrates are difficult for individuals with inflammatory bowel disease to digest.

This diet for Crohn’s disease may also eliminate grains due to their inflammatory potential on the gut wall.


Fibre, a type of carbohydrate found in plants, plays an important role in our diets. It encourages the growth of friendly bacteria, helping the digestive system to function smoothly and bulking up stools to help them pass through the gut. However, while the digestive system can break down soluble fibre, insoluble fibre is not so easily digested - this can cause bloating and sometimes abdominal pain.

Many people with Crohn’s are advised to be careful about the amount of insoluble fibre consumed within their Crohn’s diet to avoid symptom flare-ups. This is particularly important when there is evidence of narrowing or strictures. Foods high in insoluble fibre include:

  • nuts and seeds
  • brown rice
  • dried fruit
  • whole grain breads and cereals
  • beans and lentils
  • broccoli

Liquid diet

Alternatively, a specialised liquid formula diet (‘elemental’ or ‘polymeric’ diet) may be recommended to some patients as a diet for Crohn’s disease - this can help treat the condition when it has affected the small intestine. This type of Crohn’s diet is typically referred to as ‘nutritional therapy’. The liquid formula is made up of very small molecules that can be easily digested; it can help to improve nourishment while reducing inflammation and resting the bowel.

Food reintroduction diet

Many patients who are undertaking nutritional therapy - which usually lasts around two to eight weeks - will be encouraged to slowly reintroduce foods into their diet. This diet for Crohn’s disease helps individuals to pinpoint any foods that may be causing their symptoms to flare up. Examples of this Crohn’s diet can include the general elimination of foods and the LOFFLEX diet - the low fibre, fat limited, exclusion diet.

There is some evidence that following the LOFFLEX diet to identify foods that trigger symptoms and then sticking mainly to your list of 'safe' foods can help you stay in remission for longer. You should have regular reviews with your dietitian to make sure that all your nutritional needs continue to be met.

- Dr Stephanie Fade, PhD Dietitian

Natural remedies for Crohn’s

While there is no cure for Crohn’s disease, there are supplements and foods that are encouraged due to their tendency to reduce symptoms of Crohn’s disease. It's advised that you consult your doctor before introducing anything into your Crohn’s diet, as some of them may react with any medical treatment you are prescribed.

Below are some of the supplements believed to help ease Crohn’s symptoms:

Fish oil - This has been used to promote cholesterol health for a long time and it has suggested benefits for Crohn’s patients. According to the Cochrane Database of System Reviews, fish oil is rich in omega-3 fatty acids. Omega-3 fatty acids have anti-inflammatory properties; therefore, it's thought that introducing fish oil may help to reduce symptoms.

Probiotics - The gastrointestinal tract contains ‘good’ bacteria, these help digestion and offer protection against bad bacteria. When the body falls ill or has taken antibiotics, the body’s supply of good bacteria is reduced. Probiotics are recommended as they provide the gut with microorganisms that act similarly to the ‘good’ bacteria it requires.

Prebiotics - Prebiotics (indigestible carbohydrates) can be found in honey, whole grains, bananas, onions, garlic and artichoke. They are food for the intestinal bacteria - adding these to your diet for Crohn’s disease may improve the normal intestinal bacteria function.

Aloe Vera juice, chamomile and peppermint are also believed to help reduce Crohn’s symptoms, try adding them into your diet as a warm tea.

How can a nutrition professional help you?

During your diagnosis, a dietitian may have been part of your IBD team. They may have devised a diet plan for you to compensate for nutrient deficiencies and help manage your symptoms.

Following diagnosis, and in addition to medical support and advice from your GP and IBD team, you may find it beneficial to work with a nutrition professional. They can use their expert knowledge to design a personalised diet plan, tailored to your individual needs. They understand the importance of eating a balanced diet, and ensuring you achieve optimum health and well-being.

As symptoms of Crohn’s disease vary, receiving a specialised Crohn’s diet plan and personal advice can help you regain a sense of control over the condition. A suitably qualified nutrition professional will be able to guide and support you through the symptom remission periods and flare-ups, recommending what dietary changes can be made.

Furthermore, becoming educated in all things food may be able to help you to keep your symptoms at bay for the long term. Consulting a nutrition professional will also help alleviate some of the pressure and responsibility involved in monitoring what you eat.

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