Advances in diet and IBD: Crohn’s Disease

Advances in diet and IBD: Crohn’s Disease

With the increasing industrialisation and westernisation of diet, the incidence of Crohn’s Disease (CD) is increasing2,4. It’s well recognised that the inflammation in Crohn’s Disease may be driven by dietary components1.

Diet and IBD

Studies have demonstrated that 70-90% of CD paediatric patients will achieve remission when using Exclusive Enteral Nutrition (EEN)2,3,4,5. This indicates that diet can have a large impact on IBD, however adherence is key.

Exclusive Enteral Nutrition is where a patient receives all their dietary requirements, including vitamins and minerals, from a liquid nutritional formula. This may be done for 6-8 weeks, depending on the patient.

As well as helping achieve remission, it can also assist with mucosal healing, weight gain, improved vitamin D, improved bone health and better quality of life. It may also be effective in resolving inflammatory strictures and enterocutaneous fistulae3.

Existing diet strategies for IBD

There are currently a few other strategies for controlling IBD using diet.

Low residue diet

A low residue diet limits fibre intake. Often people who are newly diagnosed with self-limit high fibre foods to control loose bowel actions and abdominal pain. However there is only a small evidence base that this works, and is mostly indicated in structuring disease only.

Generally, it is advisable to continue to consume fibre to tolerance. This can help improve bowel health, avoid constipation and encourage a more diverse gut microbiome.

Low FODMAP diet

FODMAPs are fermentable carbohydrates, and includes foods like dairy, wheat, beans and lentils, and some fruits and vegetables. The low FODMAP diet is based on foods such as eggs and meat, non-dairy milks such as almond milk, grains like rice, quinoa and oats and a limited selection of fruits and vegetables.

The low FODAMP diet is used in patients with IBD, generally because many patients have coexisting IBS (60% in CD and 39% in Ulcerative Colitis)6,7. Even when IBD is in remission, these patients complain of wind and bloating. The low FODMAP diet can be used only when IBD is in remission to help with these symptoms; however there is no evidence for it inducing remission.

Mediterranean Diet

The Mediterranean Diet is characterised by lots of vegetables, fruits and wholegrains, olive oil as the primary source of fats, protein from fish, legumes and nuts/seeds, with minimal red meat and no sugary drinks or processed foods.

It is well established in its use for other inflammatory diseases such as cardiovascular disease, Alzheimer’s disease and rheumatoid arthritis. This is because plasma levels of inflammatory markers such as C-Reactive Protein (CRP) and TNFα are reduced. As well as this, there is a lower incidence of IBD in Southern Europe, where there is a higher consumption of a Mediterranean Diet.

In 2020, Hamed Khalili et al published a paper titled ‘Adherence to a Mediterranean diet is associated with a lower risk of later-onset Crohn’s disease: results from two large prospective cohort studies’. The study looked at over 80,000 participants over 17 years. There was a significant lower risk of later-onset CD, however there was no indication of that for Ulcerative Colitis.

A new option: Crohn’s Disease Exclusion Diet (CDED) and Partial Enteral Nutrition (PEN)

There was a need for an alternative therapy without the side effects of current medications. While EEN has shown to induce remission of CD, it is difficult for adults to adhere to and sustain in the longer term.

A number of papers have been published on the Crohn’s Disease Exclusion Diet (CDED) with Partial Enteral Nutrition (PEN)2,5,9. Partial Enteral Nutrition uses liquid nutritional formula, but only for a portion of a patient’s dietary needs. This means there is no need for a naso-enteric tube, and it is much more palatable and sustainable then EEN.

These studies all found:

  • 60-70% of patients achieved remission (depending on the study)
  • A reduction in the mean CD Activity Index and Harvey-Bradshaw Index
  • Normalisation of C-Reactive Protein (CRP) in 70% of patients or reduction in mean CRP

The paper by Levine A et al, ‘Crohn’s disease exclusion diet plus partial enteral nutrition induces sustained remission in a randomized controlled trial’ is of particular interest. It compared the use of CDED & PEN (starting at 50%, reducing to 25% at 6 weeks) to EEN for 6 weeks followed by PEN (25%) with a free diet for the remaining 6 weeks.

While both induced remission, CDED & PEN did so at a higher rate (75%) than EEN (59%) although this didn’t reach statistical significance. This may be because 97% of participants tolerated CDED & PEN compared to only 73% of EEN.

At the end of 12 weeks, 76% of the patients on CDED & PEN were in remission, compared to only 45% using PEN & free diet. It showed that the absence of proinflammatory foods seems critical in sustaining remission.

What is the Crohn’s Disease Exclusion Diet (CDED)2,5

The CDED can be used for both adults and children with active CD (both ileal and colonic). It can also help patients that are failing biologic therapies despite dose escalation.

It is based on whole foods, removing foods hypothesised to be inflammatory. The inflammatory foods are thought to negatively affect the microbiome, intestinal barrier and intestinal immunity.

The following foods are excluded:

  • Animal fats (saturated)
  • Dairy
  • Gluten
  • Carrogeenans (Gelling/thickening/stabilizing properties, found in dairy products, processed deli meat)
  • Maltodextrins (cereals, powdered drinks, baked goods, sauces/dressings, sweets, low fat products, thickener in foods)
  • Emulsifiers (dairy, sauces, spreads, low fat products, processed goods)
  • Taurine (organ meats, fish)
  • Sulfites (dried fruit, wine, vinegars, processed fruit and veg, fruit and veg juices)

The diet is split into 3 phases: phase 1 (induction of remission), phase 2 (consolidation) and phase 3 (maintenance).

Phase 1 of CDED

Phase 1 mandatory foods (per day):

  • 2 medium potatoes: peeled, cooked and cooled
  • 2 bananas
  • 1 apple, peeled
  • 150-200g chicken breast (low taurine)
  • 2 eggs (low taurine)

Phase 1 allowed foods:

  • 100-150g lean white fish (1/7)
  • White rice, rice noodles, rice flour
  • Fruit: 1 avocado, 5 strawberries, rockmelon
  • Approx 3 serves
  • Veg: 2 tomatoes, 2 cucumbers, 1 carrot, fresh spinach (1 cup), 3 lettuce leaves
  • Approx 5-6 + serves
  • Condiments: olive/canola oil, pure spices, fresh herbs, onion, garlic, ginger, lemon, honey, table sugar
  • Beverages: water, herbal teas, 1 glass of freshly squeezed orange juice daily

The dietitian will work with you to determine your dietary needs, and supplement your food with liquid formula (currently Fortisip). For everything else, if it’s not on the list it doesn’t exist (including coffee and alcohol).

Phase 2 of CDED

As well as the foods from phase 1, you can add:

  • Protein: extra can of tuna weekly (olive oil), 200g lean red meat weekly only if desired
  • Carbs: ½ sweet potato, 1 slice of wheat bread, ½ cup legumes (dry), quinoa, ½ cup oats
  • Greater variety of fruit and veg
  • Unsalted nuts/seeds

Phase 3 of CDED (maintenance phase)

As well as all the foods from phase 1 and 2, you can add:

  • Other parts of chicken (no skin/organs)
  • Full fat yoghurt
  • 2 slices of wheat bread or pasta
  • All fruits (sulfite free)
  • All vegetables (except celery and kale)

Phase 3 also allows 2 days of ‘free meals’ (up to 2 per day), where a greater variety in protein and carbohydrates are permitted. Ideally these should be cooked at home. It’s important to have the 2 days consecutively, as it was found to be more effective at maintaining remission, compared to small but frequent exposure to inflammatory foods.

It’s important to undertake these dietary changes with support from your gastroenterologist and dietitian. However dietary changes such as these generally do no harm so it’s worth giving it a go.

Our gastroenterologists and dietitian are all trained in alternative options to IBD such as the Crohn’s Disease Exclusion Diet so make an appointment today.


  1. Levine A et al. A case-based approach to new directions in dietary therapy of Crohn’s disease: Food for thought. Nutrients 2020,12,880
  2. Levine A et al. Crohn’s disease exclusion diet plus partial enteral nutrition induces sustained remission in a randomized controlled trial. Gastroenterology 2019, 157:440-450
  3. Liu J et al. Benefits of exclusive enteral nutrition in Adults with complex active Crohn’s disease: a case series of 13 consecutive patients. Crohn’s & Colitis November 2019, 360, 1(3): 1-7
  4. Levine A and Wine E. Effects of enteral nutrition on Crohn’s disease: clues to the impact of diet on disease pathogenesis. Inflammatory Bowel Disease May 2013, 19 (6):1322-1329
  5. Sigall-Boneh R et al. Diet therapy with the Crohn’s disease exclusion diet is a successful strategy for induction of remission in children and adults failing biological therapy. Journal of Crohn’s and Colitis 2017, 1205-1212
  6. Quigley E. Overlapping irritable bowel syndrome and inflammatory bowel disease: less to this than meets the eye. Therapeutic Advances in Gastroenterology 2016, 9(2):199-212
  7. Weimers P and Burisch J. The importance of detecting irritable bowel-like symptoms in inflammatory bowel disease patients. Journal of Crohn’s and Colitis 2018: 385-386
  8. Khalili H et al. Adherence to a Mediterranean diet is associated with a lower risk of later-onset Crohn’s disease: results from two large prospective cohort studies. Gut 2020, 69:1637-1644
  9. Sigall-Boneh R et al. Partial enteral nutrition with a Crohn’s disease exclusion diet is effective for induction of remission in children and young adults with Crohn’s disease. Inflammatory Bowel Disease 2014, 20(8): 1353-1360


Contributed by Jenny Carney