What is Crohn’s Disease?

Crohn’s disease is a chronic inflammatory disease that can impact any area of the gastrointestinal tract from the mouth to the anus and commonly occurs in the ileum or colon. Areas of disease may be separated by segments of normal bowel. People with Crohn’s disease do not have a higher incidence of bowel cancers (unlike ulcerative colitis) than the general population.


What are the symptoms of Crohn’s disease?

Crohn’s disease is characterized by severe abdominal pain, frequent diarrhea, nausea, fever, and weight loss. The diagnosis is based on endoscopy, x-ray studies, and clinical signs. Some complications associated with it are fistulas, strictures, intestinal obstruction, and vitamin/mineral deficiencies.


What diet is recommended for Crohn’s disease?

Over the past few decades, medical treatment of Crohn’s disease has focused on ‘triple’ therapy (5-aminosalicylates

[5-ASA], corticosteroids, and azathioprine) and nutrition. Surgical resection of diseased bowel may also be recommended, but disease recurrence after surgery is still possible. The aim of supportive nutrition is to rest the bowel if desired (by Total Parenteral Nutrition [TPN] or elemental diets), to correct malnutrition and/or to manage the symptoms of Crohn’s disease.

For severe symptoms of Crohn’s disease, nutrition support is essential in preventing further muscle and protein losses, and in weight maintenance. Correcting common micronutrient deficiencies of calcium, folate, iron, zinc, vitamin D, and vitamin B12 may also be necessary1. In situations where bowel rest is needed or when enteral feeding is contraindicated (i.e. intestinal obstruction, some fistulas, etc.), TPN is justified. Enteral nutrition is otherwise the route of choice and has a primary role in the management of Crohn’s disease. Some studies have shown that enteral nutrition may promote remission in the acute phase of Crohn’s disease2, while others refute that. Elemental (predigested), semi-elemental, and polymeric diets were compared by meta-analyses and showed no difference in remission of Crohn’s disease, but use of corticosteroids successfully induced remission3.

There is some evidence that omega-3 fatty acids (i.e. fish oils) may be useful in reducing relapses in Crohn’s disease4,5 while routine glutamine supplementation6 and exclusion diets7 have shown limited benefit. Preliminary studies on probiotic preparations that contain Bifidobacterium, Lactobacillus, and Streptococcus show promise in preventing the recurrence of Crohn’s disease8,9.


Summary of Dietary Recommendations for Crohn’s Disease

  1. For active disease: TPN, enteral, or oral diets are used according to an individual’s tolerance and severity of his/her disease. Replacement of micronutrient deficiencies and correction of malnutrition are essential in recovery during any chronic illness, but some studies have shown that the chosen diet will not induce remission when compared with medication treatment. If a person is experiencing increased losses (due to diarrhea), malabsorption (due to ileal disease or resection causing a vitamin B12 deficiency) or anemia (low iron due to poor intake, malabsorption or bleeding), he/she may require long-term replacement of these micronutrients. Long term TPN or tube feeding may be a necessity to maintain adequate nutritional intake for some people with Crohn’s disease.
  2. For inactive disease: Exclusion diets have shown little benefit in preventing recurrence of Crohn’s disease but some individuals may need to limit certain fibres (i.e. if frequent diarrhea, strictures), lactose (if lactose intolerant), or other foods according to tolerance. A balanced diet of adequate protein, fat, and carbohydrate is generally recommended. Because of possible micronutrient deficiencies, a multivitamin/mineral supplement is recommended for all people with Crohn’s disease.
  3. Omega-3 fatty acids (fish oils) have been promoted for treatment of Inflammatory Bowel Disease (IBD) because of their anti-inflammatory effect. One study using 2.7 grams of enteric-coated omega-3 fatty acids showed a remission in 59% of patients with Crohn’s disease compared with 26% in the placebo group. Contact your physician before initiating use of these products.
  4. Because intestinal microflora may be important in IBD, use of prebiotics, probiotics, and antibiotics are of growing interest.
    Prebiotics (non-digestible foods that stimulate bacterial activity in the colon) include psyllium, inulin, oligofructose, lactosucrose and germinated barley foodstuff (GBF)9.
    Probiotics (living microorganisms) include Lactobacillus, Bifidobacterium, Streptococcus thermo-philus and Saccharomyces boulardii. While probiotics are considered safe and well-tolerated, poor labelling and quality control are an issue. Talk to your doctor or dietitian if you are interested in any of these products.

Mary Flesher, Clinical Dietitian, The Richmond Hospital
First published in the Inside Tract® newsletter issue 137 – May/June 2003
1. Goh, J. and O’Morain, C.A. (2003). Review article: Nutrition and adult inflammatory bowel disease. Aliment Pharmacology and Therapeutics, 17(3):307-320.
2. Lochs, H. et al (1991). Comparison of enteral nutrition and drug treatment in active Crohn’s disease. Gastroenterology, 101:881-888.
3. Gilandi, D. and Allgaier, H.P. (2002). Diet therapy in chronic inflammatory bowel disease: Results from meta-analysis and randomized controlled trials. Schweiz Rundsch Med Prax, 91(47): 2041-2049.
4. Belluzi, A. et al (1994). Effects of new fish oil derivatives on fatty acid phospholipid-membrane pattern in a group of Crohn’s disease patients. Digestive Diseases and Sciences, 39:2589-2594.
5. Belluzi, A. et al (1996). Effect of en enteric-coated fish-oil preparation on relapses in Crohn’s disease. New England Journal of Medicine, 334:1557-1560.
6. Den, H.E. et al (1999). Effect of long-term oral glutamine supplements on small intestinal permeability in patients with Crohn’s disease. Journal of Perenteral and Enteral Nutrition, 23:7-11.
7. Pearson, M. et al (1993). Food intolerance and Crohn’s disease. Gut, 34:783-787.
8. Madsen, K.L (2001). The use of probiotics in gastrointestinal disease. Canadian Journal of Gastroenterology, 15(12): 817-822.
9. Kanauchi, O. et al (2003). Anti-TNF therapy for Crohn’s disease. Current Pharmaceutical Design, 9(4): 289-294.