Crohn's Disease (CD) is a chronic, relapsing-remitting, inflammatory bowel disease, that can affect the entire gastro-intestinal (GI) tract lining from mouth to rectum, in any age group.
Symptoms can impact everyday life and be debilitating. They include; fever, abdominal pain, diarrhoea, fatigue, weight loss, nausea, bloating, bleeding, anaemia & malnutrition. Symptoms can also present outside of the GI tract in the skin, joints or even the eyes. CD lesions are recognised as patchy ulcerations. Over-time, complications such as fistulas, strictures or abscesses may develop, causing severe damage to the GI tract, sometimes requiring medical surgery.
There is currently no cure for CD, medical treatment options include immunosuppressive medications. These treatments aim to dampen immune over-activity, chronic inflammation and prolong clinical remission, but they have multiple side effects.
Industrialised countries experienced a steady rise of CD after world war II. CD continues to rise in developed countries more than in developing countries. Japan, China, and India have seen an increase since the western lifestyle was adopted.
What causes Crohn's Disease?
Although the exact cause is still unknown, CD is considered a multifactorial disease. Genetics, environmental factors, gut microbiota, the intestinal barrier and a dysregulated immune system interplay, causing disease onset and development.
Genetics - Genome wide association studies identify 37 alleles specific to CD. Genes associated include; ATG16L1, NOD2, MUC2 and IL23R. However, only approx. 13% of CD is known to be genetic, suggesting a role for environmental factors.
Environmental factors -
The inflammatory 'western diet' (eg animal fat, sugar, artificial sweeteners, emulsifiers, additives, wheat proteins, low-fibre, low fruit & veg and high salt). Food allergens such as dairy are common in CD.
Cigarette smoking (including early life exposure and passive smoking) causes a two fold increase in the risk for CD.
Virus, bacterial and fungal infections.
Vitamin D deficiency.
Childhood antibiotic exposure.
Other medications include; oral contraceptives, aspirin, and non-steroidal anti-inflammatory drugs.
The three most important lifestyle activities that effect CD include; lack of sleep, high stress and a sedentary lifestyle, which exacerbate inflammation.
Intestinal barrier permeability - environmental factors can cause damage to the tight junctions of the intestinal barrier over time. This damage to the barrier allows microorganisms, food and toxins to leak through and be exposed to immune cells that guard the gut lining. This initiates a cascade of pro-inflammatory cytokines (TNFa, INFg, IL17) and immune cells causing inflammation of the gut lining.
Gut microbiota - CD patients have reduced diversity in gut microbiota compared with healthy individuals. Dysbiosis is when the complex ecosystem of the microbiome becomes imbalanced with overgrowth of harmful micro-organisms such as yeast and bacteria. If there is also intestinal permeability, these harmful organisms pass through the barrier and are exposed to the immune cells lining the gut, initiating immune chaos! The micro-organisms Escherichia coli and the fungi; Candida tropicalis and Malassezia have been studied in CD.
Nutritional Therapy in CD
There is a growing interest in nutrition as a critical factor for CD treatment. While current medical therapies aim to reduce inflammation and calm down the immune system, nutritional therapies can take a whole person approach and fix the root cause. This involves correcting dysbiosis, managing inflammation, limiting luminal antigen exposure, healing the intestinal barrier, improving nutrient deficiencies and balancing the gut microbiome.
Specialised Diets to Manage Crohn’s Disease
Below are a selection of diet plans that have been studied for CD:
Enteral diets: (or special pre-formulated liquid diets) are recommended by the European Crohn’s and Colitis Organisation and by the guidelines of the European Society of Clinical Nutrition and Metabolism. Used for malnourished patients undergoing GI surgery.
The Specific Carbohydrate Diet: eliminates complex carbohydrates, processed foods, most dairy products, and common food additives. Studies show this diet can improve symptoms and patient quality of life, and in some cases maintained remission.
FODMAP diet: excludes short-chain carbohydrates (eg some fruits, onions, garlic, beans, lentils, and legumes), which are poorly absorbed and highly fermented by intestinal bacteria. This diet improves GI symptoms (eg diarrhoea, bloating and pain) but there is no evidence of improvement of inflammation.
The Autoimmune protocol diet: eliminates grains, legumes, nightshade vegetables, dairy, eggs, coffee, alcohol, nuts/seeds, processed sugars, oils. Aims to eliminate allergens and irritants to calm the Autoimmune process, particularly useful if multiple Autoimmune conditions are present.
Semi-Vegetarian Diet: strongly limits meat and fish, without eliminating them. Based on vegetable, fruits, cereals, eggs, yoghurt, and milk, while excluding all processed and refined foods. This diet has been effective in preventing CD relapses in some studies.
Personalised Nutritional Therapy
As with all Autoimmune conditions, nutritional therapy that is personalised to an individual's specific needs, will be more beneficial than following a general restrictive diet. Crohn's patients will react differently to different food groups. Keeping a food or symptoms diary may help monitor reactions to certain food groups.
Working with a professional Nutritional Therapist can be extremely beneficial in CD not only to identify and eliminate problem foods or microbes, but also to carefully introduce the correct nutrients to heal the GI tract. Some suggestions that may be useful include:
eliminate inflammatory foods (eg sugar, red meat, trans fats, processed & fried foods)
eliminate potential food allergens (eg gluten, dairy, soy, nuts, corn, yeast etc)
reduce 'FODMAP' or wind producing foods to help with GI symptoms
minimise gut irritants (eg alcohol, caffeine, citrus, smoking etc)
eliminate artificial sweeteners, emulsifiers and additives (eg maltodextrin, sucralose)
reduce harsh fibres (eg grains, bran, raw fruits & veg)
minimise sulphur containing foods (eg eggs, garlic, onion, dried fruits, brassica)
identify and eliminate potential harmful gut microbes (eg - anti fungal protocol)
address nutrient deficiencies with liquid complexes (eg vitamin D, multivitamins & minerals)
increase soups, vegetable smoothies, protein shakes
eat well-cooked, easy to digest vegetables, to rebalance the microbiome
increase polyphenols which have an anti-inflammatory effect (eg curcumin, green tea)
increase essential fatty acids (eg liquid fish oil) to reduce inflammation
repair and heal the intestinal barrier (eg bone broth, glutamine etc)
increase prebiotic foods to grow a healthy microbiome (eg asparagus, bananas, oats)
take probiotics (eg lactobacillus plantarum) or probiotic foods if tolerated (eg kimchi)
eat small meals regularly to reduce stress load on the GI and chew food until liquid
Drink water and herbal teas (especially if you are losing fluid due to diarrhoea)
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