Inflammatory Bowel Diseases (IBDs), including Crohn’s disease and ulcerative colitis, affect about 1.6 million Americans.
IBDs are complex gastrointestinal disorders that arise due to genetic predisposition, T-cell dysregulation, gut imbalance, environmental exposure, and dietary factors.
Conventional medical therapy for IBD focus on suppressing the immune system, yet response rates continue to remain suboptimal. It is for this reason that we need to study dietary factors not only to help improve response to conventional treatment but to also potentially be used as primary therapy or maintenance therapy for patients with IBD.
A Western diet – high in refined carbohydrates, omega-6 fatty acids, and saturated fat while low in fiber, vitamins, and generally nutrient dense foods – is associated with an increased risk of IBD. Recent data suggests that a semi-vegetarian diet (allowing milk and eggs, fish once per week, other meat once every 2 weeks), specific carbohydrate diet (removal of all grains, most dairy, sweeteners except for honey), or anti-inflammatory diet (modified carbohydrate and fatty acid intake, increased prebiotic/probiotic ingestion) can be associated with improved rates of achieving or maintaining clinical response.
The autoimmune protocol (AIP) diet is an extension of the Paleo diet. The AIP diet focuses on an initial elimination phase of foods including grains, legumes, nightshades, dairy, eggs, coffee, alcohol, nuts and seeds, refined/processed sugars, oils, and food additives including certain medications (e.g. NSAIDs). Consumption of fresh, nutrient dense foods, bone broth, and fermented foods is emphasized and sleep/sleep hygiene, stress management, support systems, and physical activity are also addressed.
The rational behind the elimination phase is to avoid substances that could potentially trigger intestinal inflammation, dysbiosis, and/or symptomatic food intolerance.
This is then followed by a maintenance phase until the person achieves a measurable improvement in symptoms and overall well-being. Reintroduction of food groups is then initiated gradually so that foods or food groups that may contribute to symptoms can be identified while liberalizing dietary restrictions.
Eligible adult patients with either symptomatic Crohn’s disease (CD) or ulcerative colitis (UC) were allowed to participate.
The AIP dietary intervention consisted of a 6-week elimination phase followed by a 5-week maintenance phase. Reintroduction was not formally studied although guidance was provided at the end of the study. A health coach and registered dietitian were included to help guide and counsel participants.
Endoscopy, radiology, and/or biomarker assessment were performed at baseline and at study completion to assess for mucosal healing. Dietary intake data and quality of life assessment data was also collected.
Fifteen participants completed the study. The average participants was female, 44 years of age, never used tobacco, and had been diagnosed with IBD for 19 years. Medication use varied from NSAIDs, immunomodulators, biologicals, and systemic steroids.
Clinical remission was achieved at week 6 by 73% of participants and all of those maintained remission during the maintenance phase of the study.
Quality of life assessment scores (using the Short Inflammatory Bowel Disease Questionnaire, SIBDQ) improved from 46.5 at baseline to 53.3 at week 6 and 60.5 at week 11.
No statistically significant differences were observed for hemoglobin, hematocrit, C-reactive protein, albumin, transaminases, bilirubin, creatinine, total cholesterol, HDL, LDL, triglycerides, or fecal calprotectin. There was also no significant change in body weight.
Achievement of clinical remission did not differ significantly between CD and UC participants.
Increasing evidence suggests that dietary modification can modulate inflammation and improve clinical responses in IBD.
Results of this study support the use of dietary modification as an adjunct to IBD therapy, even among those with moderate-to-severe disease.
However, individual consideration should be given to anatomical variation and requires counseling and close follow-up, as was shown with 2 participants with CD with ileal strictures developing worsening disease activity or partial small bowel obstruction due in part to the prescribed dietary changes.
The premise of the AIP diet involves a staged eliminated of foods that may be associated with immune stimulation and intolerance, maintenance of the eliminated foods, followed by staged reintroduction of certain foods over time.
Although not formally studied, stress has been associated with IBD flares and low physical activity or nighttime sleep with risk of IBD, so addressing these factors seemed logical.
Dietary changes can be an important adjunct to IBD therapy not only to achieve remission but perhaps improve the durability of response and remission. For a subset of patients, dietary and lifestyle modification alone may be sufficient to control underlying inflammation.