By Chris Kresser, M.S.
Last updated on May 28, 2019

What Causes IBD?

Inflammatory bowel disease includes both ulcerative colitis (UC) and Crohn’s disease (CD). Like other autoimmune diseases, conventional therapies for IBD typically focus on suppressing the immune system. This has numerous unwanted side effects, including an increased risk for infection, and the efficacy of the drugs is quite variable.

As of 2015, 231 single nucleotide polymorphisms (SNPs) within 200 different genes are associated with IBD risk. Still, genetics only account for a small proportion of the variance in disease (8.2 percent for CD and 13.1 percent for UC) (1, 2). This means that environmental factors likely play a significant role. Factors implicated in IBD include gut dysbiosis, environmental toxins, and diet, among others.

The Standard American Diet has been associated with an increased risk of IBD, while anti-inflammatory diets have shown some promise for relief (3). Many patients with IBD have known food sensitivities (65 percent, 4), yet some patients may not know which foods might be harming them. I’ve discussed the limitations of food sensitivity testing previously on my podcast. This is where an elimination diet can be really helpful.

Enter the Paleo Autoimmune Protocol

The Paleo autoimmune protocol (AIP) is a Paleo-type diet, which removes grains, legumes, dairy, refined seed oils, and refined sugar, but also recommends initial removal of eggs, nightshades, coffee, alcohol, nuts, and seeds. The basic rationale is to avoid foods that might trigger intestinal inflammation or promote gut dysbiosis and immune dysregulation.

Like Paleo, AIP encourages consumption of nutrient-dense, healing foods, including bone broth, organ meats, and fermented foods. The elimination phase is typically followed by a maintenance phase until sufficient improvement in symptoms is achieved. At that point, select food groups can be carefully reintroduced. This allows patients to expand their diets, while identifying any foods that might be contributing to their symptoms.

I’ve mentioned before that the restrictions of AIP really aren’t based on any peer-reviewed evidence. While the study discussed today was not a randomized controlled trial, it certainly adds to the credibility of AIP, beyond just anecdotal support and my clinical experience with patients.

SAD to AIP in 6 Weeks

For the study, 15 patients were enrolled that had been living with IBD for an average of 19 years. A team including a nutritional therapist and registered dietitian led the participants through a six-week phased elimination program to transition from their current diet (SAD) to AIP. They remained on the full AIP diet for five weeks. Mayo score (a measure of ulcerative colitis activity) or Harvey-Bradshaw score (a measure of Crohn’s disease activity) was determined at baseline, after the six weeks of phased elimination, and at eleven weeks after a month on full AIP. Seven of the 15 patients were actively taking medications to help manage the symptoms of their disease during the intervention. Patients who were identified as deficient in vitamin D (three patients) or iron (six patients) were also started on nutritional supplements to correct these deficiencies.

Unexpectedly Effective

So, the results? The authors write:

Clinical remission was achieved by week 6 by 11/15 (73%) of study participants, and all 11 maintained clinical remission during the maintenance phase of the study.

Wow. Seventy-three percent of participants achieving clinical remission in six weeks rivals most drug therapies for inflammatory bowel disease, without any of the side effects. Let’s look at the breakdown by disease across the three timepoints.

Average Mayo score (disease activity) in ulcerative colitis patients:

Baseline: 5.8
Week six: 1.2
Week eleven: 1.0

Average Harvey-Bradshaw index (disease activity) in Crohn’s disease patients:

Baseline: 7.0
Week six: 3.6
Week eleven: 3.4

Additionally, four participants were able to discontinue some or all of their medications.

What It Means

This study suggests that the Paleo autoimmune protocol can be used as an effective treatment in many patients with IBD and that remission occurs quite rapidly. I’ve witnessed it quite often in the clinic, but I’m thrilled to see it documented in the literature as well!