Results Summary

What was the research about?

People with Crohn’s disease have ongoing stomach pain, cramping, and diarrhea. A person’s diet can affect symptoms. But questions remain about which diets help the most to reduce symptoms.

In this study, the research team compared the effects of two diets on symptoms and quality of life in patients with Crohn’s disease:

  • The Mediterranean diet, or MD allows many types of foods, but limits the amount eaten. It’s high in fresh fruits, vegetables, nuts, fish, whole grains, and olive oil and limits red meat and processed foods.
  • The Specific Carbohydrate Diet, or SCD lists foods that are and aren’t allowed. It allows fruits, vegetables, unprocessed meats, and some lactose-free dairy, but doesn’t allow some sugars and starches like potatoes or yams.

What were the results?

At six weeks, 64 percent of patients on the MD and 68 percent on the SCD had stayed on the diet. At 12 weeks, 42 percent on the MD and 40 percent on the SCD had stayed on the diet.

The two diets didn’t differ in how they affected patients’ health after 6 and 12 weeks. At six weeks, about 45 percent of patients on each diet reported feeling better and no longer had symptoms of diarrhea and stomach pain. Overall, patients on each diet reported improved quality of life and less pain, fatigue, sleep disturbance, and feelings of isolation from family and friends at six weeks.

Who was in the study?

The study included 191 people with Crohn’s disease from across the United States. All had mild to moderate symptoms. Of these, 91 percent were White, 4 percent were Black, 1 percent were Asian, and 4 percent reported other, more than one, or didn’t report a race; 4 percent were Hispanic. The average age was 40, and 63 percent were women.

What did the research team do?

The research team assigned patients by chance to either the MD or SCD. Every week for six weeks, patients had three prepared meals and two snacks per day delivered to their homes. After six weeks, patients could either pay for the prepared meals or continue the diet on their own. The study website had support for meal planning. A dietician was available to answer questions.

Patients completed surveys at the start of the study and 6 and 12 weeks later. Patients reported their symptoms online each day and how much they stayed on their assigned diet at weeks 3, 6, 9, and 12.

Patients, doctors, and staff from the Crohn’s & Colitis Foundation helped to plan and conduct the study.

What were the limits of the study?

Providing meals for the first six weeks of the study may have helped patients stay on the diet. Results may differ in real-word settings. Most patients were White; results may differ for patients of other backgrounds.

Future research could compare the MD and SCD diets with other diets.

How can people use the results?

Patients with Crohn’s disease and their doctors can use the results when considering diets to decrease symptoms.

How this project fits under PCORI’s Research Priorities
IBD Partners formerly was a Network Partner in PCORnet®, the National Patient-Centered Clinical Research Network. PCORnet® has been developed with funding from the Patient-Centered Outcomes Research Institute (PCORI).

Final Research Report

This project's final research report is expected to be available by October 2022.

Peer-Review Summary

The Peer-Review Summary for this project will be posted here soon.

Conflict of Interest Disclosures

Project Information

James D. Lewis, MD, MS
Crohn's and Colitis Foundation of America, Inc.

Key Dates

40 months
March 2016
January 2022

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Last updated: November 15, 2021