A Randomized Trial Comparing the Specific Carbohydrate Diet to a Mediterranean Diet in Adults With Crohn's Disease

Gastroenterology. 2021 Sep;161(3):837-852.e9. doi: 10.1053/j.gastro.2021.05.047. Epub 2021 May 27.


Background & aims: This study compared the effectiveness of the Specific Carbohydrate Diet (SCD) to the Mediterranean diet (MD) as treatment for Crohn's disease (CD) with mild to moderate symptoms.

Methods: Adult patients with CD and with mild-to-moderate symptoms were randomly assigned 1:1 to consume the MD or SCD for 12 weeks. For the first 6 weeks, participants received prepared meals and snacks according to their assigned diet. After 6 weeks, participants were instructed to follow the diet independently. The primary outcome was symptomatic remission at week 6. Key secondary outcomes at week 6 included fecal calprotectin (FC) response (FC <250 μg/g and reduction by >50% among those with baseline FC >250 μg/g) and C-reactive protein (CRP) response (high-sensitivity CRP <5 mg/L and >50% reduction from baseline among those with high-sensitivity CRP >5 mg/L).

Results: The study randomized 194 patients, and 191 were included in the efficacy analyses. The percentage of participants who achieved symptomatic remission at week 6 was not superior with the SCD (SCD, 46.5%; MD, 43.5%; P = .77). FC response was achieved in 8 of 23 participants (34.8%) with the SCD and in 4 of 13 participants (30.8%) with the MD (P = .83). CRP response was achieved in 2 of 37 participants (5.4%) with the SCD and in 1 of 28 participants (3.6%) with the MD (P = .68).

Conclusions: The SCD was not superior to the MD to achieve symptomatic remission, FC response, and CRP response. CRP response was uncommon. Given these results, the greater ease of following the MD and other health benefits associated with the MD, the MD may be preferred to the SCD for most patients with CD with mild to moderate symptoms. ClinicalTrials.gov Identifier: NCT03058679.

Keywords: Clinical Trial; Comparative Effectiveness; Mediterranean Diet; Nutrition; Randomization.

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biomarkers / blood
  • C-Reactive Protein / metabolism
  • Comparative Effectiveness Research
  • Crohn Disease / blood
  • Crohn Disease / diagnosis
  • Crohn Disease / diet therapy*
  • Crohn Disease / microbiology
  • Diet, Mediterranean* / adverse effects
  • Dietary Carbohydrates / administration & dosage*
  • Dietary Carbohydrates / adverse effects
  • Feces / chemistry
  • Feces / microbiology
  • Female
  • Gastrointestinal Microbiome
  • Humans
  • Inflammation Mediators / blood
  • Leukocyte L1 Antigen Complex / metabolism
  • Male
  • Middle Aged
  • Remission Induction
  • Severity of Illness Index
  • Time Factors
  • Treatment Outcome
  • United States


  • Biomarkers
  • Dietary Carbohydrates
  • Inflammation Mediators
  • Leukocyte L1 Antigen Complex
  • C-Reactive Protein

Associated data

  • ClinicalTrials.gov/NCT03058679