The Specific Carbohydrate Diet Is Not Superior to a Mediterranean Diet in Improving Crohn’s Disease-Associated Symptoms, Fecal Calprotectin, or C-Reactive Protein Levels

The Specific Carbohydrate Diet (SCD) described by Elaine Gottschall in her book “Breaking the Vicious Cycle” emphasizes fresh fruits, nonstarchy vegetables, and unprocessed meats but excludes grains and most dairy. It is a popular therapeutic diet among patients, but its efficacy in ameliorating Crohn’s disease-related symptoms and inflammation is unknown. 

A large multicenter trial aimed to evaluate the effectiveness of the SCD compared to the Mediterranean diet (MD) in inducing clinical response, decreasing stool calprotectin by >50% and <250 μg/g, and decreasing high-sensitivity C-reactive protein (hsCRP) by >50% and <5 mg/L. The study enrolled 194 adult patients with mildly to moderately active Crohn’s disease with short Crohn’s Disease Activity Index (sCDAI) scores >175 and <400. Any concomitant Crohn’s disease medication therapy was allowed as long the dosage and frequency did not change before enrollment and during the study. At baseline, 57% of participants were taking a biologic medication, and 47% had inflammation, indicated by hsCRP, calprotectin, or colonoscopy.

For the first 6 weeks, patients were instructed to consume only centrally prepared meals and snacks according to their assigned diet and to log daily symptoms and dietary adherence. At 6 weeks, data analyzed from 191 patients of both arms showed significant improvements in sCDAI, CDAI, and short Inflammatory Bowel Disease Questionnaire scores, as well as fatigue, sleep, pain, and social isolation (P<.02 for all outcomes). The proportion of patients achieving remission (46.5% on the SCD and 43.5% on the MD), >50% decrease in the fecal calprotectin level (34.8% with SCD and 30.8% with MD), and CRP response (only in 5.4% with SCD and 3.6% with MD) were similar in both arms.