Popular IBD Diet Associated With Increased Microbial Diversity

San Diego—The specific carbohydrate diet (SCD), popular among patients with inflammatory bowel disease (IBD), is associated with distinct changes in the intestinal microbiome, researchers at Rush University have found.

The trademarked SCD, as described by Elaine Gottschall, MSc, in her book, “Breaking the Vicious Cycle” (The Kirkton Press; 2012), is “predicated on the understanding that ulcerative colitis, Crohn’s disease, irritable bowel syndrome and gluten therapy resistant celiac [disease] are the consequence of an overgrowth and imbalance of intestinal microbial flora.”

Ece Mutlu, MD, associate professor of medicine, Rush University Medical Center, Chicago, and her colleagues analyzed fecal samples from 20 patients with IBD who reported following the SCD and 20 patients with IBD who did not adhere to the diet: Each group included 10 patients with Crohn’s disease and 10 patients with ulcerative colitis. Some patients were receiving immunosuppressant medications at the time of fecal sample analysis.

Dr. Mutlu and her team performed 16S rDNA pyrosequencing and found that individuals in the SCD group had greater intestinal bacterial diversity compared with those in the control group, in addition to having a differing microbiome composition. The study was not designed to measure endoscopic and clinical disease activity, but Dr. Mutlu told Gastroenterology & Endoscopy Newsthat she observed symptom relief in some patients following the diet.

“I have observed that a small number of my own IBD patients drastically improved on the SCD and achieved complete long-term mucosal healing, or were able to reduce or discontinue immunosuppressants for several years.”

These anecdotal observations and the findings from the study justify further investigation of the diet’s effect, said Dr. Mutlu, who presented the study at the American College of Gastroenterology 2013 Annual Scientific Meeting (poster 1619).

“A longitudinal study following IBD patients before the start of the diet, and during and after the SCD, would have been much harder for us to complete, but I think this should be done going forward and it could help us learn a lot more in the future.”