New evidence suggests that the specific carbohydrate diet (SCD) can be an effective option on its own for inducing remissions in pediatric inflammatory bowel disease (IBD).
Dietary therapy for IBD has been entrenched since the introduction of the liquid exclusive enteral nutrition (EEN) decades ago. “EEN has been used with success for remission and mucosal healing for 50 or 60 years, and is still recommended by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition as primary therapy in newly diagnosed patients,” David L. Suskind, MD, director of Clinical Affairs and Quality Improvement and co-chair of the Nutrition Subcommittee of Seattle Children’s Hospital and the University of Washington, told MedPage Today.
The success of EEN led to experimentation using restricted whole-food diets for IBD in combination with drug therapy. In 2014, Stanley Cohen and colleagues reported clinical and mucosal improvement in a small series of children on SCD for 12 and 52 weeks while maintaining their prescribed medication.
In 2016, Suskind’s group published novel results on diet alone from an uncontrolled 12-patient (ages 10 to 17), two-site preliminary study. The results suggested that a 12-week trial of SCD without medication could induce remission in children with mild to moderate ulcerative colitis (UC) and Crohn’s disease (CD). To be eligible, patients could not have started a new IBD medication for at least a month before the study in the case of immunosuppressives and 60 days in the case of biologics.
This diet removes proinflammatory carbohydrates such as simple sugars and sweeteners (honey excepted), starches, grains, some legumes, and all dairy products other than hard cheese and yogurt fermented for 24 hours. The diet focuses instead on whole foods such as fresh vegetables, fruits, meats, fish, nuts, and certain oils, including olive and soy. Also excluded are processed foods, which can contain proinflammatory additives such as emulsifiers, thickeners, and stabilizers.
“At our IBD center we don’t actively suggest adding supplements of anti-inflammatory foods such as turmeric, fish oil, or sour cherry juice,” Suskind said. “We see good results without adding these, but I do encourage parents to buy organic produce if they can, to avoid possible pesticide residues.”
Assessed at 2, 4, 8, and 12 weeks, at study’s end the eight patients who completed the regimen achieved remission from SCD alone. At final follow-up, the mean pediatric CD disease activity index decreased from 28.1±8.8 to 4.6±10.3, while the mean UC disease activity index dropped from 28.3±23.1 to 6.7±11.6.
Two patients, however, failed to respond to the regimen, and two were unable to tolerate it. Three participants lost weight, which is always a concern in a growing child. But according to Suskind, most children eat well, gain appropriate weight, and grow normally, with Recommended Dietary Allowance intakes of micronutrients similar to those of the average American child. Evaluation for and, if necessary, supplementation with vitamin D and calcium are recommended.
In terms of laboratory inflammatory markers, the mean C-reactive protein level dropped from 24.1±22.3 to 7.1± 0.4 mg/L at 12 weeks in patients at one site and decreased from 20.7±10.9 to 4.8±4.5 mg/L at the other.
Pre-trial stool analysis had shown distinctive dysbiosis, with reduced microbial diversity in most patients’ microbiomes and a preponderance of organisms associated with inflammation. While no single inflammation-linked organism stood out, there was a major shift toward positive change in microbial composition suggestive of reduced inflammation and more normal composition. “But it’s difficult to define what is normal since everyone’s microbiome is different. Microbiomes are highly individual,” Suskind cautioned.
The SCD is now offered to all patients at Suskind’s center as part of standard care.
Previously, his group had published a small chart-review study of pediatric CD patients following the SCD and receiving no immunosuppression that suggested that this and other diets low in complex carbohydrates might be feasible therapeutic options for this population.
“Our research all began with simple observations and has continued to evolve,” said Suskind, whose group is currently recruiting for a double-blind study in Crohn’s disease to see if the SCD can be liberalized to include more foods, thereby making the diet more sustainable without diminishing its efficacy.
Meals will be provided to patients in three arms: the classic SCD, an altered version that incorporates oats and rice into prepared dishes, and a broader whole-food diet that allows all grains but corn and wheat and removes milk and food additives. The trial aims to enroll 21 CD patients by next year. “We want to know how we can make diet easier to follow on a day-to-day basis.”
Another benefit of dietary therapy, Suskind noted, is that many parents join their children in following the SCD, which is similar to the popular paleo diet, and while their children flourish, the parents lose weight.
“From our clinical experience with 400 children on dietary therapy and our research experience, we see that this diet works,” said Suskind, who is also planning a new multicenter study that aims to enroll 120 patients. “We are confident that dietary therapy will be a part of everybody’s treatment paradigm in the near future.”
While this treatment requires a shift in lifestyle, it empowers patients to play an active part in treatment, he added. “For this to work, education is very important, as well as having dietitians available, to ensure we take a holistic approach to patients’ healthcare.”