For patients with mild or remitted ulcerative colitis, a catered, low-fat, high-fiber diet improved quality of life and stool markers of dysbiosis and inflammation, according to the findings of a small crossover trial.
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Patients with inflammatory bowel disease often ask what they should eat, but few studies have addressed that question, Julia Fritsch, of the University of Miami and her associates wrote in Clinical Gastroenterology and Hepatology. Building on previous findings that a high-fat diet may contribute to inflammatory bowel disease, they randomly assigned 38 adults whose ulcerative colitis was in remission or mild (with a flare within the past 18 months) to receive either a low-fat diet (with 10% of daily calories from fat and high amounts of fruit and vegetables) or an “improved American standard diet” (with 35%-40% of daily calories from fat but more fruit and vegetables than Americans typically eat). Each diet was catered, delivered to patients’ homes, and lasted 4 weeks, followed by a 2-week washout period, after which each participant switched to the other diet.
Of the 38 patients, 17 completed the study. Food recall surveys over 24 hours showed that both diets were healthier than what participants ate at baseline, and daily web-based food diaries (such as www.nutrihand.com/Static/index.html) confirmed that more than 94% of patients adhered to the amount of fat in each diet. Even though participants in both groups ate only about half of the provided fruits and vegetables, the primary outcome of quality of life based on the short inflammatory bowel disease questionnaire (SIBDQ) significantly improved from a median of 4.98 (interquartile range, 4.1-6.0) at baseline to 5.77 (IQR, 5-6.4) with the low-fat diet and 5.55 (IQR, 4.75-6.25) with the improved American standard diet. Both diets also produced significant improvements in quality of life as measured by the 36-Item Short Form Survey and in disease activity as measured by the partial Mayo score.
Notably, however, only the low-fat diet significantly reduced serum amyloid A, which is a marker of mucosal inflammation, and intestinal dysbiosis, which was quantified by 16S RNA ribosomal sequencing. “Of note, there were several variables that were associated with changes in the microbiota composition,” the researchers wrote. These included the SIBDQ, C-reactive protein, interleukin-6, interleukin-1 beta, and 32 dietary components such as protein, potassium, iron, and zinc.
“These data suggest that even patients in remission [from ulcerative colitis] could benefit from a healthier diet,” the investigators concluded. “Just as importantly, neither diet exacerbated symptoms, which is notable given the higher fiber in both catered diets.” They called catering “a feasible way to perform a diet intervention study with high adherence,” noting that “catering a diet for a patient with IBD for a year costs between $19,000 and $21,000 per patient. The cost of a patient on a biologic such as ustekinumab is approximately $130,752 to $261,504.”
The study was supported by the Crohn’s and Colitis Foundation Broad Medical Research Program, Micky and Madeleine Arison Family Foundation Crohn’s and Colitis Discovery Laboratory, and the Martin Kalser Chair. The senior author disclosed ties to Boehringer Ingelheim, Gilead, AbbVie, Seres Therapeutics, Shire, Landos, Pfizer, and several other pharmaceutical companies. The other researchers reported having no conflicts of interest.