A Pilot Randomized Control Trial to Assess the Adjunctive Effect of Diet on Response to Advanced Therapies in Patients With Ulcerative Colitis

Adults with active ulcerative colitis who were starting advanced drug therapies were randomly assigned to a low-calorie, plant-based, fasting-mimicking diet alongside their therapy or to a control diet alongside their therapy. The diet arm received two 5-day cycles providing 1090 kcal on day 1 and 725 kcal on days 2 to 5. Disease activity was scored at baseline and at week 8 with the Simple Clinical Colitis Activity Index. The trial was planned for 60 patients and ended early because of COVID-19, with 32 patients enrolled and 23 completing.

The authors reported that the primary endpoint was not met. Clinical response at week 8 was reached by 57% of the diet arm and 35% of the control arm, a difference that did not reach statistical significance. In secondary analyses the authors reported greater improvement in the continuous disease activity score in the diet arm, better urgency and well-being subscores, reductions in serum amyloid A, and more steroid tapering. They reported that mean C-reactive protein and fecal calprotectin fell further in the diet arm but that those results were not significant. They reported no serious adverse events related to the diet and no weight loss.

This is a pilot trial that stopped at roughly half its planned size, and its primary outcome showed no significant difference between the diets. The supporting findings are secondary outcomes from a small sample, which the authors say limits the results. Participants were patients with active ulcerative colitis starting advanced drug therapy, not a general wellness population. The intervention was an investigator-described low-calorie plant-based regimen, and the study does not evaluate Prolon directly.