A Pilot Randomized Control Trial to Assess the Adjunctive Effect of Diet on Response to Advanced Therapies in...

Diet may influence ulcerative colitis (UC), but its impact on medication response remains unclear. We examined whether two 5-day cycles of a low-calorie, plant-based (LC-PB), fasting-mimicking diet could improve UC response to medications in a controlled trial.

Adults with active UC starting advanced therapies were randomized to an LC-PB diet + therapy or a control diet + therapy. The LC-PB diet provided 1090 kcal on day 1 and 725 kcal on days 2-5. The Simple Clinical Colitis Activity Index (SCCAI) was assessed at baseline and week 8. The study, planned for 60 patients, ended early due to COVID-19. The primary endpoint was clinical response (week 8, SCCAI decrease ≥3). Secondary outcomes were clinical improvement (change in SCCAI from baseline), steroid tapering, C-reactive protein, serum amyloid A (SAA), and fecal calprotectin.

Of 32 enrolled patients, 23 completed the study. In the intention-to-treat analysis, 57% (n = 8 of 14) in the LC-PB arm achieved clinical response by week 8 vs 35% (n = 6 of 17) in control arm (P = .11). Secondary analyses indicated greater clinical improvement, measured as continuous SCCAI, in the LC-PB group compared with the control group (P = .039). The LC-PB group had better SCCAI subscores (ie, urgency, well-being), had reductions in SAA, and were tapered off steroids compared with the control group. Mean C-reactive protein and fecal calprotectin decreased more in the LC-PB group, but results were not significant. There were no serious adverse events relating to the diet and no weight loss.

The LC-PB diet did not improve clinical response to medications. However, it led to clinical improvement, steroid tapering, and reduced SAA. As results were limited by sample size, larger studies are needed.