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

BACKGROUND & AIMS: 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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.