Digestive Enzyme Formulation Intervention in Irritable Bowel Syndrome Patients Who Previously Clinically Responded to Mediterranean Low FODMAP Diet: A Single-Arm Clinical Trial

IBS patients who participated in a two-arm clinical trial (ClinicalTrials.gov ID: NCT03997708) and responded to the Mediterranean Diet Adjusted Low FODMAP (MED-LFD) Diet will be considered eligible if their symptoms recurred one year after their initial response to the dietary intervention. Among them, patients without any or mild symptoms, defined as IBS severity scoring system (IBS-SSS) ≤ 175, will be excluded. Moreover, subjects who were randomized to the MED-LFD arm in the previous study, but could not adhere to the dietary intervention, will be included too.

A jar containing the digestive enzymes in the form of powder will be provided to each patient at the start of the study. Patients will be instructed to use the powder formulation according to manufacturer instructions for 1 month. To assess compliance, the weight of each jar will be measured both at the initiation and the end of the study. Patients will also be asked on three different days (one day from the weekend), to estimate the average number of meals per day. Due to the limited sample size (54 patients who received the MED-LFD diet in the previous phase will be screened for eligibility), a control group will be omitted. To reduce the placebo effect, patients will be misinformed that half will take a placebo formulation, randomly.

All patients will be thoroughly trained regarding the proper consumption of the powder (exact dose, timing, etc.), through personal training, videos, leaflets, and other type of training materials.