Efficacy and safety of a food supplement with standardized menthol, limonene, and gingerol content in patients with irritable bowel syndrome: a double-blind, randomized, placebo-controlled trial

Background: Irritable bowel syndrome (IBS), which negatively affects the quality of life of patients and places considerable financial burdens on healthcare systems, has a current worldwide prevalence of 11.2%. Most medications for treating IBS, including spasmolytics, laxatives, and antidiarrheals, have low efficacy. Therefore, effective and safe new approaches to IBS treatment are necessary.Purpose: This study assessed the efficacy and safety of a food supplement, which contained standardized menthol, limonene, and gingerol, in patients with IBS or IBS/functional dyspepsia (FD).Design: A double-blind, randomized, placebo-controlled trialMethods: Fifty-six patients with IBS or IBS/FD were randomly assigned to the intervention group (Group 1) or control group (Group 2), which were given supplement or placebo in addition to the standard treatment regimen for 30 days, respectively. Three outpatient visits were conducted during the study. Symptom severity was tested with a 7x7 questionnaire at each visit. Qualitative and quantitative composition of the intestinal microbiota were assessed at several visits based on 16S rRNA gene sequencing data.Results: At Visit 1, median total 7x7 questionnaire score was in the moderately ill range for both groups, with no statistically significant difference between the groups (p = 0.1). At Visit 2, total 7x7 score decreased to mildly ill, with no significant difference between the groups (p = 0.4). The total 7x7 questionnaire score was significantly lower in Group 1 (borderline ill) than in Group 2 (mildly ill) at Visit 3 (p = 0.02). The numbers of short-chain fatty acid-producing bacteria and bacteria involved in fatty acid biosynthesis increased significantly in Group 1 compared with those in Group 2 patients.Conclusion: The food supplement with standardized menthol, limonene, and gingerol content increased the efficacy of standard therapy in IBS and FD patients.