Dietary geraniol ameliorates intestinal dysbiosis and relieves symptoms in irritable bowel syndrome patients: a double-blind randomized clinical trial

Geraniol is an acyclic monoterpene alcohol with well-known anti-inflammatory and antimicrobial properties which demonstrated eubiotic activity in the gut microbiota in patients with irritable bowel syndrome (IBS). BIOintestil is a food supplement combining Palmrose essential oil high geraniol and ginger root. To evaluate symptoms improvements and microbiota modulation in patients with IBS treated with BIOintestil compared to placebo. This double-blind, placebo-controlled, randomized multicenter trial included IBS (Rome III) patients (1:1) assigned to either BIOintestil or placebo, once daily for 4 weeks. Fifty-6 IBS patients were included. Patients treated with BIOintestil showed a significant reduction in IBS symptoms severity score (IBS-SSS) compared to placebo (IBS-SSS score 195 vs 265, p=0.001). The rate of responders according to IBS-SSS score (reduction>50 points) was significantly higher in BIOintestil 52% vs placebo 16.7% group, mainly due to IBS mixed subtype (BIOintestil 53.9% vs placebo 7.7%, p=0.011). Adverse events were comparable between the treatment groups. There were significant differences in microbiota composition after BIOintestil administration, in particular, Erysipelotrichaceae family, Clostridiaceae (p=0.1) and another genus of Ruminococcaceae, Oscillospira (p=0.01) tended to decrease while Ruminococcaceae, specifically Faecalibacterium (p=0.09) trended to increase in the BIO-intestil group. The analysis of the main circulating proinflammatory cytokines and chemokines showed no differences between the placebo and the BIOintestil at baseline and follow-up. BIOintestil is effective in treating overall IBS symptoms, together with an amelioration of gut microbiota profile in terms of increased proportions of health-associated microorganisms and reduced amounts of potential pathobionts.