What Does The Research Show?

Study Design

The first study to evaluate the effects of i3.1 was a randomized, double-blind, placebo-controlled intervention clinical trial with three parallel arms. A total of 84 patients (53 female, 31 male; age range 20-70 years) with IBS and diarrhoea according to the Rome-III criteria were randomly allocated to receive one capsule a day for 6 weeks containing either: (1) i.31 high dose; (2) i.31 low dose; and (3) placebo. At baseline, and 3 and 6 weeks of treatment, patients filled the IBS-related quality of life (IBS-QoL), Visceral Sensitivity Index (VSI), and global symptom relief questionnaires.


The high dose contained 1-3 x 1010 cfus/capsule and the low dose contained 3-6 x 109 cfus/capsule (Lorenzo-Zúñiga, 2014).


IBS-related quality of life (IBS-QoL)


Scores of IBS-QoL were standardized to a 0-100 scale. Improvement was calculated as the difference between the midpoint (day 21) or endpoint (day 42) scores and the baseline score for each group.


At week 3, there was a statistically significant improvement in IBS-QoL in both treatment groups when compared to the placebo group and this was statistically different at both week 3 and 6. Differences among groups became even more significant after six weeks of supplementation, without statistical differences between the high and the low probiotic doses.

Main Findings

IBS-QoL improvement compared to baseline after 42 days of treatment. Global scores improved significantly more in both treatment groups compared to the placebo.


Graph 1. Shows the IBS related quality of life score improvement compared to baseline after 42d of treatment

Per domain analysis (Emotional Health, Mental Health, Sleep Energy, Physical Functioning, Diet, Social Role, Physical Role and Sex) showed a greater improvement in almost all the domains in the patients treated with the probiotic combination (both high and low doses) than in those treated with a placebo and this difference reached statistical significance in the Mental Health domain.


When the individual response to treatment was analysed, the number of patients with a good response to the treatment (defined as score improvement ≥ 15 points), was significantly larger in those treated with probiotics (both with the high and low dose) than in those treated with placebo.