Efficacy of i3.1 Probiotic on Improvement of Lactose Intolerance Symptoms: A Randomized, Placebo-controlled Clinical Trial.

GOAL: The aim of this study was to assess the efficacy of probiotic i3.1 in improving lactose intolerance symptoms compared with placebo after 8 weeks of treatment. BACKGROUND: Probiotics are promising strategies to prevent and improve lactose intolerance symptoms, but previous studies have provided conflicting results. MATERIALS AND METHODS: This randomized, prospective, placebo-controlled study was conducted at the Hospital Juárez de México. We recruited adult patients with lactose intolerance confirmed by a lactose hydrogen breath test (LHBT) ≥20 parts per million (ppm) and a lactose intolerance symptom score ≥6 both upon lactose challenge. We compared the change from baseline in the scores of a validated symptom questionnaire and the LHBT after 8 weeks of probiotic or placebo treatment. RESULTS: We included 48 patients: 33 receiving the probiotic and 15 receiving placebo (2:1 randomization). Demographic characteristics were homogeneous between groups. The reduction in total symptom score after a lactose challenge was significantly higher in the probiotic group versus the placebo group (-5.11 vs. -1.00; P<0.001). All the subscores significantly decreased from baseline in the probiotic group, except for vomiting, with significant differences between the probiotic and placebo groups for abdominal pain (P=0.045) and flatulence (P=0.004). The area under the curve of the LHBT was significantly reduced from baseline in the probiotic group (P=0.019), but differences between groups were not significant (P=0.621). Adverse events were mild without differences between groups, and no serious adverse event was registered. CONCLUSION: The i3.1 probiotic was safe and efficacious in reducing lactose intolerance symptoms in patients with lactose intolerance, but did not change the LHBT.