Efficacy of Single-Strain Probiotics Versus Multi-Strain Mixtures: Systematic Review of Strain and Disease Specificity

The diversity of probiotic products makes choosing an appropriate probiotic challenging. One unanswered question is whether single-strain probiotics are more effective than multi-strain mixtures. The aim of this review is to account for both disease and strain specificity to determine whether single strains or multiple strains are equivalent or more effective. This literature review of randomized controlled trials from 1973 to 2019 was used to compare the pooled efficacy of trials with a single strain versus the probiotic mixture with same matched strain within the same type of disease indication. A total of 65 RCTs were included (41 with single strains, 22 multi-strain mixtures and 2 comparing single strain to mixture arms) for eight different disease indications (N = 10,863). Only three strains (L. rhamnosusGG,L. helveticusR52 andB. lactisBb12) had corresponding trials with matching mixtures. Use ofL. rhamnosusGG only was significantly more protective for necrotizing enterocolitis compared to two mixtures also containing different strains ofB. lactis. The mixture ofL.rhamnosusGG andB. lactisBb12 was significantly more effective thanL. rhamnosusGG alone for the eradication ofH. pylori. In most cases, single strains were equivalent to mixtures. Choice of an appropriate probiotic should be based, not on the number of strains in the product, rather based on evidence-based trials of efficacy. In most cases, multi-strain mixtures were not significantly more effective than single-strain probiotics.

Automated summary

The diversity of probiotic products makes choosing the right probiotic challenging. Research shows that in most cases, single-strain probiotics are as effective as multi-strain mixtures. The choice of probiotic should be based on evidence of efficacy rather than the number of strains in the product.