Supplementation of a single species probiotic does not affect diversity and composition of the healthy adult gastrointestinal microbiome

Abstract

Over several years, consumer probiotic consumption has increased substantially. Consequently, the number of over-the-counter probiotic products available to consumers has also increased. Many consumers use probiotics for preventative purposes rather than to treat specific illnesses. The influence of probiotics on the healthy human gut microbiome has not been extensively studied and many questions remain regarding the influence of probiotic supplementation on existing gut flora. In this study, the effect of a commercial probiotic containing Bifidobacterium infantis on the composition and diversity of gut flora in healthy adults was examined. Thirty participants were enrolled in the study and randomly assigned to probiotic (n = 15) or placebo (n = 15) groups. Over the course of the study, three stool samples were collected to facilitate baseline, probiotic/placebo effect, and return to baseline measurements. The probiotic/placebo effect samples were collected after taking a probiotic/placebo tablet daily for 30 days, and the return to baseline sample was collected 30 days after completing the treatment course. V3/V4 16S rRNA sequencing was performed on all samples and data was analyzed using QIIME. No significant difference in gut community diversity or composition between probiotic and placebo groups was observed. This finding suggests that use of a single species probiotic in healthy individuals does not significantly influence microbial gastrointestinal diversity.