Gut Microbiota Alteration After Long-Term Consumption of Probiotics in the Elderly

Gut microbiota has been proven to be of crucial importance in maintaining human health. However, the microbiota profile changes with aging, while the loss of microbiota diversity and the alterations in the optimal composition and quantity of beneficial microbes are believed to increase the risk of many diseases. Although the short-term modulatory impact of probiotics on gut microbiota has been revealed in various studies, no studies focused on longer time consumption of probiotics have been demonstrated. In this study, we found that microbial diversity in the probiotic group was similar to that in the control. We identified a panel of microbiota changes, such as Blautia (10.24 vs. 3.76%, P = 0.006), Streptococcus (7.38 vs. 1.16%, P = 0.004), and Enterococcus (0.13 vs. 0.00%, P = 0.030) were more abundant in the probiotic group. Faecalibacterium, a genus containing anti-inflammatory property, also had a higher abundance in the probiotic group in the gut. The microbiota architecture in the different probiotic dose groups was also revealed. No statistical difference was observed in regard to the short-chain fatty acid concentration between the groups. High-dose intake of probiotics resulted in lower microbial richness. The profile of inflammatory factors indicated that only the level of IL-1β was higher in the probiotic population. Taken together, our study demonstrated that the long-time intake of probiotics caused significant changes in the gut microbiota structure, including an increase in the composition of beneficial microorganisms, which might contribute to the maintenance of host health and homeostasis of microenvironment. More prospective cohorts were needed to illustrate the influences of probiotics on the gut microbiota.