Effects of Saccharomyces cerevisiae CNCM I-3856 and vitamin K2 on the gut microbiota of patients with osteoporosis and healthy controls using in vitro short-term colonic simulations

The gut microbiome may be involved in bone health through the gut-bone axis. Saccharomyces cerevisiae CNCM I-3856 benefits gut health in patients with irritable bowel syndrome, which is more prevalent in women and may be associated with higher osteoporosis prevalence. We evaluated the effects of S. cerevisiae CNCM I-3856 ± vitamin K2 (K2) on the gut microbiota of patients with osteoporosis and healthy controls. Short-term in vitro colonic fermentations were performed using feces from healthy and osteoporosis-diagnosed individuals ( n = 12/cohort). Three conditions were tested: untreated, probiotic, probiotic+K2. Colonic supernatants (48 h) were evaluated for microbial metabolic and community profile. While there was a distinct separation of the microbial community composition between the donor cohorts, S. cerevisiae CNCM I-3856 ± K2 induced significantly higher acetate, propionate, butyrate, and lactate production versus untreated control for both cohorts ( p = 0.003 to <0.001). S. cerevisiae CNCM I-3856 ± K2 supplementation generally reduced bacterial alpha-diversity and beta-diversity analysis revealed a distinct separation between the S. cerevisiae CNCM I-3856 ± K2 samples and the untreated samples for both cohorts. There were statistically significant changes in 11 taxa with S. cerevisiae CNCM I-3856 ± K2 supplementation (healthy, n = 4; osteoporosis, n = 6; both, n = 1). Metabolomic fingerprinting demonstrated significant differences in metabolic profile between the S. cerevisiae CNCM I-3856-supplemented samples and the untreated control. Overall, it could be concluded that a single administration of S. cerevisiae CNCM I-3856 enhanced microbial function through SCFA-mediated species and pathways in both a healthy population and osteoporosis patients, suggesting a potential for bone health through the gut-bone axis.