Effects of probiotics on bone mineral density and bone turnover: A systematic review

Probiotic supplements have been shown to improve bone health in animal models, although it remains uncertain whether these beneficial effects extend to humans. We undertook a systematic review of the literature to determine the effects of probiotic interventions on skeletal outcomes in postmenopausal women. MEDLINE, EMBASE, CENTRAL, and the Cochrane Database of Systematic Reviews were searched from inception to October 2020 for controlled trials comparing the effects of probiotic-containing supplements with placebo on bone mineral density (BMD) or bone turnover markers. Risk of bias was assessed using the Cochrane Risk of Bias 2 Tool. Of 338 records identified, six randomized, placebo-controlled trials (n = 632) were eligible for inclusion. All studies assessed postmenopausal women for durations of 6-12 months; three were considered to be at high risk of bias. Four studies examined Lactobacillus-containing probiotics, one assessed a proprietary blend of lactic acid bacteria, and one evaluated Bacillus subtilis. Effects of probiotic interventions on BMD were inconsistent, with the majority of studies demonstrating no benefit at the spine or hip. Probiotic effects on bone turnover markers were similarly heterogeneous. High quality studies are needed to determine whether probiotic interventions have a role in maintaining bone health in humans.