Gut microbiota-bone axis

ABSTRACT

The gut microbiota (GM) is an important regulator of body homeostasis, including intestinal and extra-intestinal effects. This review focuses on the GM-bone axis, which we define as the effect of the gut-associated microbial community or the molecules they synthesize, on bone health. While research in this field is limited, findings from preclinical studies support that gut microbes positively impact bone mineral density and strength parameters. Moreover, administration of beneficial bacteria (probiotics) in preclinical models has demonstrated higher bone mineralization and greater bone strength. The preferential bacterial genus that has shown these beneficial effects in bone is Lactobacillus and thus lactobacilli are among the best candidates for future clinical intervention trials. However, their effectiveness is dependent on stage of development, as early life constitutes an important time for impacting bone health, perhaps via modulation of the GM. In addition, sex-specific difference also impacts the efficacy of the probiotics. Although auspicious, many questions regarding the GM-bone axis require consideration of potential mechanisms; sex-specific efficacy; effective dose of probiotics; and timing and duration of treatment.

KEYWORDS:

• Development
• aging
• bone mineral density
• bone structure
• probiotics

Acknowledgments

C. Villa holds a Banting and Best Diabetes Centre-Novo Nordisk Studentship. E. Comelli holds the Lawson Family Chair in Microbiome Nutrition Research at the University of Toronto and W. Ward holds a Canada Research Chair in Bone and Muscle Development at Brock University.

Funding

E. Comelli and W. Ward acknowledge that funding provided through NSERC, a Collaborative Research and Development Grant from the Dairy Research Cluster Initiative (Dairy Farmers of Canada, Agriculture and Agri-Food Canada, Canadian Dairy Commission), and the Centrum Foundation Research Innovation Fund and the Department of Nutritional Sciences at the University of Toronto, has allowed them to pursue this research area.

Conflict of interest

Authors declare no conflict of interest.