Gut & MicrobiomeHow Gut Bacteria Metabolites Determine Whether Exercise and Diet Reverse Bone Loss in Older Adults
As we age, the gut microbiome shifts in ways that tip bone metabolism toward resorption and fracture risk. This narrative review of 56 studies synthesizes how gut microbial metabolites — particularly short-chain fatty acids, lipopolysaccharide, TMAO, and bile acids — connect age-related gut dysbiosis to osteoporosis. Crucially, the authors propose that baseline gut microbiome status may explain why some older adults respond well to exercise and dietary interventions for bone health while others do not. They outline a precision rehabilitation framework in which microbiome profiling sorts patients into 'sensitive' and 'resistant' groups, with resistant individuals receiving adjunctive probiotic or synbiotic therapy. Fecal SCFA-to-calprotectin ratio is proposed as a candidate stratification biomarker, though prospective clinical validation is still needed.
