Fig. 1

SCFAs produced by gut microbiota facilitate bone health. SCFAs can reduce intestinal pH and promote calcium absorption. In terms of immunity, SCFAs induce Th differentiation into CTLs and Tregs and regulate serotonin content through Th, which directly or indirectly promotes bone formation and inhibits bone resorption. Furthermore, SCFAs regulate Tregs by inhibiting HDAC and activate osteogenic differentiation and osteoclast differentiation-related genes to control bone metabolism. SCFAs also promote the differentiation and activity of osteoblasts and inhibit the activity of osteoclasts to some extent, thus facilitating the calcification and deposition of bones and reducing the risk of bone loss (e.g., estrogen deficiency). Meanwhile, it can suppress the secretion of inflammatory mediators, which is beneficial to bone health