The purpose of this review is to examine the anorexia nervosa-microbiota-bone relationship, offering a compilation of the relevant human and animal studies that may contribute to a more comprehensive understanding of potential mechanisms involved.

Recent studies have implicated fermentation by-products of the gut microbiota in bone metabolism.

Compromised bone health often accompanies anorexia nervosa due to energy deficiency and hypoestrogenism. The gut microbiome has been implicated as a link between these conditions and impaired bone growth phenotypes. Current research supports decrements in Firmicutes and short-chain fatty acids with increases in Methanobrevibacter smithii and Proteobacteria in anorexia nervosa. A potential mechanism for microbiome-regulated bone growth is through modulation of insulin-like growth factor-1. Future research should aim to examine short-chain fatty acids, probiotics, and prebiotics as alternative therapies to treat low bone density in anorexia nervosa.