Gut microbial metabolite short-chain fatty acids and obesity

Over the past decade, the gut microbiota has emerged as an essential mediator in the pathophysiology of obesity and related metabolic disorders. In this context, the reciprocal interactions of the gut microbiota structure and their metabolite profiles with host metabolism predisposing to a range of pathological conditions (e.g., insulin resistance) related to energy homeostasis have been increasingly discussed in various animal models and human cohorts. Remarkably, as the role of gut microbial metabolites as critical signaling molecules that function through the complementary host receptors has come to be appreciated, tremendous attention has been focused on the proposed diet-gut microbiota-host homeostasis axis, entailing extensive cross-disciplinary efforts in medical, pharmaceutical, and agricultural sciences. This review will discuss the recent advances in understanding the mechanisms whereby the gut microbiota modulates the effects of diet and shapes the host metabolism either towards or away from obesity and related metabolic conditions. In particular, the interactions of short chain fatty acids (SCFAs), a subset of key gut microbial metabolites, with their specific receptors will be reviewed in relation to host energy homeostatic regulation and evaluated for potential as novel therapeutic targets for diet-induced obesity.