Bile acids are
cholesterol-derived metabolites with a well-established role in the digestion and absorption of
dietary fat. More recently, the discovery of
bile acids as natural
ligands for the nuclear farnesoid X receptor (FXR) and membrane Takeda
G-protein-coupled receptor 5 (TGR5), and the recognition of the effects of FXR and TGR5 signaling have led to a paradigm shift in knowledge regarding
bile acid physiology and metabolic health.
Bile acids are now recognized as signaling molecules that orchestrate
blood glucose,
lipid and energy metabolism. Changes in FXR and/or TGR5 signaling modulates the secretion of
gastrointestinal hormones including
glucagon-like peptide-1 (GLP-1) and
peptide YY (PYY), hepatic gluconeogenesis,
glycogen synthesis, energy expenditure, and the composition of the gut microbiome. These effects may contribute to the metabolic benefits of
bile acid sequestrants,
metformin, and
bariatric surgery. This review focuses on the role of
bile acids in energy intake and
body weight, particularly their effects on
gastrointestinal hormone secretion, the changes in
obesity and T2D, and their potential relevance to the management of metabolic disorders.