Dietary protein and bone health: Roles of amino acid-sensing receptors in the control of calcium metabolism and bone homeostasis

In this article, we review the evidence that dietary protein has a positive influence on bone health, reduces hip fracture risk, and promotes post-fracture recovery, and we consider the molecular, cellular, and endocrine bases of the interactions that link protein and calcium metabolism, including effects via IGF-1 and PTH. In addition, we consider the roles of amino acid-sensing mechanisms in coupling dietary protein intake to metabolic change as well as the central role of calcium-sensing receptors (CaRs) in the control of calcium metabolism. Finally, we consider how recently identified broad-spectrum amino acid-sensing receptors from class 3 of the G-protein coupled receptor superfamily including, remarkably, the CaR itself may contribute to the impact of dietary protein on bone.