GAA consumption via diet
Guanidinoacetic acid (GAA; also known as glycocyamine) is a natural amino acid-like derivative of glycine and L-arginine. GAA plays several metabolic roles in the human body, with creatine synthesis being recognized as a crucial pathway of GAA utilization. A daily output of GAA largely depends on endogenous synthesis that occurs mainly in the kidney and pancreas, while diet has traditionally been considered as an irrelevant source of GAA in humans. However, several common foods can contain GAA (see: https://foodb.ca/compounds/FDB005417), suggesting that exogenous supplies may contribute to a total GAA out-turn; no studies so far provided data about dietary GAA exposure in the general public. Given a fundamental role of creatine in human nutrition and energy metabolism, accounting for food-driven GAA might add up to a well-balanced creatine homeostatic load. In this cross-sectional study, we aimed to quantify the amount of GAA consumed through the regular diet in the US adult population, using open-source data from the 2017–2018 National Health and Nutrition Examination Survey (NHANES).