Plasma amino acid profile in obese children, adolescents, and adults: similarities or differences — a narrative review

Obesity, regardless of age, is associated with various metabolic disorders. Amino acids, as essential food ingredients, play a critical role in regulating glucose and energy metabolism. Thus, their plasma concentrations may reflect the metabolic state of the individual. This narrative review aims to find out similarities in plasma amino acid profiles across the selected obese individuals (children, adolescents, and adults). An analysis of 21 original studies revealed similar amino acid alterations regardless of the age group- in particular, elevated levels of branched-chain amino acids (BCAAs: isoleucine, leucine, valine), tyrosine, glutamic acid, alanine, and proline, as well as decreased concentrations of glutamine, serine, glycine, and asparagine. These findings suggest the presence of a common, age-independent metabolic signature of amino acids in obesity. Such changes may reflect impaired amino acid catabolism and have been linked to insulin resistance, increased risk of type 2 diabetes risk, and other metabolic complications. There is a need to establish age- and population-specific reference values for plasma amino acids to use amino acid profiling as a diagnostic and prognostic tool management of obesity. Accurate plasma amino acid profile measurements could support early detection of obesity-related metabolic disturbances and the implementation of targeted nutritional and therapeutic strategies.