Amino Acids

, Volume 37, Issue 1, pp 1–17

Amino acids: metabolism, functions, and nutrition

Review Article

DOI: 10.1007/s00726-009-0269-0

Cite this article as:
Wu, G. Amino Acids (2009) 37: 1. doi:10.1007/s00726-009-0269-0


Recent years have witnessed the discovery that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. Additionally, AA are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of AA and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the functions. However, elevated levels of AA and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among AA in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional AA, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these AA may be beneficial for (1) ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaning-associated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility); (2) optimizing efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, AA have important functions in both nutrition and health.


Amino acids Health Metabolism Nutrition 



Amino acids


Branched-chain amino acids


Nutritionally essential amino acids


Eukaryotic translation initiation factor


Mammalian target of rapamycin


Nutritionally non-essential amino acids


Nitric oxide


Portal-drained viscera

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Animal Science, Faculty of NutritionTexas A&M UniversityCollege StationUSA

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