Introduction to the 5th Amino Acid Assessment Workshop.

Amino acids (AAs) may be consumed at intakes above those that could be obtained from the normal diet, to promote health status in certain specific situations (e.g., sports training, aging). In this context, the relevant AAs may be used at high intake levels, which may in turn trigger adverse effects. There is little information on the adverse effects or pathophysiological consequences of excessive intakes of individual amino acids or mixtures. Hence, a series of workshops (named AAAW) are being organized to bring together experts in the fields of amino acid metabolism and nutritional effects, cell and molecular biology, toxicology, and regulatory issues and policy, with the aim of establishing a paradigm for the characterization of risks associated with specific intakes of amino acids by humans. The first 3 workshops covered general aspects concerning AAs (functions, risk characterization, differences in subpopulations, definition of surrogate markers, etc.). The fourth AAAW focused on branched-chain AAs. The articles in this supplement issue of the journal summarize the fifth workshop in the series, which focused on sulfur amino acids.