Adult amino acid requirements: the case for a major revision in current recommendations.

This is a brief review about the current state of knowledge concerning the minimum physiological requirements for indispensable amino acids in healthy adult humans. It is hypothesized that current international estimations of these requirements are far too low, except for the sulfur-containing amino acids. Stable isotope tracer studies of amino acid kinetics are described, and that it is concluded that they support this hypothesis. Tentative revised estimates of requirements are presented.