The indicator amino acid oxidation technique defined a protein requirement that is comparable with that estimated by the application of a biphase linear regression model to nitrogen balance data in the literature. Our data and the reanalysis of the preexisting nitrogen balance data suggest that the current recommended protein requirements are too low and require reassessment.

To our knowledge, this study was the first to directly estimate protein requirements in children by using stable isotopes and indicated that current recommendations are severely underestimated.