Protein requirements in humans.

The general principles underlying protein requirements are outlined and daily allowances for protein are derived appropriate to the various age and sex population subgroups of the United States. Median body weights are however used for all age groups of the population rather than the desirable body weights used previously for adults. Following the recommendations of the FAO/WHO/UNU international working group, the protein requirement for male and female adults was taken as 0.6 g.kg-1.d-1 of high-quality highly digestible protein. By use of an age-specific scoring system and the mean amino acid composition and digestibility of the US diet, this allowance became 0.83 g.kg-1.d-1 of mixed US dietary protein--a value similar to the previous RDA but derived in a different manner. Tabulated daily protein allowance data are presented for reference age and sex groups for the US population (child-adult) together with the additional needs of pregnancy and lactation.