Title -- Copyright -- Contents -- 1. Introduction -- References -- 2. Conceptual framework for estimating protein and amino acid requirements -- 2.1 Basic concepts -- 2.1.1 Metabolic demand -- 2.1.2 Growth -- 2.2 Dietary influences on demand -- 2.2.1 Energy -- 2.2.2 Micronutrients -- 2.2.3 Lifestyle and environmental influences -- 2.3 Achieving nitrogen balance -- 2.3.1 Maintenance amino acid catabolism and obligatory nitrogen losses -- 2.3.2 Digestibility of dietary proteins -- 2.3.3 Protein quality: matching the supply to the demand -- 2.3.4 Protein utilization and nitrogen balance -- 2.4 Response to variation in protein intake -- 2.4.1 Changes in body composition -- 2.4.2 Labile protein reserves -- 2.4.3 Protein turnover and amino acid recycling -- 2.5 Definition of requirement -- 2.6 Adaptive mechanisms -- 2.6.1 Adaptation of amino acid oxidation -- 2.6.2 Adaptation of urea metabolism: nitrogen metabolism in the lower gut -- 2.7 Summary metabolic model -- References -- 3. Statistical concepts and procedures involved in deriving recommendations for protein and amino acid requirements -- 3.1 Overview -- 3.2 Phases of requirement estimation -- 3.2.1 Gathering and screening the data -- 3.2.2 Estimating the requirements of individuals -- 3.2.3 Examining influential factors -- 3.2.4 Estimating the distribution of requirements within a population -- 3.3 Reference requirements and intakes -- 3.3.1 Reference intakes and risk of dietary inadequacy for individuals -- 3.3.2 Reference intakes and risk of dietary inadequacy for a population -- 3.4 The cost of protein deficiency -- References -- 4. General methods used for determining protein and amino acid requirements -- 4.1 Nitrogen balance -- 4.1.1 Practical aspects -- 4.1.2 Data interpretation -- 4.1.3 Other factors -- 4.1.4 General conclusion on nitrogen balance -- 4.2 Carbon balance.

4.2.1 Practical aspects -- 4.2.2 Specific protocols -- 4.2.3 The 24-hour protocol -- 4.2.4 The fed-only protocol -- 4.2.5 Short-term fasting/feeding protocol -- 4.2.6 Data interpretation -- 4.2.7 General conclusion on carbon balance method -- 4.3 Indicator amino acid method -- 4.3.1 General approach -- 4.3.2 Summary of indicator amino acid method -- 4.4 Predictions from the obligatory nitrogen loss -- 4.5 Indirect estimates through measurement of protein utilization -- 4.6 Conclusions -- References -- 5. Protein-energy interactions -- 5.1 Energy intakes and protein requirements -- 5.1.1 Nitrogen retention and variable energy balance -- 5.1.2 Nitrogen retention and variable energy turnover -- 5.1.3 Energy intakes and the interpretation of requirement studies -- 5.1.4 Protein-energy interactions in children -- 5.1.5 Protein-sparing effect of non-protein energy substrates -- 5.2 The protein:energy ratio -- 5.2.1 Protein:energy ratios as a measure of dietary protein quality -- 5.2.2 Protein:energy ratio of requirements and dietary assessment -- 5.2.3 Derivation of reference protein:energy ratios -- References -- 6. Protein quality evaluation -- 6.1 Prediction of protein quality using the protein digestibility corrected amino acid score (PDCAAS) approach -- 6.1.1 Protein digestibility -- 6.1.2 Biological value -- 6.1.3 Amino acid score -- 6.2 Current concerns about the protein digestibility corrected amino acid score (PDCAAS) approach -- 6.3 Conclusions -- References -- 7. Protein requirements of adults, including older people, and women during pregnancy and lactation -- 7.1 Evaluation of published nitrogen balance studies -- 7.1.1 Adjustment for dermal and miscellaneous nitrogen losses -- 7.1.2 Statistical analysis of nitrogen balance data -- 7.2 Population distribution of protein requirement and determination of the median.

7.3 Estimation of the variability and population reference intakes -- 7.4 Basal metabolic demands: the obligatory nitrogen loss -- 7.5 Potentially important influential factors identified in the meta-analysis -- 7.5.1 Dietary source of protein -- 7.5.2 Climate -- 7.5.3 Age -- 7.5.4 Sex -- 7.6 Comparison with previous reports and other information -- 7.6.1 Dietary source of protein -- 7.6.2 Protein requirement of elderly people -- 7.6.3 Protein requirement of women -- 7.7 Protein requirements during pregnancy -- 7.7.1 Factorial approach -- 7.7.2 Nitrogen balance -- 7.7.3 Recommendations for protein intake during pregnancy -- 7.7.4 Diet interventions during pregnancy -- 7.7.5 Twin pregnancy -- 7.7.6 Adolescent pregnancy -- 7.8 Protein requirements during lactation -- 7.9 Areas of uncertainty -- 7.10 Summary of protein requirement values for adults, including women during pregnancy and lactation -- References -- 8. Amino acid requirements of adults -- 8.1 Requirements for indispensable amino acids -- 8.1.1 Lysine -- 8.1.2 Leucine -- 8.1.3 Isoleucine and valine -- 8.1.4 Threonine -- 8.1.5 Aromatic amino acids -- 8.1.6 Tryptophan -- 8.1.7 Sulfur amino acids -- 8.1.8 Histidine -- 8.2 Dispensable amino acids -- 8.3 Summary of amino acid requirements in adults -- 8.4 Safe intakes of indispensable amino acids -- 8.5 Indispensable amino acid requirements in elderly people -- 8.6 Requirement values compared with the amino acid content of food proteins and diets -- References -- 9. Protein and amino acid requirements of infants and children -- 9.1 Maintenance requirement for protein -- 9.1.1 Interpretation of experimental information -- 9.1.2 Variability of maintenance -- 9.2 Protein deposition -- 9.2.1 Infants and young children, age 0-2 years -- 9.2.2 Children, age 4-18 years -- 9.2.3 Variability of protein deposition.

9.2.4 Growth rates compared with previous estimates -- 9.3 Factorial estimates of protein requirements -- 9.3.1 Comparison with protein intakes of the breastfed infant -- 9.3.2 Implications of the estimated protein requirements for formula-fed infants -- 9.3.3 Average protein requirements and safe levels for infants and children from 6 months to 18 years -- 9.4 Amino acid requirements from infancy to 18 years -- 9.4.1 Infants up to 6 months -- 9.4.2 Older infants and children -- References -- 10. Catch-up growth -- 10.1 Protein requirements for rapid weight gain in the wasted child -- 10.2 Catch-up in height in stunted children -- References -- 11. Influence of infection on protein and amino acid requirements -- 11.1 Pattern of the protein and amino acid response to infection -- 11.2 Implications of HIV/AIDS -- 11.3 Recommendations for a protein allowance in infection -- References -- 12. Implications of the protein and amino acid requirements for populations in developed and developing countries -- 12.1 Protein intakes of infants associated with adequate growth rates -- 12.2 Population intakes and the new requirement values -- 12.3 Implications of the apparent inadequacy of the diets in developing countries -- References -- 13. Protein intake and health -- 13.1 Renal function -- 13.2 Bone health -- 13.3 Kidney stones -- 13.4 Cardiovascular disease -- 13.5 Cancer -- 13.6 Is there a maximum limit of dietary protein intake? -- 13.7 Conclusions -- References -- 14. Summary of requirements -- 14.1 Derivation of requirements -- 14.1.1 Safe intake for individuals and populations -- 14.1.2 Precision of estimates -- 14.1.3 Age ranges -- 14.1.4 Relation to body weight -- 14.1.5 Corrections for characteristics of the diet -- 14.2 Protein requirements of adults -- 14.3 Protein requirements of infants, children and adolescents.

14.4 Protein requirements of women during pregnancy and lactation -- 14.5 Amino acid requirements and scoring pattern of adults -- 14.6 Amino acid requirements and scoring pattern of infants, children and adolescents -- 14.7 Corrections for protein quality of the diet -- 14.8 Protein density of foods and the protein:energy ratio of the requirements -- References -- 15. Research needs -- 15.1 Recommendations for future research -- 15.2 Regulatory issues -- References -- Acknowledgements -- Annex. Statistical procedures -- Derivation of reference protein:energy ratio, individual diets -- Estimation of distribution parameters -- Regression -- Mathematical models -- Regression output -- Regression assumptions -- Analysis of variance -- References.