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Post-prandial tracer studies of protein and amino acid utilisation: what can they tell us about human amino acid and protein requirements?
Millward, D Joe.
Afiliación
  • Millward DJ; Department of Nutritional Sciences, School of Biosciences & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
Br J Nutr ; 131(12): 2005-2030, 2024 06 28.
Article en En | MEDLINE | ID: mdl-38606599
ABSTRACT
Nitrogen balance (NB), the principal methodology used to derive recommendations for human protein and amino acid requirements, has been widely criticised, and calls for increased protein and amino acid requirement recommendations have been made, often on the basis of post-prandial amino acid tracer kinetic studies of muscle protein synthesis, or of amino acid oxidation. This narrative review considers our knowledge of the homeostatic regulation of the FFM throughout the diurnal cycle of feeding and fasting and what can and has been learnt from post-prandial amino acid tracer studies, about amino acid and protein requirements. Within the FFM, muscle mass in well fed weight-stable adults with healthy lifestyles appears fixed at a phenotypic level within a wide range of habitual protein intakes. However homoeostatic regulation occurs in response to variation in habitual protein intake, with adaptive changes in amino acid oxidation which influence the magnitude of diurnal losses and gains of body protein. Post-prandial indicator amino acid oxidation (IAAO) studies have been introduced as an alternative to NB and to the logistically complex 24 h [13C-1] amino acid balance studies, for assessment of protein and amino acid requirements. However, a detailed examination of IAAO studies shows both a lack of concern for homeostatic regulation of amino acid oxidation and  major flaws in their design and analytical interpretation, which seriously constrain their ability to provide reliable values. New ideas and a much more critical approach to existing work is needed if real progress is to be made in the area.
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Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Oxidación-Reducción / Proteínas en la Dieta / Periodo Posprandial / Aminoácidos / Necesidades Nutricionales Límite: Humans Idioma: En Revista: Br J Nutr Año: 2024 Tipo del documento: Article

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Oxidación-Reducción / Proteínas en la Dieta / Periodo Posprandial / Aminoácidos / Necesidades Nutricionales Límite: Humans Idioma: En Revista: Br J Nutr Año: 2024 Tipo del documento: Article