QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zello, G. A. Articles by Pencharz, P. B. Search for Related Content PubMed PubMed Citation Articles by Zello, G. A. Articles by Pencharz, P. B.

Recent Advances in Methods of Assessing Dietary Amino Acid Requirements for Adult Humans^1,2,

Gordon A. Zello^*, Linda J. Wykes^,**,3, Ronald O. Ball^**,, and Paul B. Pencharz^,**,,4

^* College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5C9 The Research Institute, The Hospital for Sick Children ^** Department of Nutritional Sciences Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada M5G 1X8 Department of Animal and Poultry Science, University of Guelph, Ontario, Canada N1G 2W1

The requirements for the indispensable amino acids have been determined by a number of different methods. Historically, descriptive or gross measures like growth and nitrogen balance have been used. However, technological advancements in recent years have resulted in the use of more precise and mechanistic metabolic approaches (i.e., plasma amino acid concentrations, amino acid oxidation, indicator amino acid oxidation) to examine requirement. Nevertheless, the current recommendations are still based on nitrogen balance studies. Requirement estimates based on other methodologies, such as plasma amino acid concentrations and direct amino acid oxidation, suggest that the requirement estimates derived from nitrogen balance experiments are too low. However, these higher estimates have also been criticized on conceptual and methodological grounds, resulting in considerable controversy in the area of indispensable amino acid requirements. A new technique, indicator amino acid oxidation, addresses many of the criticisms directed toward the alternative methods and the proposed higher requirement estimates. This paper reviews the current knowledge of amino acid requirements and makes recommendations in light of new information that has been provided from recent indicator amino acid oxidation research. It is concluded that the nitrogen balance-based estimates of amino acid requirement are too low.

KEY WORDS: • nitrogen balance • amino acids • oxidation • stable isotopes • humans

¹ Supported by the Medical Research Council of Canada (Grants MA10321 and MT5466) and the Natural Sciences and Engineering Research Council of Canada (Grant OGP0138042).

² The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC section 1734 solely to indicate this fact.

³ Present address: School of Dietetics and Human Nutrition, McGill University, Quebec, Canada H9X 3V9.

⁴ To whom correspondence should be addressed.

Manuscript received 21 December 1994. Revision accepted 11 September 1995.

This article has been cited by other articles:

				K. P Chapman, G. Courtney-Martin, A. M Moore, R. O Ball, and P. B Pencharz Threonine requirement of parenterally fed postsurgical human neonates Am. J. Clinical Nutrition, January 1, 2009; 89(1): 134 - 141. [Abstract] [Full Text] [PDF]

				D. R Moore, M. J Robinson, J. L Fry, J. E Tang, E. I Glover, S. B Wilkinson, T. Prior, M. A Tarnopolsky, and S. M Phillips Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men Am. J. Clinical Nutrition, January 1, 2009; 89(1): 161 - 168. [Abstract] [Full Text] [PDF]

				G. Courtney-Martin, K. P Chapman, A. M Moore, J. H Kim, R. O Ball, and P. B Pencharz Total sulfur amino acid requirement and metabolism in parenterally fed postsurgical human neonates Am. J. Clinical Nutrition, July 1, 2008; 88(1): 115 - 124. [Abstract] [Full Text] [PDF]

				R. Elango, R. O. Ball, and P. B. Pencharz Indicator Amino Acid Oxidation: Concept and Application J. Nutr., February 1, 2008; 138(2): 243 - 246. [Abstract] [Full Text] [PDF]

				M. A Humayun, R. Elango, R. O Ball, and P. B Pencharz Reevaluation of the protein requirement in young men with the indicator amino acid oxidation technique Am. J. Clinical Nutrition, October 1, 2007; 86(4): 995 - 1002. [Abstract] [Full Text] [PDF]

				R. Elango, M. A Humayun, R. O Ball, and P. B Pencharz Lysine requirement of healthy school-age children determined by the indicator amino acid oxidation method Am. J. Clinical Nutrition, August 1, 2007; 86(2): 360 - 365. [Abstract] [Full Text] [PDF]

				D. E. Matthews An Overview of Phenylalanine and Tyrosine Kinetics in Humans J. Nutr., June 1, 2007; 137(6): 1549S - 1555S. [Abstract] [Full Text] [PDF]

				J. W-C. Hsu, W. Kriengsinyos, L. J. Wykes, M. Rafii, L. A. Goonewardene, R. O. Ball, and P. B. Pencharz Leucine Is Not a Good Choice as an Indicator Amino Acid for Determining Amino Acid Requirements in Men J. Nutr., April 1, 2006; 136(4): 958 - 964. [Abstract] [Full Text] [PDF]

				J. M Turner, M. A Humayun, R. Elango, M. Rafii, V. Langos, R. O Ball, and P. B Pencharz Total sulfur amino acid requirement of healthy school-age children as determined by indicator amino acid oxidation technique Am. J. Clinical Nutrition, March 1, 2006; 83(3): 619 - 623. [Abstract] [Full Text] [PDF]

				A. V. Kurpad, M. M. Regan, T. Raj, and J. V. Gnanou Branched-Chain Amino Acid Requirements in Healthy Adult Human Subjects J. Nutr., January 1, 2006; 136(1): 256S - 263S. [Abstract] [Full Text] [PDF]

				C. C. Metges, K. J. Petzke, G. Backes, A. Elsner, P. Junghans, M. Derno, G. Nurnberg, and U. Hennig Response to lysine in a wheat gluten diet in adult minipigs after short-and long-term dietary adaptation as assessed with an indicator amino acid oxidation and balance technique J Anim Sci, April 1, 2005; 83(4): 833 - 841. [Abstract] [Full Text] [PDF]

				R. Riazi, M. Rafii, J. T. R. Clarke, L. J. Wykes, R. O. Ball, and P. B. Pencharz Total branched-chain amino acids requirement in patients with maple syrup urine disease by use of indicator amino acid oxidation with L-[1-13C]phenylalanine Am J Physiol Endocrinol Metab, July 1, 2004; 287(1): E142 - E149. [Abstract] [Full Text] [PDF]

				G. Courtney-Martin, R. Bross, M. Raffi, J. T. R. Clarke, R. O. Ball, and P. B. Pencharz Phenylalanine requirement in children with classical PKU determined by indicator amino acid oxidation Am J Physiol Endocrinol Metab, December 1, 2002; 283(6): E1249 - E1256. [Abstract] [Full Text] [PDF]