Amino Acids

, Volume 50, Issue 12, pp 1679–1684 | Cite as

Nutritionally non-essential amino acids are dispensable for whole-body protein synthesis after exercise in endurance athletes with an adequate essential amino acid intake

  • Hiroyuki Kato
  • Kimberly A. Volterman
  • Daniel W. D. West
  • Katsuya Suzuki
  • Daniel R. MooreEmail author
Original Article


The increased protein requirement of endurance athletes may be related to the need to replace exercise-induced oxidative losses, especially of the branched-chain amino acids (BCAA). However, it is unknown if non-essential amino acids (NEAA) influence the requirement for essential amino acids (EAA) during post-exercise recovery. Seven endurance-trained males ran 20 km prior to consuming [13C]phenylalanine, sufficient energy, and: (1) deficient protein (BASE); (2) BASE supplemented with sufficient BCAA (BCAAsup); (3) an equivalent EAA intake as BCAA (LowEAA), and; (4) sufficient EAA intake (HighEAA). [13C]Phenylalanine oxidation (the reciprocal of protein synthesis) for BCAAsup and HighEAA (0.54 ± 0.15, 0.49 ± 0.11 µmol kg−1 h−1; Mean ± SD) were significantly lower than BASE (0.74 ± 0.14 µmol kg−1 h−1; P < 0.01 for both) and LowEAA (0.70 ± 0.11 µmol kg−1 h−1; P < 0.05 and 0.01, respectively). Our results suggest that exogenous NEAA are dispensable for whole-body protein synthesis during recovery from endurance exercise provided sufficient EAA are consumed. Endurance athletes who may be at risk of not meeting their elevated protein requirements should prioritize the intake of EAA-enriched foods and/or supplements.


Endurance training Amino acid requirement Post-exercise recovery Protein synthesis Non-essential amino acids 



Low protein diet


Branched-chain amino acids


BASE supplemented branched-chain amino acids


Essential amino acid


Exercise-induced energy expenditure


13CO2 excretion


Fat-free mass


Fat mass


High dose of essential amino acids


Heart rate


Indicator amino acid oxidation


Low dose of essential amino acids


Non-essential amino acid


Phenylalanine oxidation


Whole-body phenylalanine flux


Recommended daily allowance


Resting energy expenditure


CO2 production


Author contribution

The authors’ responsibilities were as follows: HK and DRM designed the research; HK, KAV and DW conducted research and analyzed the data; HK performed the statistical analysis; HK and DRM wrote the manuscript with assistance from KAV and DW; KS consulted the study design and manuscript writing. HK and DRM had primary responsibility for final content. All authors read and approved the final manuscript.


This study was funded by Ajinomoto Co., Inc.

Compliance with ethical standards

Conflict of interest

Some of the authors (HK and KS) are employees of Ajinomoto. DRM has received research grant from Ajinomoto Co., Inc.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study was approved by the research ethics board of the University of Toronto (No. 33245) and the institutional review board of Ajinomoto Co., Inc (No. 2016-017). This trial was registered at as NCT02874638.

Informed consent

Informed consent was obtained from all individual participants included in the study, after informing the purpose of the study, the experimental procedures involved and all the potential risks involved.


  1. Ball RO, Bayley HS (1986) Influence of dietary protein concentration on the oxidation of phenylalanine by the young pig. Br J Nutr 55:651–658CrossRefGoogle Scholar
  2. Borsheim E, Tipton KD, Wolf SE, Wolfe RR (2002) Essential amino acids and muscle protein recovery from resistance exercise. Am J Physiol Endocrinol Metab 283:E648–E657. CrossRefPubMedGoogle Scholar
  3. Burd NA, Tang JE, Moore DR, Phillips SM (2009) Exercise training and protein metabolism: influences of contraction, protein intake, and sex-based differences. J Appl Physiol 1985 106:1692–1701. CrossRefPubMedGoogle Scholar
  4. Burke LM, Hawley JA, Wong SH, Jeukendrup AE (2011) Carbohydrates for training and competition. J Sports Sci 29(Suppl 1):S17–S27. CrossRefPubMedGoogle Scholar
  5. Crozier SJ, Kimball SR, Emmert SW, Anthony JC, Jefferson LS (2005) Oral leucine administration stimulates protein synthesis in rat skeletal muscle. J Nutr 135:376–382CrossRefGoogle Scholar
  6. Elango R, Ball RO, Pencharz PB (2008) Indicator amino acid oxidation: concept and application. J Nutr 138:243–246CrossRefGoogle Scholar
  7. Hankard RG, Haymond MW, Darmaun D (1996) Effect of glutamine on leucine metabolism in humans. Am J Physiol 271:E748–E754PubMedGoogle Scholar
  8. Humayun MA, Elango R, Ball RO, Pencharz PB (2007) Reevaluation of the protein requirement in young men with the indicator amino acid oxidation technique. Am J Clin Nutr 86:995–1002. CrossRefPubMedGoogle Scholar
  9. Kato H, Suzuki K, Bannai M, Moore DR (2016) Protein requirements are elevated in endurance athletes after exercise as determined by the indicator amino acid oxidation method. PLoS One 11:e0157406. CrossRefPubMedPubMedCentralGoogle Scholar
  10. Kato H, Suzuki K, Bannai M, Moore DR (2018) Branched-chain amino acids are the primary limiting amino acids in the diets of endurance-trained men after a bout of prolonged exercise. J Nutr 148:925–931. CrossRefPubMedGoogle Scholar
  11. Kim IY, Schutzler S, Schrader A, Spencer HJ, Azhar G, Ferrando AA, Wolfe RR (2016) The anabolic response to a meal containing different amounts of protein is not limited by the maximal stimulation of protein synthesis in healthy young adults. Am J Physiol Endocrinol Metab 310:E73–E80. CrossRefPubMedGoogle Scholar
  12. Leah C, Ball R, Sakai R, Elango R (2015) Nonessential amino acids as nitrogen sources in adult men examined using the indicator amino acid oxidation tecnique. FASEB J 29(742):711Google Scholar
  13. Margaria R, Cerretelli P, Aghemo P, Sassi G (1963) Energy cost of running. J Appl Physiol 18:367–370CrossRefGoogle Scholar
  14. Matthews DE, Motil KJ, Rohrbaugh DK, Burke JF, Young VR, Bier DM (1980) Measurement of leucine metabolism in man from a primed, continuous infusion of l-[1-3C]leucine. Am J Physiol 238:E473–E479. CrossRefPubMedGoogle Scholar
  15. Moore DR, Camera DM, Areta JL, Hawley JA (2014) Beyond muscle hypertrophy: why dietary protein is important for endurance athletes. Appl Physiol Nutr Metab 39:987–997. CrossRefPubMedGoogle Scholar
  16. Mourtzakis M, Saltin B, Graham T, Pilegaard H (2006) Carbohydrate metabolism during prolonged exercise and recovery: interactions between pyruvate dehydrogenase, fatty acids, and amino acids. J Appl Physiol (1985) 100:1822–1830. CrossRefGoogle Scholar
  17. Rafii M et al (2015) Dietary protein requirement of female adults > 65 years determined by the indicator amino acid oxidation technique is higher than current recommendations. J Nutr 145:18–24. CrossRefPubMedGoogle Scholar
  18. Shiman R, Gray DW (1998) Formation and fate of tyrosine. Intracellular partitioning of newly synthesized tyrosine in mammalian liver. J Biol Chem 273:34760–34769CrossRefGoogle Scholar
  19. Stephens TV, Payne M, Ball RO, Pencharz PB, Elango R (2015) Protein requirements of healthy pregnant women during early and late gestation are higher than current recommendations. J Nutr 145:73–78. CrossRefPubMedGoogle Scholar
  20. Suryawan A, Nguyen HV, Almonaci RD, Davis TA (2012) Differential regulation of protein synthesis in skeletal muscle and liver of neonatal pigs by leucine through an mTORC1-dependent pathway. J Anim Sci Biotechnol. CrossRefPubMedPubMedCentralGoogle Scholar
  21. Tang M, McCabe GP, Elango R, Pencharz PB, Ball RO, Campbell WW (2014) Assessment of protein requirement in octogenarian women with use of the indicator amino acid oxidation technique. Am J Clin Nutr 99:891–898. CrossRefPubMedPubMedCentralGoogle Scholar
  22. Tarnopolsky M (2004) Protein requirements for endurance athletes. Nutrition 20:662–668. CrossRefPubMedGoogle Scholar
  23. Thomas DT, Erdman KA, Burke LM (2016) American College of Sports medicine joint position statement. Nutrition and athletic performance. Med Sci Sports Exerc 48:543–568. CrossRefPubMedGoogle Scholar
  24. Van Hall G, Saltin B, Wagenmakers AJ (1999) Muscle protein degradation and amino acid metabolism during prolonged knee-extensor exercise in humans. Clin Sci (Lond) 97:557–567CrossRefGoogle Scholar
  25. van Wijck K et al (2013) Dietary protein digestion and absorption are impaired during acute postexercise recovery in young men. Am J Physiol Regul Integr Comp Physiol 304:R356–R361. CrossRefPubMedGoogle Scholar
  26. Wagenmakers AJ (1998) Muscle amino acid metabolism at rest and during exercise: role in human physiology and metabolism. Exerc Sport Sci Rev 26:287–314CrossRefGoogle Scholar
  27. Wang J et al (2008) Gene expression is altered in piglet small intestine by weaning and dietary glutamine supplementation. J Nutr 138:1025–1032CrossRefGoogle Scholar
  28. Wasserman DH, Cherrington AD (1991) Hepatic fuel metabolism during muscular work: role and regulation. Am J Physiol 260:E811–E824PubMedGoogle Scholar
  29. Wilkinson SB, Kim PL, Armstrong D, Phillips SM (2006) Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise. Appl Physiol Nutr Metab 31:518–529. CrossRefPubMedGoogle Scholar
  30. Wu G (2013) Amino acids: biochemistry and nutrition. CRC Press, Boca RatonCrossRefGoogle Scholar
  31. Wu G et al (2013) Dietary requirements of “nutritionally non-essential amino acids” by animals and humans. Amino Acids 44:1107–1113. CrossRefPubMedGoogle Scholar
  32. Zello GA, Pencharz PB, Ball RO (1990) Phenylalanine flux, oxidation, and conversion to tyrosine in humans studied with l-[1-13C]phenylalanine. Am J Physiol 259:E835–E843PubMedGoogle Scholar
  33. Zello GA, Wykes LJ, Ball RO, Pencharz PB (1995) Recent advances in methods of assessing dietary amino acid requirements for adult humans. J Nutr 125:2907–2915PubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  • Hiroyuki Kato
    • 1
    • 2
  • Kimberly A. Volterman
    • 2
  • Daniel W. D. West
    • 2
  • Katsuya Suzuki
    • 1
  • Daniel R. Moore
    • 2
    Email author
  1. 1.Frontier Research Laboratories, Institute for InnovationAjinomoto Co., IncKawasakiJapan
  2. 2.Faculty of Kinesiology and Physical EducationUniversity of TorontoTorontoCanada

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