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Nonessential Amino Acid Metabolism in Healthy Adult Males

Nonessential Amino Acid Metabolism in Healthy Adult Males. Leah Cooper Department of Pediatrics, University of British Columbia & Child and Family Research Institute, BC Children's Hospital. Outline. Background Protein Amino Acids Indicator Amino Acid Oxidation Technique

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Nonessential Amino Acid Metabolism in Healthy Adult Males

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  1. Nonessential Amino Acid Metabolism in Healthy Adult Males Leah Cooper Department of Pediatrics, University of British Columbia & Child and Family Research Institute, BC Children's Hospital

  2. Outline • Background • Protein • Amino Acids • Indicator Amino Acid Oxidation Technique • Objective & Hypothesis • Methods • 3 Steps in Study • Results • Conclusion • Future Directions

  3. Background - Protein • Structuralcomponent of the body • Enzymes, Hormones, Neurotransmitters, Transport Molecules • Made of 20 Amino Acids • Need all 20 in correct proportions for protein synthesis to occur in the body www.onlymyhealth.com

  4. Background – Amino Acids www.thehealthsite.com www.rpi.edu

  5. Background - Evolution http://www.nature.com/scitable/topicpage/an-evolutionary-perspective-on-amino-acids-14568445

  6. Background - Nitrogen • Play many metabolic roles in the body • The requirement for totalnitrogen is the primary determinant of total protein requirement • If total amino nitrogen is inadequate, synthesis of nonessential amino acids and thus protein is less than maximal

  7. Background – Nitrogen Supply • Some nonessential amino acids (NEAA) may supply nitrogen better than others • Rose et al. (1948) showed increased growth by 70-75% in rats fed essential amino acids (EAA) + NEAA • Rechcigl et al. (1957) showed different growth rates in rats • Glutamategave the largest increase in growth • Followed by Alanine, Aspartate, Asparagine, Proline, and Glutamine • Smallest increases in growth were Glycineand Serine

  8. Background - Indicator Amino Acid Oxidation Technique • Previous Methods (N balance) were long in duration, very invasive and impractical • The stable isotope based IAAO is rapid, minimally invasive and accurate • IAAO measures the oxidation of the tracer 13C-PHE to 13CO2 in breath • Oxidation is inversely proportional to protein synthesis • High Oxidation = Low Protein Synthesis

  9. Objective: To determine the metabolic demand of 9 of the NEAA using the indicator amino acid oxidation (IAAO) method in healthy adult males Hypothesis: There will be a hierarchy among the 9 NEAA, more specifically Alanine, Arginine, Asparagine, Aspartate, Glutamine, Glutamate, Glycine, Proline, and Serine, to supply Nitrogen to the body for the de novo synthesis of the other NEAA and for protein

  10. Methods

  11. Preliminary Study • Target Population: • Healthy adult males • Between the ages 20-40 • classified as normal body weight and BMI (18.5-25 kg/m2) • Background Information: • Medical & Dietary histories • Anthropometric measurements • Body composition • Resting energy expenditure (REE) • Informed consent

  12. Methods

  13. Adaptation products.nestle.ca • 2 days prior to each study day • Adaptation diets contain a protein intake of 1.0 g/kg and a caloric intake of 1.7 × REE • Provided as 6 milkshakes.

  14. Methods

  15. Study Day Diet Study Day 1 Study Day 2 Study Day 3 Base + ALA Week 1 BASE (EAA) Week 2 Base + SER Study Day 4 Study Day 5 Study Day 6 Base + GLN Week 4 BASE + PRO Week 5 Base + ARG Etc…for 10 weeks • 10 Study Days • Randomized • Diet: • The Base Diet (0.34 g/kg/day) • Only EAA • The Base Diet + 1 NEAA (0.73 g/kg/day) • 50:50 ratio of EAA: NEAA • 5th Meal starts the isotope tracer protocol with an oral dose of L-1-13C- Phenylalanine

  16. Study Day Sampling • Sample Collection • Breath and Urine • Baseline • Isotopic Steady State • Carbon dioxide production (VCO2)

  17. Sample Analysis & Statistics Continuous Isotope Ratio Mass Spectrometer Multi-flow 13CO2 oxidation values analyzed using repeated measures ANOVA (Graphpad PRISM)

  18. Results – 50 Study Days

  19. Conclusion • The first study to look at NEAA in humans • We suggest all NEAA can satisfy the metabolic demand for total nitrogen.

  20. Future Directions www.vancitychiro.com Determine whether a difference in NEAA metabolic demand exists in more vulnerable populations

  21. Acknowledgments • Dr. RajavelElango • Lab members • Ajinomoto Inc. Co. • Child and Family Research Institute • University of British Columbia • All my participants!

  22. References Rose, W.C., Oesterling, M.J., and Womack, M. (1948). Comparative growth on diets containing ten and nineteen amino acids with further observations upon the role of glutamic and aspartic acids. J BiolChem176: 753-762. Rechcigl Jr., M., Loosli, J. K., Williams, H. H. (1957). The net utilization of non-specific nitrogen sources for the synthesis of non-essential amino acids I. Growth and nitrogen utilization. J Nutr63: 177-192. Millward DJ. Methodological considerations. ProcNutrSoc 2001;60: 3–5. Food and Agriculture Organization of the United Nations. Energy and Protein Requirements (1991).

  23. QUESTIONS ?? Thank you for listening !!

  24. Study Day Base Diet Study Diet

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