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 Objective & Hypothesis Methods 3 Steps in Study Results Conclusion Future Directions

Background - Protein Structural component 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

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

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

Background - Nitrogen Play many metabolic roles in the body The requirement for total nitrogen 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

Background – Nitrogen Supply Some nonessential amino acids (NEAA) may supply nitrogen better than others Rose et al. (1948) showed increased growth by 7075% in rats fed essential amino acids (EAA) + NEAA Rechcigl et al. (1957) showed different growth rates in rats Glutamate gave the largest increase in growth Followed by Alanine, Aspartate, Asparagine, Proline, and Glutamine Smallest increases in growth were Glycine and Serine

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 13 C-PHE to 13 CO 2 in breath Oxidation is inversely proportional to protein synthesis High Oxidation = Low Protein Synthesis

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

Methods Preliminary Study Adaptation Study Day

Preliminary Study Target Population: Healthy adult males Between the ages 20 -40 classified as normal body weight and BMI (18. 5 -25 kg/m 2) Background Information: Medical & Dietary histories Anthropometric measurements Body composition Resting energy expenditure (REE) Informed consent

Methods Preliminary Study Adaptation Study Day

Adaptation 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. products. nestle. ca

Methods Preliminary Study Adaptation Study Day

Study Day Diet 10 Study Days Randomized Diet: The Base Diet (0. 34 g/kg/day) Study Day 1 Base + ALA Study Day 2 Week 1 BASE (EAA) Study Day 3 Week 2 Base + SER Only EAA The Base Diet + 1 NEAA (0. 73 Study Day 4 g/kg/day) 50: 50 ratio of EAA: NEAA 5 th Meal starts the isotope tracer protocol with an oral dose of L-1 -13 C- Phenylalanine Base + GLN Study Day 5 Week 4 BASE + PRO Study Day 6 Week 5 Etc…for 10 weeks Base + ARG

Study Day Sampling Sample Collection Breath and Urine Baseline Isotopic Steady State Carbon dioxide production (VCO 2)

Sample Analysis & Statistics Multi-flow 13 CO Continuous Isotope Ratio Mass Spectrometer oxidation values analyzed using repeated measures ANOVA (Graphpad PRISM) 2

E AL AN IN E AR G IN IN AS E PA R TA AS TE PA R AG G IN LU E TA M AT G LU E TA M IN E G LY C IN E SE R IN E PR O LI N E BA S Tracer Oxidation Results – 50 Study Days 1, 2 * 1 Means ± SD 0, 8 0, 6 0, 4 0, 2 0

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

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

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

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 Biol Chem 176: 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 Nutr 63: 177 -192. Millward DJ. Methodological considerations. Proc Nutr Soc 2001; 60: 3– 5. Food and Agriculture Organization of the United Nations. Energy and Protein Requirements (1991).

QUESTIONS ? ? Thank you for listening !!

Study Day Base Diet Study Diet