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Validating IAAO for Muscle Outcomes
Sponsor: University of Toronto
Summary
Consuming dietary protein stimulates whole-body and muscle protein synthesis, the latter of which is typically measured using invasive primed constant infusions of stable isotopes with concurrent muscle biopsies. Alternative non-invasive methodologies have been developed (namely the indicator amino acid oxidation (IAAO) technique) to estimate the impact of protein ingestion on whole-body protein synthesis as a proxy for determining dietary protein requirements. Given that the IAAO technique is based on principles of protein metabolism which occur in the liver, it is unclear how representative the IAAO outcomes of whole-body protein synthesis is to skeletal muscle protein synthesis. Validation of the IAAO technique against gold-standard, biopsy-derived measures of muscle metabolism (i.e., muscle protein synthesis) would assist in mitigating the invasiveness of muscle physiology and nutrition research.
Official title: Validating the Indicator Amino Acid Oxidation Technique for Muscle Outcomes
Key Details
Gender
All
Age Range
18 Years - 35 Years
Study Type
INTERVENTIONAL
Enrollment
8
Start Date
2025-12-01
Completion Date
2026-05-20
Last Updated
2026-01-05
Healthy Volunteers
Yes
Conditions
Interventions
Protein + Stable Isotope Tracer Beverage
Participants will consume 12 half-hourly (6 hours) isoenergetic, isonitrogenous beverages containing 0.9g/kg fat-free mass/day protein. Drinks will be enriched with stable isotopes \[2H5\]Phenylalanine and \[1-13C\]Phenylalanine, which will respectively allow for determination of muscle protein synthesis and whole-body protein synthesis over the subsequent 6 hours of feeding
Locations (1)
Kinesiology & Physical Education
Toronto, Ontario, Canada