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Rate-limiting Amino Acids in Endurance-trained Athlete

Application of Indicator Amino Acid Oxidation Method to Investigate the Rate-limiting Amino Acids in Endurance Trained Athlete

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT02628249
Acronym
EA
Enrollment
5
Registered
2015-12-11
Start date
2015-09-30
Completion date
2017-12-31
Last updated
2019-04-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Increased Metabolic Requirement, Healthy

Brief summary

Protein requirements in individuals who participate in endurance-based exercise training have been suggested to be greater than the current recommended dietary allowance (RDA). The biological value of protein depends on the amino acid composition. As liebig's law of the minimum, the protein synthesis is limited due to the lack of single rate limiting amino acid. In this case, the first rate limiting amino acid determines protein intakes to maximize the protein synthesis. Adding a small amount of rate-limiting amino acid to the diet improves the biological value of its protein diet. The indicator amino acid oxidation (IAAO) method has clarified the individual amino acid requirement in children, normal healthy adult and clinical populations. however, the IAAO method has never been utilized for determining the first rate limiting amino acid. Therefore, the purpose of this study is to address of IAAO method to be applied for determining the rate-limiting amino acid in endurance athlete.

Interventions

DIETARY_SUPPLEMENTBase protein

0.8 g/kg/d of protein provided as crystalline amino acid modeled after egg protein

DIETARY_SUPPLEMENTSufficient protein

1.75 g/kg/d protein provided as crystalline amino acid modeled after egg protein.

DIETARY_SUPPLEMENTBranched chain amino acids

Branched chain amino acids modeled after egg protein.

DIETARY_SUPPLEMENTEssential amino acids

Essential amino acids modeled after egg protein.

DIETARY_SUPPLEMENTNon essential amino acids

Non essential amino acids modeled after egg protein.

Sponsors

University of Toronto
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
MALE
Age
18 Years to 35 Years
Healthy volunteers
Yes

Inclusion criteria

Gender: Male Age limit: Minimum age 18 years - Maximum age 35 years Accepts Healthy Volunteers : yes Inclusion Criteria: * Endurance-trained participants who regularly more than 40 km/week * Ability to perform the exercise stimulus (20 km run) on metabolic trial.

Exclusion criteria

* Inability to meet health and physical activity guidelines according to the physical activity readiness questionnaire (PAR-Q+) * Inability to adhere to any of the protocol guidelines (i.e. alcohol, caffeine consumption) * Regular tobacco use * Illicit drug use

Design outcomes

Primary

MeasureTime frameDescription
13CO2 (carbon dioxide) excretion rate (μmol/kg/h)At 8 hours after the end of exercise8 hours after exercise followed by ingesting 13C-labelled phenylalanine and one of 5 different amount of amino acids intake, 13CO2 excretion rate is determined by multiplying the enrichment of 13CO2 in breath measured by Mass spectrometry and CO2 production rate measured by metabolic cart.

Secondary

MeasureTime frameDescription
[13C]phenylalanine oxidation rate (μmol/kg/h)at 8 hours after the end of exercise8 hours after exercise followed by ingesting 13C-labelled phenylalanine and one of 5 different amount of amino acids intake, 13CO2 excretion rate is determined dividing 13CO2 excretion rate by urinary enrichment of 13C-phenylalanine in breath measured by Mass spectrometry, and CO2 production rate measured by metabolic cart.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 6, 2026