Rate-limiting Amino Acids in Endurance-trained Athlete

Study Overview
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Brief Summary
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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.

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

Conditions
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Increased Metabolic Requirement, Healthy

Intervention / Treatment
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* Dietary Supplement: Base protein
* Dietary Supplement: Sufficient protein
* Dietary Supplement: Branched chain amino acids
* Dietary Supplement: Essential amino acids
* Dietary Supplement: Non essential amino acids


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Base protein<br>0.8 g/kg/d of protein provided as crystalline amino acid made after egg protein. | Dietary Supplement: Base protein<br>* 0.8 g/kg/d of protein provided as crystalline amino acid modeled after egg protein<br>|
| Experimental: Sufficient protein<br>1.75 g/kg/d protein provided as crystalline amino acid made after egg protein. | Dietary Supplement: Sufficient protein<br>* 1.75 g/kg/d protein provided as crystalline amino acid modeled after egg protein.<br>|
| Experimental: Base + BCAA<br>Base protein intake + Branched chain amino acids | Dietary Supplement: Base protein<br>* 0.8 g/kg/d of protein provided as crystalline amino acid modeled after egg protein<br>Dietary Supplement: Branched chain amino acids<br>* Branched chain amino acids modeled after egg protein.<br>|
| Experimental: Base + EAA<br>Base protein intake + essential amino acids. | Dietary Supplement: Base protein<br>* 0.8 g/kg/d of protein provided as crystalline amino acid modeled after egg protein<br>Dietary Supplement: Essential amino acids<br>* Essential amino acids modeled after egg protein.<br>|
| Experimental: Base + NEAA<br>Base protein intake + non essential amino acids | Dietary Supplement: Base protein<br>* 0.8 g/kg/d of protein provided as crystalline amino acid modeled after egg protein<br>Dietary Supplement: Non essential amino acids<br>* Non essential amino acids modeled after egg protein.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 13CO2 (carbon dioxide) excretion rate (μmol/kg/h) | 8 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. | At 8 hours after the end of exercise | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| [13C]phenylalanine oxidation rate (μmol/kg/h) | 8 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. | at 8 hours after the end of exercise |