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Measuring Protein Requirement Using Amino Acid Oxidation in Strength and Endurance Athletes

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02621294
Recruitment Status : Unknown
Verified November 2015 by Peter Lemon, University of Western Ontario, Canada.
Recruitment status was:  Recruiting
First Posted : December 3, 2015
Last Update Posted : December 3, 2015
Information provided by (Responsible Party):
Peter Lemon, University of Western Ontario, Canada

Brief Summary:
Our objective is to determine the dietary requirement of protein for strength and endurance exercise trained (more than 4 months training experience) individuals between 18 - 30 years of age using the indicator amino acid oxidation (IAO) method. This study will be the first to determine the required quantity of protein need per day in strength- and endurance trained young adults using the IAO method.

Condition or disease Intervention/treatment Phase
Protein Requirement of Athletes Other: Measuring protein requirement Not Applicable

Detailed Description:
The adequacy of the protein dietary requirement for strength (ST) and endurance (ET) exercise trained individuals has been a subject of considerable debate for many years and, at present, there is a discrepancy between those who establish dietary protein requirements for healthy adults and those issuing guidelines for athletes. Despite past nitrogen balance studies suggesting a greater protein requirement in ST and ET athletes, the Institute of Medicine (2005) recommends "no additional dietary protein for healthy adults undertaking resistance or endurance exercise". Current protein and amino acid (AA) requirement estimates for adults are based on nitrogen balance data which are considered to be flawed due to several methodological problems including the use of single linear regression for analyzing nonlinear data and an over/underestimation of nitrogen intake and excretion, respectively. To overcome these problems, the indicator amino acid oxidation technique (IAO) was developed for determination of dietary AA or protein requirements. The IAO method is based on the concept that when dietary protein is inadequate, all AA, including the indicator AA, will be oxidized. With increasing total protein intake, oxidation of the indicator AA will decrease. Once the requirement is met, there is no further change in the oxidation of the indicator AA and the inflection or 'breakpoint' is the estimated requirement. A mixed-effects change-point regression analysis to F13CO2 (label tracer oxidation in 13CO2 breath) in response to graded amounts of protein will be utilized to over come the limitations of linear regression previously used with nitrogen balance. These protein requirement measures using the IAO has not been carried out on ST or ET individuals previously so this will be the first study to do so. The results of this study will help determine the optimal protein requirement in ST and ET athletes which is important not only for athletes but also for older individuals whose loss of muscle mass has been linked to a variety of health concerns.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 16 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Official Title: Measuring Protein Requirement Using the Indicator Amino Acid Oxidation Method in Healthy Young Strength and Endurance Exercise Trained Individuals
Study Start Date : November 2015
Estimated Primary Completion Date : December 2016
Estimated Study Completion Date : December 2016

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Measuring protein requirement
Measuring protein requirement of athletes by feeding different amount of protein in the form of amino acid mixture and measuring their oxidation through expired CO2
Other: Measuring protein requirement
a repeated measures design will be used on each athlete receiving eight graded intakes of protein on separate days in the form of AA in random order ranging from 0.2 to 3.5 g/(kg/d). Three baseline samples of breath and urine will be collected at 60, 45 and 30 min before the stable isotope is given orally. During a period of 150 to 270 min. after stable isotope ingestion, 5 breath and urine samples (every 30 min) will be collected to determine an isotopic plateau in breath and urine. The rate of release of 13CO2 from the oxidation of L-[1-13C] phenylalanine (F 13CO2) in breath will be measured and a breakpoint analysis will determine total protein requirement

Primary Outcome Measures :
  1. measurement of protein requirement as a response of 13C oxidation (µmol . kg-1 . h-1) of 13C-Phenylalanine to varied graded intakes of protein (g/kg/d) in form of amino acid mixture based on egg protein profile [ Time Frame: within 8 hours of feeding period ]
    Oxidation of ingested L-[1-13C] phenylalanine (µmol . kg-1 . h-1) to 13CO2 (µmol . kg-1 . h-1) in response to graded intakes of protein will be measure and after determination of a plateau in oxidation curve (using change point regression analysis), break point will be defined as g/kg/d protein requirement.

Secondary Outcome Measures :
  1. Measuring body composition (percent fat and fat free mass) using air displacement plethysmography (BOD POD) [ Time Frame: 10 minutes fasted in the morning ]
    Participants will report fasted in the morning for the measurement of body fat and fat-free mass percent (%) using a BOD POD.

  2. Measuring resting energy expenditure (kcal/d) using an open-circuit indirect calorimetry [ Time Frame: 40 minutes fasted in the morning ]
    Resting energy expenditure (kcal/d) of all participants will be measured using an indirect calorimetry for duration of 40 min. by laying flat on a bed.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 30 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

Healthy strength-trained and endurance-trained (more than 3 months training experience, at least 3x week) individuals (18-30 years old).

Exclusion Criteria:

  • Unhealthy,
  • sedentary individuals,
  • those who are taking medication,
  • those outside the age range, or
  • those who have milk allergies

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02621294

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Contact: Peter Lemon, PhD 519 661-2111 ext 88139
Contact: Arash Bandegan, MSc 5196140266

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Canada, Ontario
Exercise Nutrition Research Laboratory Recruiting
London, Ontario, Canada, N6A 5B9
Contact: Peter WR Lemon, PhD    519-661-2111 ext 88139   
Principal Investigator: Peter Lemon, PhD         
Sub-Investigator: Arash Bandegan, MSc.         
Sponsors and Collaborators
University of Western Ontario, Canada
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Principal Investigator: Peter Lemon, PhD Western University
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Peter Lemon, Dr., University of Western Ontario, Canada Identifier: NCT02621294    
Other Study ID Numbers: 004
First Posted: December 3, 2015    Key Record Dates
Last Update Posted: December 3, 2015
Last Verified: November 2015
Keywords provided by Peter Lemon, University of Western Ontario, Canada:
indicator amino acid oxidation method