Protein Requirements in Resistance-trained Males

Study Overview
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Brief Summary
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In this study, the investigators will use the minimally invasive indicator amino acid oxidation (IAAO) technique to determine protein requirements in resistance-trained males. It is hypothesized that the present study will show that protein requirements for resistance-trained males are i) greater than the current recommended dietary allowance (RDA) for non-active individual's comparable estimates, and ii) greater than existing nitrogen balance-based estimates for resistance-training individuals.

Detailed Description
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The adequate ingestion of dietary protein is the most critical nutritional factor to support the growth and maintenance of lean body mass across the lifespan. Currently, the World Health Organization/Food and Agricultural Organization (WHO/FAO) suggest that daily protein requirements in healthy, non-active adults are 0.8 g/kg/day. However, of primary interest in the present study is the impact that exercise has on the nutritional requirement for dietary protein in habitually active adults (e.g., individuals performing chronic resistance training). Protein requirements for individuals who participate in strength-based exercise training have been suggested to range from 1.2-1.7 g protein/kg/day (1), which equates to a 50-112% increase from the current RDA. The increased requirement in strength training populations may reflect the requirement for protein to repair and/or rebuild muscle tissue by promoting anabolism (2). Nutritional requirements for dietary protein in adults (both active and non-active) have traditionally been determined utilizing the antiquated and often erroneous nitrogen balance (NBAL) technique (3), which is prone to underestimating protein requirements and therefore provides challenges to making accurate nutritional recommendations (4). This observation that NBAL underestimates protein requirements in non-active individuals could suggest that protein requirements are much greater than the current World Health Organization recommendation of 0.8 g/kg/day, which was evaluated using the NBAL technique (3). As a result, there is a need to re-evaluate recommendations utilizing advanced stable isotope methodology in order to characterize how dietary protein needs may be modulated by physical activity. Recent studies using the minimally invasive indicator amino acid oxidation (IAAO) technique have suggested that protein requirements in young men are at least 50% higher than WHO/FAO guidelines based on NBAL data (4). Furthermore, resistance training has been reported to increase (according to NBAL methodology) protein requirements by up to 75% (6). Therefore, in this study, the investigators will use the IAAO technique to determine protein requirements in resistance-trained males. It is hypothesized that protein requirements for resistance-trained males will be i) greater than the current RDA for non-active individual's comparable estimates, and ii) greater than existing NBAL-based estimates for resistance-training individuals.

Official Title
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Protein Requirements in Resistance-trained Males

Conditions
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Healthy

Intervention / Treatment
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* Dietary Supplement: Amino acid intake


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy, male weight-trained individuals that have trained consistently for >1 year. 18-35 years old. Train each muscle group (i.e. chest, back, legs) at least twice a week. Body mass stable in last month Meets strength relative to body weight guidelines (see below) Bench Press: Males- body weight (kg)*1.25 Leg Press: Males- body weight (kg)* 4.0 Exclusion Criteria: Inability to meet health and physical activity guidelines according to the Physical Activity Readiness Questionnaire Inability to adhere to any of the protocol guidelines (i.e. alcohol, caffeine consumption) Regular tobacco use Illicit drug use (e.g. growth hormone, testosterone, etc.) (screened by survey sheet for training log >1 month sedentary in the last 6 months prior to study participation >30 min of continuous cardio per exercise session BMI (Body Mass Index) > 35. Individual plans to increase or decrease body mass in the next 3 months Habitually ingests greater than or equal to 3g protein kg/bw/day Use of supplements such as creatine and beta-alanine in the last 30 days.

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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Resistance-trained, adult males<br>Subjects receive varying levels of amino acid intakes ranging from 0.2-3.0g/kg/d | Dietary Supplement: Amino acid intake<br>* Amino acid intake will range between 0.2-3.0g/kg/d<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phenylalanine excretion | Expressed as µmol/kg/h; phenylalanine excretion is determined via breath enrichment of the oral tracer | Through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phenylalanine rate of appearance | In µmol/kg/h; phenylalanine rate of appearance is determined via urinary enrichment of the oral tracer | Through study completion, an average of 1 year | 
| Net Protein Balance | In µmol/kg/h; calculated as the difference between whole-body protein synthesis and protein breakdown | Through study completion, an average of 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Protein Requirements