Protein Requirements in Resistance-trained Males
Condition: Healthy
Study type: Interventional

Summary: 
      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: 
      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.
    

Intervention name(s): Amino acid intake
Intervention type(s): Dietary Supplement
Intervention description(s): Amino acid intake will range between 0.2-3.0g/kg/d
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Protein Requirements