Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit

Abstract

Adequate consumption of dietary protein is critical for the maintenance of optimal health during normal growth and aging. The current Recommended Dietary Allowance (RDA) for protein is defined as the minimum amount required to prevent lean body mass loss, but is often misrepresented and misinterpreted as a recommended optimal intake. Over the past two decades, the potential muscle-related benefits achieved by consuming higher-protein diets have become increasingly clear. Despite greater awareness of how higher-protein diets might be advantageous for muscle mass, actual dietary patterns, particularly as they pertain to protein, have remained relatively unchanged in American adults. This lack of change may, in part, result from confusion over the purported detrimental effects of higher-protein diets. This manuscript will highlight common perceptions and benefits of dietary protein on muscle mass, address misperceptions related to higher-protein diets, and comment on the translation of academic advances to real-life application and health benefit. Given the vast research evidence supporting the positive effects of dietary protein intake on optimal health, we encourage critical evaluation of current protein intake recommendations and responsible representation and application of the RDA as a minimum protein requirement rather than one determined to optimally meet the needs of the population.

Keywords: hypertrophy; musculoskeletal; protein RDA; protein balance.

Figure 1

Energy and/or dietary protein restriction induce net muscle catabolism, releasing amino acids for energy production, gluconeogenesis, and synthesis of peptide hormones, plasma proteins, immune system components, and enzymes (representative examples, not an exhaustive list; not drawn to scale). AA, amino acids; ADH, antidiuretic hormone; hGH, human growth hormone; T3, triiodothyronine; T4, thyroxine.