Longevity & AgingBeyond Protein Grams: Why Amino Acid Quality Determines Who Actually Benefits
Meeting the RDA for total protein does not guarantee adequate essential amino acid (EAA) intake, particularly when diets rely on lower-quality plant proteins. This 2025 critical review synthesizes chemical scoring methods (DIAAS, PDCAAS) with stable isotope tracer techniques to provide a comprehensive picture of dietary protein quality. Key factors include EAA density per calorie, true ileal digestibility, bioavailability, and capacity to stimulate muscle protein synthesis. Practical modifiers—cooking method, food particle size, antinutrient content, and storage conditions—meaningfully shift protein quality up or down. Older adults face compounding challenges including reduced chewing efficiency and a higher leucine threshold for muscle protein synthesis, making EAA density especially critical in this population.
