Is It Time to Reconsider the US Recommendations for Dietary Protein and Amino Acid Intake?

Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations. New lines of evidence include: (1) re-analysis/re-interpretation of nitrogen balance data; (2) results from indicator amino acid oxidation studies; (3) studies of positive functional outcomes associated with protein intakes higher than recommended; (4) dietary guidance and protein recommendations from some professional nutrition societies; and (5) recognition that the synthesis of certain dispensable amino acids may be insufficient to meet physiological requirements more often than previously understood. The empirical estimates, theoretical calculations and clinical functional outcomes converge on a similar theme, that recommendations for intake of protein and some amino acids may be too low in several populations, including for older adults (>= 65 years), pregnant and lactating women, and healthy children older than 3 years. Additional influential factors that should be considered are protein quality that meets operational sufficiency (adequate intake to support healthy functional outcomes), interactions between protein and energy intake, and functional roles of amino acids which could impact the pool of available amino acids for use in protein synthesis. Going forward, the definition of adequacy as it pertains to protein and amino acid intake recommendations must take into consideration these critical factors.

Automated summary

Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need for re-evaluation. New evidence includes re-analysis of nitrogen balance data, studies on indicator amino acid oxidation, positive functional outcomes with higher protein intakes, guidance from nutrition societies, and recognition of insufficient amino acid synthesis. The convergence of empirical, theoretical, and clinical evidence suggests that protein and amino acid recommendations may be too low in certain populations.