High-Protein Diets: What to Tell Our Patients.

Protein is a unique, essential component of our diet. There is currently great emphasis on high-protein diets, not only in the commercial food market and on social media but also in the scientific literature, with continuous debate on the need for changing current protein recommendations, in particular for older adults. Here we provide an updated perspective on the debate on high protein intake for maintaining muscle mass and function, with a focus on people who are affected by kidney disease. Several conditions such as aging, inactivity, and many chronic conditions including dialysis-treated chronic kidney disease are characterized by anabolic resistance-the need to ingest higher amounts of protein to maximally stimulate muscle protein synthesis. In addition, sedentariness and inactivity, conditions very common in developed countries, contribute to decreased muscle mass and strength. Protein intake and physical activity are the major anabolic stimuli for muscle health and function; however, protein ingestion is associated with the oxidation of excess amino acids, ureagenesis, and production of toxins. In addition, protein supplementation in the absence of resistance training produces relatively marginal effects on strength and performance in healthy subjects and older adults. On these grounds, for persons who are inactive, muscle mass and function can be better maintained by physical exercise without the use of high-protein diets.