Muscle Protein Synthesis

Whole eggs stimulated muscle protein synthesis more than egg whites during exercise recovery despite similar blood leucine concentrations. Older adults may need about 25 to 30 grams of high-quality protein per meal to maximize muscle protein synthesis. Protein synthesis is an anabolic process in which tissue is built up. Muscle tissue constantly cycles between protein synthesis and protein breakdown. After about age 50, anabolic resistance makes muscle less responsive to amino acid signals for muscle protein synthesis. With age, the body has more difficulty regulating muscle protein synthesis and breakdown. Leucine activates mTORC1 signaling in skeletal muscle, which stimulates protein synthesis. When fasting is combined with muscle-loss risk factors, catabolic processes can dominate anabolic processes. The yolk appears to enhance the anabolic response through the food matrix beyond amino acid content alone.