Protein intake to support muscle health in a clinical setting

Adequate nutritional intake is essential to maintain nutritional status, support essential body functions, maintain quality of life, and lower disease burden. Food intake, with protein ingestion in particular and physical activity are important regulators of muscle mass. Maintenance of skeletal muscle mass is of important clinical relevance in both health and disease. This thesis investigated protein intake to support muscle health in a clinical setting. Protein intake was below 0.7 g/kg/d in both elective orthopaedic patients and patients at risk for malnutrition. Besides protein intake, physical activity is an important regulator of muscle mass maintenance. During short-term immobilization, significant amounts of muscle mass and strength were lost and there was a decrease in muscle protein synthesis rates. During a sequential two-week remobilization period, there was a partial regain of muscle mass and strength and an increase in muscle protein synthesis rates. Furthermore, the postprandial protein handling plays an important role in the anabolic response to feeding. Therefore, protein digestion and amino acid absorption kinetics following intact protein vs. free amino acids were investigated in healthy young and critically ill patients.