[Protein supplementation to prevent loss in muscle mass and strength in frail older patients: a review].

Minimum levels of protein intake are essential for the preservation of muscle mass and function, which is a major preventive issue of successful aging. Epidemiological studies suggest strong associations between protein intake and the different elements of sarcopenia, namely maintenance of lean mass and muscle strength. Most often, protein intakes among older patients are below requirements, independently from situations of under nutrition. This opens the path for nutritional interventions to prevent the consequences of sarcopenia in older patients. Isolated amino-acids such as leucine have shown positive effects in the short term only. The positive effects of protein supplementations on muscle strength and function are currently not established in the absence of concomitant exercise training. The highest level of evidence supports interventions combining exercise and nutrition.