[Protein intake and preservation of function in old age : Current evidence and present research gaps]

In the past, large observational cohort studies suggested that a higher protein intake might slow the age-associated loss of muscle mass and muscle strength. This observation led to the conclusion that a higher protein intake may contribute to a preservation of function and to the prevention of sarcopenia. Therefore, the German Nutrition Society increased their recommendation for daily protein intake in adults aged ≥ 65 years from 0.8 to 1.0 g/kg body weight (estimated value); however, current data indicate that a higher protein intake has no beneficial effect on muscle mass or muscle strength in healthy older adults. Yet, in patients with sarcopenia a beneficial effect on muscle health can be assumed for an increase in protein intake when combined with resistance exercise, while the evidence for an increase in protein intake alone is less convincing. Current research gaps pertain to the effect of different types of protein on muscle mass and muscle strength as well as to the relevance of a vegan diet for healthy aging.