Sarcopenia
Protein intake and physical activity are important stimuli for muscle protein synthesis. A number of expert groups have proposed an increase in dietary protein recommendations for older age groups to 1.0-1.2 g/kg body weight per day.
Key nutrient supplementation in older adults is of interest in the prevention of sarcopenia and frailty, since it is a simple, low-cost treatment approach without major side effects.
Protein (nutrient)
There are nine essential amino acids which humans must obtain from their diet in order to prevent protein-energy malnutrition and resulting death. They are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine. There has been debate as to whether there are 8 or 9 essential amino acids. The consensus seems to lean towards 9 since histidine is not synthesized in adults. There are five amino acids which humans are able to synthesize in the body. These five are alanine, aspartic acid, asparagine, glutamic acid and serine. There are six conditionally essential amino acids whose synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. These six are arginine, cysteine, glycine, glutamine, proline and tyrosine.