What is Sarcopenia?

1713 WordsJul 7, 20187 Pages
Sarcopenia is a degenerative disease frequently associated with the age-related loss of muscle mass and strength. Risk of sarcopenia increases at a rate of 3-8% per decade after age 30 and continues to accelerate after the fifth decade of life (1, 616; 2, 1). Contributing factors of muscle degeneration include: sedentary lifestyle, malnutrition, reduced protein turnover rate, lowered insulin response, inflammatory changes, and decreased anabolic hormone production (3, 1073). Dietary protein is essential in order to build muscle and avoid loss of lean body mass (4, 686). Evidence indicates increased protein intake above the RDA of 0.8 g/kg per day in older adults will increase the anabolic response of muscle (3, 1073). High dietary protein…show more content…
A recent study observed the effects of amino acid infusion and results showed greater protein synthesis and no change in protein breakdown; indicating increased amino acids are anabolic to muscle in healthy older adults (3, 1076). A moderate serving of a 113 gram serving of lean protein containing 30 grams of amino acids and 10 grams of essential amino acids increases muscle protein synthesis by approximately 50% in the older adult population (1, 621). Leucine is an essential amino acid recognized as particularly important for signaling and muscle building (3, 1077). Leucine is activated through the pathway of a kinase known as mTOR (3, 1078). Messenger ribonucleic acid translation, or mTOR, targets proteins involved in mRNA translation (3, 1078). Branched chain amino acid leucine with resistance exercise training is proposed to regenerates muscle and enhances anabolic pathways while inhibiting catabolic pathways (2, 6). Leucine is a direct stimulate for muscle protein synthesis through increasing messenger ribonucleic acid translation (3, 1077). Protein synthesis was fully restored when 46% leucine enriched bolus was distributed to a sample of older adults (2, 2). Leucine at levels of 26% (1.72 g leucine) and 41% (2.79 g leucine) bolus increased muscle strength in the young but only the 41% bolus of leucine essential amino acids was effective in older adults (1, 621). Leucine-enriched amino acids, with levels of leucine
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