The progressive loss of skeletal muscle mass and function with advancing age, termed sarcopenia, contributes substantially to disability, physical dependence, and mortality among older adults. Aging is associated with an attenuated muscle protein synthetic response to the ingestion of small to moderate protein doses compared to younger persons. Several studies have reported that the acute, postprandial muscle protein synthesis (MPS) response to a suboptimal protein dose is enhanced when the leucine content of the protein bolus is increased. This indicates that supplementing the lower-protein daily meals (i.e., breakfast and lunch) with leucine may represent a practical strategy to augment the MPS response to these meals and, subsequently, attenuate sarcopenic muscle mass loss over time. In addition, LC n-3 PUFA supplementation has been shown to enhance the MPS response to amino acid infusion older adults suggesting that combined leucine and LC n-3 PUFA supplementation be particularly effective for improving daily MPS, muscle mass and function in older adults.
This study will examine the effect of leucine-enriched protein supplementation, alone and in combination with long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA), on muscle mass and function in older adults at risk of sarcopenia.~The investigators hypothesize that LC n-3 PUFA supplementation will further enhance the efficacy of the leucine-enriched protein.