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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
108
Protein-free, LC n-3 PUFA-free juice based supplement
Leucine-enriched whey protein
LC n-3 PUFA
University College Dublin
Dublin, Ireland
Appendicular skeletal muscle mass
Assessed via dual energy x-ray absorptiometry
Time frame: 6 months
Isometric knee extension strength
Maximal voluntary contraction
Time frame: 6 months
Physical performance
Short physical performance battery, single leg stand, timed up and go
Time frame: 6 months
Metabolomics
Assessed using nuclear magnetic resonance (NMR) spectroscopy
Time frame: 6 months
Transcriptomics
Assessed via RNA Sequencing
Time frame: 6 months
Thigh muscle mass
Assessed in dominant leg via MRI in sub cohort (n=39)
Time frame: 6 months
Muscle protein synthesis
Measured as fractional synthetic rate (%/day) over a 3-d period at baseline and end of study
Time frame: 6 months
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