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.

Inclusion Criteria:

• Age: ≥65 y
• Sex: males and females
• Low muscle mass (assessed via bioelectrical impedance analysis using cut-offs from Janssen, 2004) and/or low handgrip strength (< 30 kg men, <20kg women)

Exclusion Criteria:

• BMI >35 kg/m2
• Cancer - malignancy in the past 5 years
• Multiple Sclerosis, Parkinsons Disease
• Chronic kidney disease
• Liver failure
• Diabetes
• Conditions that will affect ability to consume, digest and/or absorb the study drink (i.e. cows milk protein allergy, inflammatory bowel disease)
• Smokers
• Cognitive function < 21 on Mini-Mental State Examination
• Excess alcohol intake
• Regular resistance training
• Total walking incapacity
• Musculoskeletal or neuromuscular impairments that could interfere with strength testing
• Medications interfering with muscle metabolism
• Adherence to a high energy or high protein diet three months before starting and during the study. Use of protein containing or amino acid containing nutritional supplements three months before starting and during the study.
• High consumers of oily fish.
• Weight change > 3 kg past 3 months