Old Age (Focus; Not a Recognized Condition) Clinical Trial
Official title:
Dysfunction of Nutritive Blood Flow as a Determinant of Anabolic Resistance in Older People; The Role of Essential Amino Acids in Modulating Muscle Protein Metabolism; Bolus vs. Pulse Feeding Strategies and the Ability of Arginine to Rejuvenate Microvascular Responsiveness.
The investigators plan to measure changes in muscle protein metabolism in response to
feeding, comparing between a single large essential amino acid (EAA) feed (the normal
building blocks of protein) and the provision of the same dose in 4 smaller feeds at 45min
intervals. The investigators will perform this study in healthy older (65-75y) and younger
(18-28) men. The investigators will also explore how feeding affects muscle blood flow as
this is important in the delivery of the nutrients we eat to the muscle where they are used.
The investigators plan to supplement the feed with arginine, a safe and widely found
non-essential amino acid, to explore if this can improve muscle blood flow.
We will provide a 15g mixed essential amino acid feed or 4 x 3.75g.
There is sexual dimorphism thus initially we will just recruit males. Powering calculations
dictate n=8 in each group.
We will use well established stable isotope tracer techniques (with 13C6 Phenylalanine) to
measure muscle protein synthesis and breakdown by Gas Chromatography - combustion - isotope
ratio mass spectroscopy.
We will measure leg blood flow by phase shift Doppler and muscle microvascular flow by
contrast enhanced ultrasound.
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Allocation: Non-Randomized, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment