Leucine-enriched Nutraceutical and Attenuating Muscle Loss
Condition: Muscle Loss
Study type: Interventional

Summary: 
      This leucine-enriched protein gummy (as a gummy bar/slab) will be studied to address
      age-related loss of muscle mass and strength/function in older persons. The product is small
      volume (approximately 35 g per serve) and low energy (approximately 100 kcal per serve). It
      is easy to chew and swallow with the consistency of a firm Jello. In addition, it contains an
      effective dose of leucine in a high-quality protein matrix consisting of milk proteins.
      Understanding the efficacy of this product on changes in levels of blood amino acids and the
      molecular signaling required to enhance muscle growth will provide helpful insight for the
      suggestion of supplemental use.
    

Detailed description: 
      General experimental design:

      Pre-testing will require participants to become familiarized with performing maximal
      voluntary isometric contractions, as well as touring the laboratory facilities. Participants
      will be asked to complete dietary records for three days to determine habitual caloric
      intake. The experimental trial will be conducted in three phases. A baseline run-in phase
      (Phase 1) during which participants will consume a diet matching their estimated energy
      requirement to put them in a weight-stable phase. Energy requirements will be estimated using
      the Harris Benedict equation using an appropriate physical activity factor based on interview
      responses to a standard activity questionnaire. Participants will then be assigned to either
      the comparator group (n=10) or leucine-enriched protein food group (n=10). For the subsequent
      10d (Phase 2), participants will undergo a period of step reduction (< 1000 steps.d-1) whilst
      in a 500 kcal.d-1 deficit that will be adjusted for the reduced physical activity due to the
      step reduction. The reason for inducing an energy deficit is to mimic a situation where older
      individuals will be both physically inactive and 'undernourished', such as during home-bound
      periods of sickness or while in hospital. After completing Phase 2, participants will then
      return to their normal step count (from measured habitual steps pre-intervention) under
      energy balanced conditions for 10d that will serve as a recovery phase, Phase 3. We will
      complete assessments of body composition, leg lean mass, maximal voluntary isometric
      strength, measures of physical performance, and rate of force development will be made.
      Skeletal muscle biopsies will be obtained for biochemical analysis. At these time points,
      maximal voluntary isometric force, maximal leg press strength, a battery of physical
      performance measures and body composition will once again be obtained.
    

Intervention name(s): Leucine-enriched protein gel delivery system; Milk protein gel delivery system
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Leucine enriched; Non-leucine enriched
Intervention MeSH terms: Caseins
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: parallel group design (with repeated measurements within each group)
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Leucine; Protein; Supplementation