Influence of Reduced Daily Step Count and Anabolic Interventions on Muscle Protein Metabolism in Older Persons

NCT02347137 | Completed DMC

• 1 other identifier: 11-267
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

As the loss of muscle mass with aging is associated with a dysregulation of muscle protein synthesis (MPS) that is generally characterized by an 'anabolic resistance' to nutrients, the primary outcome of the trial is to investigate the effect of a mixed macronutrient beverage on post-prandial myofibrillar MPS. However, the 'anabolic resistance' of aging may be predominantly influenced by the contractile activity of skeletal muscle; for example, the investigators have demonstrated that 2 weeks of reduced habitual activity (i.e. daily step count) induces anabolic resistance in otherwise healthy older adults. In contrast, resistance exercise is well-known to enhance muscle mass and can increase the sensitivity of skeletal muscle to dietary amino acids. Therefore, all participants will undergo a 2-week reduced step count intervention combined with a unilateral leg resistance exercise protocol to induce an 'unhealthy' or 'anabolically resistant' leg and a relatively 'healthy' or 'anabolically sensitive' leg, respectively; this within subject model will be utilized to investigate the effect of the mixed macronutrient beverage in both relatively 'healthy' and 'unhealthy' older muscle. The investigators will also measure changes in muscle mass, muscle function, and cardiovascular health of both legs before and after the 2-week intervention to determine the effect of reduced activity and the protective effect of minimal, low-intensity exercise on these outcomes.

Conditions

Older Adults; Muscle Protein Synthetic Response to Protein; Reduced Physical Activity

Outcome Measures

Primary Outcomes (1)

• Myofibrillar fractional synthetic rate will be measured using 13C6 ring phenylalanine

  analysis

  7 hours

Secondary Outcomes (3)

• body composition (lean body mass, fat mass, leg lean mass, leg fat mass) will be measured using dual energy xray absorptiometry

  14 days

• leg muscle strength (leg press and leg extension 1 repetition maximum [1-RM], peak knee extensor torque) will be measured using a dynamometer

  14 days

• vascular function (femoral blood flow, femoral artery diameter, leg pulse) will be measured using doppler ultrasound

  14 days

Study Arms (3)

Isolated Whey Protein

ACTIVE COMPARATOR

20 g isolated whey protein + 15 g non-essential amino acids

Other: step-reduction; Other: step-reduction plus resistance exercise

Micellar Whey Protein

EXPERIMENTAL

20 g micellar whey protein + 15 g non-essential amino acids

Other: step-reduction; Other: step-reduction plus resistance exercise

Micellar Whey Protein + Citrulline

EXPERIMENTAL

20 g micellar whey protein + 5 g citrulline

Other: step-reduction; Other: step-reduction plus resistance exercise

Interventions

step-reduction OTHER

reduce daily physical activity to less than 1500 steps per day

Isolated Whey Protein; Micellar Whey Protein; Micellar Whey Protein + Citrulline

step-reduction plus resistance exercise OTHER

reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Isolated Whey Protein; Micellar Whey Protein; Micellar Whey Protein + Citrulline

Eligibility Criteria

• Age: 65 Years - 80 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Older Adult (65+)

You may qualify if:

• Non-smoker

You may not qualify if:

• Health problems such as: heart disease, rheumatoid arthritis, diabetes, poor lung function, uncontrolled hypertension, or any health conditions that might put the participant at risk for this study
• Failed clearance for exercise participation by the participants family physician/medical doctor
• Failed an exercise strength test.
• Regular consumption of any analgesic or anti-inflammatory drug(s), prescription or non-prescription, chronically will be excluded.
• Taking any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
• Factors that may exclude a participant from an MRI scan (i.e. various implants, metal in the eyes etc)
• Participants who complete fewer than 5000 steps per day (as assessed by pedometer prior to the study).

Sponsors & Collaborators

• McMaster University: lead

Study Sites (1)

Exercise Metabolism Research Laboratory, McMaster Univeristy

Hamilton, Ontario, L8S 4K1, Canada

Location

Related Publications (2)

• Breen L, Stokes KA, Churchward-Venne TA, Moore DR, Baker SK, Smith K, Atherton PJ, Phillips SM. Two weeks of reduced activity decreases leg lean mass and induces "anabolic resistance" of myofibrillar protein synthesis in healthy elderly. J Clin Endocrinol Metab. 2013 Jun;98(6):2604-12. doi: 10.1210/jc.2013-1502. Epub 2013 Apr 15.

  PMID: 23589526 BACKGROUND

• Burd NA, West DW, Moore DR, Atherton PJ, Staples AW, Prior T, Tang JE, Rennie MJ, Baker SK, Phillips SM. Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men. J Nutr. 2011 Apr 1;141(4):568-73. doi: 10.3945/jn.110.135038. Epub 2011 Feb 2.

  PMID: 21289204 BACKGROUND

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 6, 2015
• First Posted: January 27, 2015
• Study Start: July 1, 2012
• Primary Completion: May 1, 2013
• Study Completion: May 1, 2013
• Last Updated: January 27, 2015

Record last verified: 2015-01

Locations

CA (1)