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

Older Adults Clinical Trial

Official title:

Efficacy of Isolated Whey and Micellar Whey Protein (+/-Citrulline) to Stimulate Protein Synthesis in 'Healthy' and 'Anabolically Resistant' Elderly Muscle

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02347137
• Other study ID #: 11-267
• Status: Completed
• Phase: N/A
• First received: January 6, 2015
• Last updated: January 21, 2015
• Start date: July 2012
• Est. completion date: May 2013

Study information

• Verified date: January 2015
• Source: McMaster University
• Contact: n/a
• Is FDA regulated: No
• Health authority: Canada: Institutional Review Board
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30
• Est. completion date: May 2013
• Est. primary completion date: May 2013
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 65 Years to 80 Years

Eligibility

Inclusion Criteria:

• Non-smoker

Exclusion Criteria:

• 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).

Study Design

Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

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

Intervention

Other:
• step-reduction
reduce daily physical activity to less than 1500 steps per day
• step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Locations

Country	Name	City	State
Canada	Exercise Metabolism Research Laboratory, McMaster Univeristy	Hamilton	Ontario

Sponsors (1)

Lead Sponsor	Collaborator
McMaster University

Country where clinical trial is conducted

Canada, 

References & 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. — View Citation

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Myofibrillar fractional synthetic rate will be measured using 13C6 ring phenylalanine	analysis	7 hours	No
Secondary	body composition (lean body mass, fat mass, leg lean mass, leg fat mass) will be measured using dual energy xray absorptiometry	analysis	14 days	No
Secondary	leg muscle strength (leg press and leg extension 1 repetition maximum [1-RM], peak knee extensor torque) will be measured using a dynamometer	analysis	14 days	No
Secondary	vascular function (femoral blood flow, femoral artery diameter, leg pulse) will be measured using doppler ultrasound	analysis	14 days	No