Dietary Strategies to Promote Muscle Protein Anabolism in the Elderly

Sponsor

Maastricht University Medical Center (Other)

Overall Status

Completed

CT.gov ID

NCT00557388

Collaborator

National Nutrition and Food Technology Institute (Other)

120

Enrollment

Location

Arms

Duration (Months)

3.4

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Aging is associated with the loss of lean muscle mass, termed sarcopenia. Food intake and in particular the ingestion of protein or amino acids has been shown to be a powerful stimulus to promote net muscle protein anabolism. However this anabolic response following a meal-like protein bolus seems to be blunted in the elderly as compared to young adults.

The first aim of this proposal is to investigate the post-prandial muscle protein synthesis rates in young and elderly men in response to a meal-like protein bolus after a period of rest or physical activity (study A). The rest trial (REST) will act as a proof-of-principle study to examine the blunted protein synthetic response in the elderly, and as a control trial in comparison with the exercise trial (EXC) to establish the surplus value of physical activity prior to protein intake on muscle protein synthesis.

The second aim of this proposal is to determine the surplus value of an increased quantity of the ingested protein bolus (study B). Large amounts of protein (40 and 60 g) will be compared to a meal-like amount of protein (20 g) as a means to maximize plasma amino acid availability and/or to stimulate muscle protein anabolism.

The third aim of this proposal is to study the differences in quality of the ingested protein bolus (study C). Instead of significantly increasing the quantity of the protein bolus, we will also apply a more practical approach to augment skeletal muscle protein synthesis rates; modifying the digestibility or amino acid composition of a meal-like protein bolus.

Condition or Disease	Intervention/Treatment	Phase
Sarcopenia	Dietary Supplement: Protein/Amino Acids Other: Physical exercise	N/A

Study Design

Study Type:

Interventional

Actual Enrollment :

120 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Participant, Outcomes Assessor)

Primary Purpose:

Prevention

Official Title:

Dietary Strategies to Promote Muscle Protein Anabolism in the Elderly

Study Start Date :

Dec 1, 2007

Actual Primary Completion Date :

Nov 1, 2010

Actual Study Completion Date :

Nov 1, 2010

Arms and Interventions

Arm	Intervention/Treatment
Experimental: 1 Young men 18-30 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine Other: Physical exercise The physical exercise protocol will consist of low intensity cycling and light resistance-type exercise; after 5 minutes of self-paced cycling, subjects will perform 6 sets of 10 repetitions on the horizontal leg press machine (Technogym BV, Rotterdam, The Netherlands) and 6 sets of 10 repetitions on the leg extension machine (Technogym BV, Rotterdam, The Netherlands). The first 2 sets of both resistance exercises will be performed at 40% of the subjects' 1RM. Sets 3-4, and 5-6 will be performed at 55% and 75% of 1RM, respectively, with 2 minutes rest intervals between sets.
Experimental: 2 Young men 18-30 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 3 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine Other: Physical exercise The physical exercise protocol will consist of low intensity cycling and light resistance-type exercise; after 5 minutes of self-paced cycling, subjects will perform 6 sets of 10 repetitions on the horizontal leg press machine (Technogym BV, Rotterdam, The Netherlands) and 6 sets of 10 repetitions on the leg extension machine (Technogym BV, Rotterdam, The Netherlands). The first 2 sets of both resistance exercises will be performed at 40% of the subjects' 1RM. Sets 3-4, and 5-6 will be performed at 55% and 75% of 1RM, respectively, with 2 minutes rest intervals between sets.
Experimental: 4 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 5 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 6 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 7 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 8 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 9 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine
Experimental: 10 Old men 70-85 years, BMI < 27 kg/m2	Dietary Supplement: Protein/Amino Acids Casein Whey Leucine

Outcome Measures

Primary Outcome Measures

All interventions will affect muscle protein synthesis. With the application of amino acid tracer methodology we are able to determine muscle protein synthesis. [6 hours]

Secondary Outcome Measures

Differences in rate of uptake/absorption from the intestine. [6 hours]

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 85 Years

Sexes Eligible for Study:

Male

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

In study A, non-obese male subjects (BMI <27) between the age of 18-30 yrs and 70-85 yrs will be selected.
In studies B and C, non-obese male subjects (BMI <27) between the age of 70-85 yrs will be selected.