Role of Leucine in the Regulation of Human Myofibrillar Protein Synthesis at Rest and Following Resistance Exercise

NCT ID: NCT01492010

Last Updated: 2020-02-24

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 24 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2010-06-30
• Study Completion Date: 2010-09-30

Brief Summary

Muscle mass is normally maintained through the regulated balance between the processes of protein synthesis (i.e. making new muscle proteins) and protein breakdown (breaking down old muscle proteins). Proteins are composed of amino acids and we know that amino acids increase muscle protein synthesis. However, not all amino acids are the same. Essential amino acids are ones that must be consumed through food, while non-essential amino acids can be made by our body. Interestingly, the essential amino acids are all that are required to increase the rate of muscle protein synthesis. In addition, the essential amino acid leucine appears to be particularly important in regulating protein synthesis. However, how leucine is able to increase protein synthesis is not entirely understood. Previously, it has been shown that 20-25 g of high-quality protein, such as that found in milk, appears to be the amount of protein that maximizes the rate of muscle protein synthesis after performing a bout of resistance exercise. Thus, the aim is to measure the synthesis of new muscle proteins after ingesting the following:

1. 25g whey protein

2. 6.25g whey protein supplemented with leucine

3. 6.25g whey protein supplemented with essential amino acids but no leucine

The investigators will measure muscle protein synthesis after consumption of the above beverages in a leg that has done no exercise ( ie. a rested leg) and in the other leg that has done resistance exercise. The hypothesis is that 6.25g whey supplemented with leucine will stimulate muscle protein synthesis as effectively as 25g whey, but that 6.25g whey supplemented will all the essential amino acids except whey will be less effective at increasing muscle protein synthesis. Whey protein is a dairy-based protein found in cow's milk, thus when you drink a glass of milk you are consuming some whey protein. However, the investigators will be using an isolated form of whey protein, meaning it has been removed from milk. As mentioned previously, amino acids are 'strung-together' to make protein. The 'essential' amino acids must be consumed through food because our body cannot make them, thus they are consumed when you eat protein-rich foods like milk or chicken.

Conditions

Regulation of Muscle Protein Synthesis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

25 g protein

25 g whey protein

Group Type: EXPERIMENTAL

whey protein

Intervention Type: DIETARY_SUPPLEMENT

25 g whey protein

6.25 g protein supplemented with leucine

6.25 g protein supplemented with leucine

Group Type: EXPERIMENTAL

whey protein supplemented with leucine

Intervention Type: DIETARY_SUPPLEMENT

6.25 g whey protein supplemented with free form leucine

6.25 g whey protein with EAA

6.25 g protein supplemented with a mixture of essential amino acids devoid of leucine

Group Type: EXPERIMENTAL

whey protein supplemented with essential amino acids

Intervention Type: DIETARY_SUPPLEMENT

6.25 g whey protein supplemented with essential amino acids devoid of leucine

Interventions

whey protein

25 g whey protein

Intervention Type: DIETARY_SUPPLEMENT

whey protein supplemented with leucine

6.25 g whey protein supplemented with free form leucine

Intervention Type: DIETARY_SUPPLEMENT

whey protein supplemented with essential amino acids

6.25 g whey protein supplemented with essential amino acids devoid of leucine

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

whey protein powder; whey protein powder supplemented with free-form leucine; whey protein supplemented with EAA devoid of leucine

Eligibility Criteria

Inclusion Criteria

• male
• 18-35 years of age
• non-smoker/ non-tobacco product user

Exclusion Criteria

• heart disease
• vascular disease
• rheumatoid arthritis
• diabetes
• poor lung function
• uncontrolled blood pressure
• dizziness
• thyroid problems

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of California, Davis

OTHER

Sponsor Role: collaborator

Canadian Institutes of Health Research (CIHR)

OTHER_GOV

Sponsor Role: collaborator

Natural Sciences and Engineering Research Council, Canada

OTHER

Sponsor Role: collaborator

McMaster University

OTHER

Sponsor Role: lead

Responsible Party

Stuart Phillips

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Stuart M Phillips, PhD

Role: PRINCIPAL_INVESTIGATOR

McMaster University

Locations

Exercise Metabolism Research Laboratory, McMaster Univeristy

Hamilton, Ontario, Canada

Countries

Canada

References

Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012 Jun 1;590(11):2751-65. doi: 10.1113/jphysiol.2012.228833. Epub 2012 Mar 25.

Reference Type: DERIVED

PMID: 22451437 (View on PubMed)

Other Identifiers

LEU-10-141

Identifier Type: -

Identifier Source: org_study_id