Effect of Supplementing a Mixed Macronutrient Beverage With Graded Doses of Leucine on Myofibrillar Protein Synthesis

NCT01885429 | Completed

• 1 other identifier: 10.32.NRC
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

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 (whey), appears to be the amount of protein that maximizes the rate of muscle protein synthesis after performing a bout of resistance exercise. Thus, we aim to measure the synthesis of new muscle proteins after ingesting different amounts of protein and amino acids. We will measure muscle protein synthesis after consumption of the beverage a participant is randomized to in a leg that has done no exercise ( ie. a rested leg) and in the other leg that has done resistance exercise. 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. Leucine, isoleucine, and valine are simply 3 of the 8 essential amino acids that make up dietary protein. Unlike essential amino acids, 'non-essential' amino acids may be synthesized by the body, however they are also present in protein rich foods like chicken or milk. We aim to determine if it is the leucine content found in 25 g of whey protein that is primarily responsible for maximizing muscle protein synthesis at rest and following resistance exercise. We also wish to determine how muscle genes and metabolism respond to this protocol.

Conditions

Muscle Protein Synthesis

Keywords

Protein Turnover; Resistance Exercise; Whey Protein; Leucine

Outcome Measures

Primary Outcomes (1)

• Change from baseline in myofibrillar protein synthesis

  Myofibrillar protein synthesis will be determined by the standard precursor-product method as described previously and routinely measured and published.

  In the first 1.5h after exercise/feeding and from 1.5-4.5h after exercise/feeding

Study Arms (5)

Positive Control

EXPERIMENTAL

Group 1 (Positive(+) Control) will receive: 25g of whey protein. Positive Control

Dietary Supplement: Positive Control

Negative Control

EXPERIMENTAL

Group 2 (Negative(-) Control) will receive: 6.25g whey. Negative Control

Dietary Supplement: Negative Control

Low Protein + Low Leucine Spike

EXPERIMENTAL

Group 3 (Low Protein + Low Leucine Spike) will receive: 6.25g whey + low added leucine. Low Protein Low Leucine Spike

Dietary Supplement: Low Protein Low Leucine Spike

Low Protein + High Leucine Spike

EXPERIMENTAL

Group 4 (Low Protein + High Leucine Spike) will receive: 6.25g whey + high added leucine. Low Protein High Leucine Spike

Dietary Supplement: Low Protein High Leucine Spike

Low Protein + High Leucine + BCAA Spike

EXPERIMENTAL

Group 5 (Low Protein + High Leucine + BCAA Spike) will receive: 6.25g whey + added branched-chain amino acids. Low Protein + High Leucine + BCAA Spike

Dietary Supplement: Low Protein + High Leucine + BCAA Spike

Interventions

Positive Control DIETARY_SUPPLEMENT

Subject consumes 25g of whey protein following unilateral exercise

Positive Control

Negative Control DIETARY_SUPPLEMENT

Subject consumes 6.25g of whey protein following unilateral exercise

Negative Control

Low Protein Low Leucine Spike DIETARY_SUPPLEMENT

Subject consumes 6.25g of whey protein plus 3g of leucine following unilateral exercise

Low Protein + Low Leucine Spike

Low Protein High Leucine Spike DIETARY_SUPPLEMENT

Subject consumes 6.25g of whey protein plus 5g of leucine following unilateral exercise

Low Protein + High Leucine Spike

Low Protein + High Leucine + BCAA Spike DIETARY_SUPPLEMENT

Subject consumes 6.25g of whey protein plus 5g of leucine plus valine and isoleucine (BCAA) following unilateral exercise

Low Protein + High Leucine + BCAA Spike

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Male
• Healthy and physically active (as determined by medical and activity questionnaire)
• years of age
• kg body mass
• Having given informed consent

You may not qualify if:

• Exhibiting health risk factors as identified on the health screening questionnaire
• Having any identified metabolic or intestinal disorders
• Tobacco use
• Aspirin use in the 4 days prior to the experimental trial
• Consumption of prescription medications or any performance enhancing agent
• Inability to endure the strenuous exercise bouts e.g. injuries
• Alcohol intake during the 48 hours prior to each of the testing days
• Currently participating or having participated in another clinical trial during the last 4 weeks prior to the beginning of this study
• Have given blood in the last three weeks
• Verbal confirmation that they have used a substance on the WADA banned list within the last year

Sponsors & Collaborators

• McMaster University: lead

Study Sites (1)

McMaster University

Hamilton, Ontario, L8S 4K1, Canada

Location

MeSH Terms

Interventions

Diet, Protein-Restricted

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Stuart M Phillips, PhD

  McMaster University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 23, 2013
• First Posted: June 25, 2013
• Study Start: January 1, 2011
• Primary Completion: May 1, 2011
• Study Completion: May 1, 2011
• Last Updated: July 30, 2013

Record last verified: 2013-07

Locations

CA (1)