Muscle Protein Synthesis, Whole-body Protein Balance
Conditions
Brief summary
The amount of essential amino acids (EAA) necessary to maximally stimulate muscle protein synthesis and optimize whole-body net protein balance during caloric deprivation has not been determined. This study will address that gap in knowledge by examining the resting and post-exercise muscle and whole-body protein kinetic responses to ingesting varying amounts of EAA after a 5 day period of negative energy balance. This study will provide the initial evidence to support the development of a recovery-based food product for military combat rations.
Detailed description
Short-term negative energy balance downregulates muscle protein synthesis and upregulates whole-body proteolysis and amino acid (AA) oxidation, thereby increasing nitrogen excretion and exacerbating whole-body and skeletal muscle protein loss. Consumption of quality proteins high in essential amino acid (EAA) content may attenuate protein loss during energy deficit by restoring whole-body and skeletal muscle anabolic potential to that observed in a eucaloric state. During energy balance, muscle protein synthesis appears to be maximally stimulated after consuming 15 g of EAA at rest and after conventional resistance-type exercise. In response to a short-term energy deficit that downregulated basal muscle protein synthesis by as much as 27%, consuming 15 g (\ 7.5 g EAA) and 30 g (\ 15 g EAA) of whey protein after a bout of resistance exercise restored muscle protein synthesis rates to resting, fasted rates observed in the eucaloric state in a dose dependent manner. The effect of EAA intakes above 15 g on resting and post-exercise muscle protein synthesis and the whole-body protein anabolic response during acute energy deficit has not been determined. This study will assess resting and post-resistance exercise whole-body and skeletal muscle protein synthesis responses to across a spectrum of EAA intakes following a well-controlled, short-term (5-d) energy deficit (30% energy deficit). Using a randomized, double-blind, cross-over design, 20 resistance trained (≥ 2 d/wk for the past 6 mo) adults will undergo two, non-consecutive 5-d energy deficit periods, separated by a 14-d washout period. Resting and post-resistance exercise (single leg exercise model) whole-body protein turnover and skeletal muscle protein synthesis responses to two different doses of EAA (standard, 0.10 g/kg vs high, 0.30 g/kg) will be determined the morning after completing the 5-d energy deficit. This design will test the hypothesis that higher absolute doses of EAA are required to maintain resting and post-exercise anabolic responses during energy deficit.
Interventions
DIETARY_SUPPLEMENTStandard EAA
EAA provided relative to body mass at a standard dose (0.10 g/kg) during energy deprivation
DIETARY_SUPPLEMENTHigh EAA
EAA provided relative to body mass at a high dose (0.30 g/kg) during energy deprivation
Sponsors
University of Arkansas
Eastern Michigan University
United States Army Research Institute of Environmental Medicine
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Intervention model description
Randomized, double-blind, cross-over controlled trial
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Men and women aged 18 - 35 years * Body mass index \< 30.0 kg/m2 * Healthy without evidence of chronic illness or musculoskeletal injury as determined by the USARIEM Office of Medical Support and Oversight (OMSO) * Resistance exercise trained defined by self-report as performing ≥ 2 sessions/wk for previous 6 mo * Refrain from taking any nonsteroidal anti-inflammatory drugs (e.g., aspirin, Advil®, Aleve®, Naprosyn®), or any other aspirin-containing product for 10 days before starting and at least 5 days after completing the study * Willing to refrain from alcohol, smoking any nicotine product (includes e-cigarettes); vaping, chewing tobacco, caffeine, and dietary supplement use throughout the entire study period * Supervisor approval for federal civilian employees and non-HRV active duty military personnel working within the US Army Natick Soldier Systems Center
Exclusion criteria
* Musculoskeletal injuries that compromise exercise capability as determined by the USARIEM Office of Medical Support and Oversight (OMSO) * Metabolic or cardiovascular abnormalities, gastrointestinal disorders (e.g., kidney disease, diabetes, cardiovascular disease, etc.) * Abnormal PT/PTT test or problems with blood clotting * History of complications with lidocaine * Present condition of alcoholism, anabolic steroids, or other substance abuse issues * Blood donation within 8-wk of beginning the study * Pregnancy (self-report or results of urine pregnancy test before body composition testing) * Unwillingness or inability to consume study diets or foods provided
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial, Resting Muscle Protein Synthesis Rates | 3 hour measure of muscle protein synthesis | Assessed using stable isotope infusions of phenylalanine. |
| Postprandial, Post-exercise Muscle Protein Synthesis Rates | 3 hour measure of muscle protein synthesis | Assess using stable isotope infusions of phenylalanine. |
| How Well Participants Suppress the Degradation of Body Proteins While Stimulating the Growth of New Proteins After Ingesting Varying Doses of EAA at Rest and After Exercise. Net Whole-body Protein Balance | 3 hour measure of whole-body protein balance | Assessed using stable isotope infusions of tyrosine. Net Whole-body Protein Balance is defined as whole-body protein synthesis - whole-body protein breakdown) |
Countries
United States
Participant flow
Pre-assignment details
This was a cross-over design study. 19 volunteers completed both the standard and high EAA testing phases.
Participants by arm
| Arm | Count |
|---|---|
| All Study Participants All participants were randomized to receive all interventions. | 19 |
| Total | 19 |
Baseline characteristics
| Characteristic | All Study Participants |
|---|---|
| Age, Continuous | 23 years STANDARD_DEVIATION 5 |
| Body Mass Index | 25.4 kilograms per meter squared STANDARD_DEVIATION 2.7 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 18 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Sex: Female, Male Female | 0 Participants |
| Sex: Female, Male Male | 19 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 10 | 0 / 10 | 0 / 10 | 0 / 10 |
| other Total, other adverse events | 0 / 10 | 0 / 10 | 0 / 10 | 1 / 10 |
| serious Total, serious adverse events | 0 / 10 | 0 / 10 | 0 / 10 | 0 / 10 |
Outcome results
Primary
How Well Participants Suppress the Degradation of Body Proteins While Stimulating the Growth of New Proteins After Ingesting Varying Doses of EAA at Rest and After Exercise. Net Whole-body Protein Balance
Assessed using stable isotope infusions of tyrosine. Net Whole-body Protein Balance is defined as whole-body protein synthesis - whole-body protein breakdown)
Time frame: 3 hour measure of whole-body protein balance
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Standard EAA Dose | How Well Participants Suppress the Degradation of Body Proteins While Stimulating the Growth of New Proteins After Ingesting Varying Doses of EAA at Rest and After Exercise. Net Whole-body Protein Balance | 2.7 grams of protein per 180min | Standard Deviation 1.7 |
| High EAA Dose | How Well Participants Suppress the Degradation of Body Proteins While Stimulating the Growth of New Proteins After Ingesting Varying Doses of EAA at Rest and After Exercise. Net Whole-body Protein Balance | 21.3 grams of protein per 180min | Standard Deviation 3.4 |
Primary
Postprandial, Post-exercise Muscle Protein Synthesis Rates
Assess using stable isotope infusions of phenylalanine.
Time frame: 3 hour measure of muscle protein synthesis
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Standard EAA Dose | Postprandial, Post-exercise Muscle Protein Synthesis Rates | 0.055 percent per hour | Standard Deviation 0.01 |
| High EAA Dose | Postprandial, Post-exercise Muscle Protein Synthesis Rates | 0.065 percent per hour | Standard Deviation 0.02 |
Primary
Postprandial, Resting Muscle Protein Synthesis Rates
Assessed using stable isotope infusions of phenylalanine.
Time frame: 3 hour measure of muscle protein synthesis
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Standard EAA Dose | Postprandial, Resting Muscle Protein Synthesis Rates | 0.055 percent per hour | Standard Deviation 0.01 |
| High EAA Dose | Postprandial, Resting Muscle Protein Synthesis Rates | 0.061 percent per hour | Standard Deviation 0.02 |