Download The Role of Protein in Promoting Muscle Growth Presentation

5/26/13
The Role of Protein in Promoting
Muscle Growth
Blake B. Rasmussen, PhD
Professor & Chair
Department of Nutrition & Metabolism
University of Texas Medical Branch
Department of Nutrition & Metabolism
Presentation Outline
•  Building Muscle - Why is it Important?
•  Role of Protein Synthesis
•  Effect of Resistance Exercise on Protein Synthesis
•  Effect of Dietary Protein on Protein Synthesis
•  Protein Supplementation and Exercise Training
•  What Protein Source is Best?
•  Timing of Protein Supplementation?
•  How Much Protein Should Athletes Consume?
•  Summary & Recommendations
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Why Study Muscle Biology?
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Muscle Wasting Conditions
" 
Injury
" 
Following Surgery
" 
Elderly (Sarcopenia)
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Forced Inactivity / Bed Rest
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Cancer, AIDS, Space Flight, Muscular Dystrophy
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Trauma, Burns, Type 1 Diabetes
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Sports Nutrition - Protein
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Building Muscle
Muscle Growth
Muscle Atrophy
Protein Synthesis
Protein Degradation
Exercise
Feeding
Unloading
Starvation
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The Muscle Biopsy
Bergström, 1962
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Role of Protein Synthesis
Muscle Cell
Proteins
Synthesis
Breakdown
Blood
Net Protein Balance = Synthesis - Breakdown
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m
TORC1 Signaling
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Effect of Resistance Exercise on
Muscle Protein Synthesis
Exercise
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Resistance Exercise Increases
Muscle Protein Synthesis
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mTORC1 Activation
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Is mTORC1 Activation Required for Muscle
Contraction to Increase
Muscle Protein Synthesis?
Rapamycin
mTORC1
Muscle Protein Synthesis
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Yes! - mTORC1 is Required to Increase
Muscle Protein Synthesis
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Effect of Dietary Protein on
Muscle Protein Synthesis
Leucine
Essential Amino Acids
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Response to Essential
Amino Acids
mTOR Activation
mTOR (Ser2448)
(AU)
Muscle Protein Synthesis
(%⋅hr-1)
Muscle Protein Synthesis
Control
Control
Nutrition
Nutrition
Adapted from Fujita et al. J Physiol, 2007
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EAA is Responsible
for the Stimulation
of Muscle Protein
Synthesis
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Gln
Na+
Insulin
BCAA
Gln
K+
?
?
Rag
GTPases
raptor
mTORC
1
Rab?
MAP4K3
?
mTORC
1
?
?
Akt
PAT1
raptor
4E-BP1
Rheb
Rapamycin
S6K1
hVps34
eIF4F
Protein
Synthesis
rpS6
Translation Initiation
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Protein / Amino Acids Activate mTORC1 to
Increase Muscle Protein Synthesis
Muscle Protein Synthesis
(%⋅hr-1)
*
Basal
#
Post EAA
vs. Basal
*#
P<0.05
P<0.05 vs. Rapamycin
Dickinson et al, Journal of Nutrition, 2011!
Dickinson et al, Metabolism, 2012!
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Stimulating Muscle Growth
with Protein
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Muscle Protein Synthesis
(%•hr-1)
Exercise Enhances the Nutrition-Induced
Increase in Protein Synthesis
↑ ~50%
Young
RE = Resistance Exercise
↑ ~100%
↑ ~100%
Older
Adapted from Fry et al., Skeletal Muscle, 2011; & Drummond et al. J Appl Physiol, 2008
EAA = Essential Amino Acids
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Effect of Protein + Exercise
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Summary
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" 
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Resistance Exercise & Protein both stimulate muscle
protein synthesis primarily through mTORC1
activation
mTORC1 should be considered a target when
designing nutritional supplements to enhance muscle
growth
Consuming Protein After Exercise Enhances Muscle
Protein Synthesis
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Protein Supplementation During
Exercise Training
Does it Enhance Muscle Growth?
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Protein Supplementation
and Exercise Training
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Whey and Soy Protein
Supplementation Improves
Muscle Mass
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Milk vs Soy Supplementation
During Training
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What Protein Source is Best?
Must Consider Protein Quality
Which Means a Sufficient Amount of Essential Amino Acids
Especially Leucine
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Why is Whey Considered the
Gold Standard?
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Whey vs Soy: Effects on Muscle
Protein Synthesis
Fasting
N=6 per group
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Comparing Apples to Oranges?
20 grams = 1.9 g leucine 20 grams = 1.5 g leucine 27 grams = 1.9 g leucine Department of Nutrition & Metabolism
Protein Blends
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The Theory
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Journal of Nutrition 143: 410-416, 2013 Department of Nutrition & Metabolism
Study Aim
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Subjects
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Methods
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Methods
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Results
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Leucine
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Area Under The Curve
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Mixed Muscle Protein Synthesis
Whey
Blend
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mTORC1 Signaling
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Conclusions
A soy-dairy protein blend ingested following exercise is
capable of prolonging in human skeletal muscle:
• blood aminoacidemia
• mTORC1 signaling
• protein synthesis
Protein blends are an effective postexercise nutritional
supplement
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When Should an Athlete
Supplement with Protein?
Is Timing Important?
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EAA Ingestion 1 or 3 hours After Exercise
Produces the Same Response in Muscle
Protein Synthesis
Rasmussen et al, J Appl Physiol 88: 386-392, 2000
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Ingesting EAA Before Exercise Has No
Additional Benefit on Muscle
Protein Synthesis
Fujita et al, J Appl Physiol 106: 1730-1739, 2009
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After Exercise is Best
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Muscle Remains Sensitive to Protein For At
Least 24 Hours After Exercise
Burd et al, Journal of Nutrition 141: 568-573, 2011
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How Much Protein Does it Take to
Maximize Muscle
Protein Synthesis?
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Dose-Response Study
Cuthbertson et al, FASEB J., 2005
10 grams of EAA or ~20-25 grams of Protein
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30-30-30
A. Adequate Protein Distribution
B. Inadequate Protein Distribution
Maximal
Protein
Synthesis
Breakfast
Lunch
Dinner
Breakfast
~30 g
~30 g
~30 g
~10 g
Lunch
~20 g
Dinner
~60 g
protein
protein
protein
protein
protein
protein
Paddon-Jones & Rasmussen, Current Opinion in Clinical Nutrition & Metabolic Care, 2009
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Concept of Protein Distribution
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24 Hour Protein Synthesis
Preliminary data from D. Paddon-Jones
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Bolus = 40 g x 2 Intermediate = 20 g x 4
Pulse = 10 g x 8
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Summary
Exercise and Protein Both Increase Muscle Protein
Synthesis by Activating the mTORC1 pathway
Ingesting Protein After Exercise is Best for
Enhancing Muscle Protein Synthesis
Protein Supplementation During Exercise Training
can Enhance Muscle Growth
High Quality Protein Sources Produce Similar
Increases in Muscle Protein Synthesis and Muscle
Growth During Exercise Training
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Summary (cont.)
Best to Eat Protein After Exercise but Muscle
Remains Sensitive for at Least 24 hours post-ex
Ingesting a Large Amount of Protein is not
Necessary for Maximizing Muscle Protein
Synthesis
Distributing Protein Intake Evenly and Moderately
Throughout the Day is Likely to Improve Muscle
Growth During Training
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Recommendations
Use a High Quality Protein Source to Supplement
within the First Hour Post-Exercise.
Eat a Sufficient Amount of High Quality Protein at
Each Meal - Distributed Evenly Throughout the Day.
20-30 grams for Most Athletes. More for Larger
Athletes?
Moderation is the Key - Avoid Excessive Protein
Intake.
Practical Example Considering Glycogen
Replenishment
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Acknowledgments
Univ of Utah
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Acknowledgments
Univ Kentucky
Arizona State
Texas A&M
Univ Wisconsin
Paul Reidy
PhD Student
Elena Volpi, MD, PhD
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Funding
NIAMS R01 AR049877
NIA P30 AG024832
NICHD T32 HD007539
Solae, LLC
[email protected]
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