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Dairy proteins andDairy proteins and Muscle Mass in Athletes and the Aged
David Cameron-SmithDavid CameronSchool of Exercise
Smith and Nutrition
Sciences Deakin University AUSTRALIA
1
Muscle Physiology and Function
• Largest tissue of the human body
• Responsible for the vast majority of energy use
• Primary site of glucose disposal, fat use and protein stores
• Major site of hormone action (insulin)
2
1
a
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Remarkable Capacity for Adult Regeneration
60
% f t Men Women
Declines with Age
-20
0
20
40 % fat
BMI
muscle mass
% fat
BMI
% d
iffer
ence
muscle
30 40 50 60 70 80 90
-60
-40
30 40 50 60 70 80 90
mass
Muller et al, 1994 Age(years)
mass
4
2
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An Ageing Nation
3
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25 year old man
Smaller, fattier and stiffer
65 year old man
7
8
4
@ DEAKIN UNIVERSITY AUSTRALIA
Bone
Teroon Muscle
@ DEAKIN UNIVERSITY AUSTRALIA
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Muscle Structure
9
10
Partridge T et al, 2005
5
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Muscle - Protein Balance
MUSCLE MASS
Synthesis Muscle growth
Nutrition
Exercise
Hormones
Malnutrition
Breakdown Insulin
resistance
Inactivity Muscle
loss
Malnutrition
11
Muscle Loss in Elderly
12
6
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Hormones
13
Exercise Activation of Protein Synthesis
Rasmussen BB et al. J. Appl. Physiol. 88:386-92, 2000
14
7
RR-
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Strength Gains in Nonagenarians
15
20
25
30
M (K
g)M
(Kg) 19.3
BASELINEBASELINE WEEK 8WEEK 8 0
5
1011-RR
7.6
Fiatarone et al JAMA 1990;263:3029 15
16
8
10
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Just 7 grams – of essentials ONLY
20
30
40
50
n in
Mus
cle P
rote
in
-10
0
10
EAAs + NEAAs EAAs NEAAs
Net G
ain
Volpi, et al. Am J Clin Nutr 78:250-258, 2003
Katsanos, et al. Nutr Res 28:651-658, 2008
30 Diminished response in elderly
20
30
*
g Ph
/ Leg
30
20
0
10
Young Elderly
mg
10
0
Katanos et al Am J Clin Nutr. 2005 Nov;82(5):1065-73
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10
LEUCINEPROTEIN SOURCE
14%Whey protein isolate 26%
BCAA
10%Milk protein
8.5%Egg protein
8%Muscle protein
14%Whey protein isolate
18%
20%
21%
26%
15%
18%
19
7%Wheat protein
8%Soy protein isolate
8%Muscle protein
Whey - Rapid Digestion
Franfield MM et al. Int J Food Sci Nutr. 2008: 8-11. 20
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Superiority of Whey
Katsanos et al. Nutr Res. 2008 October ; 28(10): 651–658. 21
Compared to other protein sources
22Tang et al J Appl Physiol 107: 987-992, 2009
11
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More evidence of superiority – the signals
http://cellbio.utmb.edu/cellbio/rer4.jpg
Whey V Soy – Older men 50 ***
10
20
30
40
50 Placebo CHO 30g Soy 30g W hey
*** ***
***
A
A
B B
A A A
B
p-p7
0S6K
(Thr
389)
Fold
Cha
nge
Pre 2hr Post 4hr Post 0
* p
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How much?
20 25 30 35 40 45 50 55
Placebo 10g 20g 30g 40g
*
**
***
p
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Exercise and Whey Protein in Older People
27
Acknowledgements
14
