Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized...

27
Douglas Paddon-Jones, Ph.D. The University of Texas Medical Branch Dietary protein: guidelines, requirements and a lack of common sense

Transcript of Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized...

Page 1: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

Douglas Paddon-Jones, Ph.D.

The University of Texas Medical Branch

Dietary protein: guidelines, requirements

and a lack of common sense

Page 2: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

1. protein metabolism

2. building muscle in response to a protein-rich meal

3. translating science into practice

4. priority areas: aging - physical inactivity – hospitalization

5. negative consequences of extra protein?

6. sarcopenia and a new strategy

Overview

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Inactivity

Malnutrition

Balance

Synthesis

Breakdown

Muscle

growth

Muscle

loss

Nutrition

Exercise

Hormones

Maintaining Muscle Mass and Function

Illness/Injury

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Stimulating Muscle Growth with Protein

Symons et. al. AJCN, 2007

* *

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Fasting

Pro

tein

Synth

esis

(%

/h)

Young

Elderly

50% increase

30 g protein

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Protein Synthesis and Portion Control - a message of moderation -

* *

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Fasting 30 g protein

Pro

tein

Synth

esis

(%

/h) * *

Fasting 90 g protein

Young

Old

~1.2 g/kg/day for 180 lb individual

90 g protein 30 g protein

Symons et. al. AJCN, 2007 Symons et. al. JADA. 2009

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Ne

t M

uscle

Pro

tein

Syn

thesis

(mg

Ph

e/leg

)

More than ~25 g protein

Age-related protein dose-response

0

10

20

30

40

50

60

Young

Elderly

Less than ~15 g protein

Katsanos et. al. AJCN, 2005

5 g

8 g

6 g

6 g

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* *

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Fasting Protein meal

Pro

tein

Syn

thesis

(%

/h)

0.16

0.18

Young

Elderly

* *

Protein + Exercise

50% increase

100% increase

Synergistic Effect of Protein and Exercise

Symons et. al. JNHA, 2010

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Timing of Protein and Exercise

Meal Appearance in plasma Peak anabolic window

Whey Protein

Amino Acids 10-20 minutes Consume 0-60 minutes post exercise

Intact Proteins

(beef, fish etc.) 120+ minutes

Consume approx.. 90 minutes before

exercise

* note, the timing relates only to muscle protein anabolism and does not take

into account practical issues such as exercise performance, satiety, gastric

comfort, hunger or coingestion of other nutrients.

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Leucine Content of Foods

1 scoop (36 g) of whey protein isolate

3.2 g

1 scoop (36 g) soy protein isolate 2.4 g

4 oz. sirloin steak 2.0 g

4 oz. chicken breast 2.0 g

1 cup low-fat yogurt 1.1 g

1 cup fat-free milk 0.8 g

1 egg 0.5 g

2 tbsp. peanut butter 0.5 g

1 slice wheat bread 0.1 g

Sources: USDA National Nutrient Database for Standard Reference, Release 20. and GNC WPI 28

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Optimizing meal anabolism with Leucine

0

0.05

0.06

0.07

0.08

0.09

Post-absorptive

Post-prandial

Day 1 (pre)

0.10

0.11

0.12

Day 14

( 2 weeks LEU)

P=0.02

P=0.04

Pro

tein

synth

esis

: %

/ h

r

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Daily protein distribution - typical ? -

Total Protein

90 g

Cat

abol

ism

A

nab

olis

m

10 g

maximum rate of protein synthesis

15 g 65 g

A skewed daily protein distribution fails

to maximize potential for muscle growth

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Daily protein distribution - Optimal -

Cat

abol

ism

A

nab

olis

m

maximum rate of protein synthesis

30 g 30g 30 g

Total Protein

90 g

Repeated maximal stimulation of protein synthesis increase / maintenance of muscle mass

~ 1.3 g/kg/day

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Bed rest is a defacto treatment modality - if you’re hospitalized you become inactive -

Inactive

(0 steps/min)

Low Activity

(< 15 steps/min)

0

10

20

30

40

50

60

70

80

90

100

% of

Time

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Inactivity and Aging Muscle

-1500

-1000

-750

-500

-250

0

250

Lo

ss

of

lea

n l

eg

ma

ss

(g

)

-2000

Healthy Young

28 Days Inactivity

2%

total lean leg mass

Healthy Elders

10 Days Inactivity

10%

total lean leg mass

Paddon-Jones et. al. 2004

Kortebein et al. 2007

3 times more

muscle loss

1/3 the time

All volunteers

consumed the

RDA for protein

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Inactivity reduces muscle protein synthesis

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Day 1 Day 10

Pro

tein

Synth

esis

(%

/h)

* 30%

Kortebein et al. 2007

24 h muscle protein synthesis during 10 day of inactivity in elders

(stable isotope methodology)

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Protein combats inactivity-induced muscle loss

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Day 1 Day 10

Pro

tein

Synth

esis

(%

/h)

*

Normal Diet Normal Diet Normal Diet +

Amino Acids

#

Normal Diet +

Amino Acids

30%

Ferrando & Paddon-Jones et. al. 2009

- older adults -

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Are our older inpatients eating enough ?

0

20

40

60

80

100

Protein Carbohydrate Fat

Presented

Consumed

gra

ms

0

20

40

60

80

100

Protein Carbohydrate Fat

Presented

Consumed

gra

ms

per meal

Paddon-Jones, pilot data

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Muscle Loss in Hospitalized Elders

-1500

-1000

-750

-500

-250

0

250

Lo

ss o

f le

an

leg

mass (

g)

-2000

Healthy Young

28 Days Inactivity

2%

total lean leg mass

Healthy Elders

10 Days Inactivity

10%

total lean leg mass 10+ %

total lean leg mass

Elderly Inpatients

3 days hospitalization

Paddon-Jones , Pilot Data

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The Protein Myth

“Adults eat more protein than they need”

True: most adults eat more protein than the

minimum to prevent deficiencies

But: minimum needs ≠ optimum health

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Dietary protein and Bone… the myth

Increased protein causes calciuria and will ultimately weaken bone

Page 21: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

Dietary protein and Bone… the reality

Protein

Ca2+

[Ca2+]

+

• Moderate protein diets (1- 1.5 g/kg/day)

are associated with normal calcium

metabolism

• Low protein intakes ( 0.8 g/kg/day):

intestinal calcium absorption is reduced

and levels of parathyroid hormone

increase, causing the release of

calcium from bone Ca2+

Feskanich D, et al. Am J Epidemiol 1996;143:472-9. Cooper C, et al. Calcif Tissue Int 1996;58:320-25

Page 22: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

Institute of Medicine:

“protein content of diet is not related to progressive decline in kidney function with age."

Protein and Renal Function

Page 23: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

Sarcopenia: - traditional model -

20 30 40 50 60 70 80 5

10

15

20

25

30

35

Fat Mass

Age (years)

(kg)

20 30 40 50 60 70 80

30

35

40

45

50

55

Lean Body Mass

Age (years)

(kg)

Holloszy, Mayo Clin Proc. 2000

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Alternate model of muscle loss - developing tactical nutrition interventions -

15

17

19

21

23

25

27

29

31

40 44 48 52 56 60 64 68 72 76 80 84 88

Age (yrs)

Lean m

uscle

mass (

kg)

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Prevention and treatment strategies - muscle mass & function -

PREVENTION:

a). Consume a moderate amount of high-quality protein, 3-times per day

b). Consume protein in close proximity to physical activity

TREATMENT:

a). React aggressively with nutritional support to reduce the rapid loss of

muscle and strength associated with physical inactivity

Page 26: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

Benefits of exercise and high quality protein are not age dependent

Distribution of protein throughout the day is key

Moderation and common sense are still the key theme

Hypertrophy is slow, but atrophy can be exceedingly fast

The RDA for protein is not sufficient in many circumstances

Summary

25-30 g of protein maximally stimulates muscle protein synthesis

Page 27: Dietary protein: guidelines, requirements and a lack of ...€¦ · Muscle Loss in Hospitalized Elders -1500 -1000 -750 -500 -250 0 250 g)-2000 Healthy Young 28 Days Inactivity 2%

Madonna Mamerow, Ph.D.

Fellow

Joni Mettler, Ph.D.

Fellow

Kirk English

Doctoral Student

Christopher Danesi

Coordinator