Får vi for lidt protein ?
Fra Overlevelse til Sundhed
Arne Astrup,
Head, professor, MD, Dr.Med.Sci.
Department of Human Nutrition,
University of Copenhagen
Conclusions from protein Summit,
Charleston May 2007
There is adequate rationale to revisit protein intake
recommendations and explore increasing the RDA. The
recent DRI macronutrient report and Dietary Guidelines
for Americans retained recommendations for minimum
protein intakes on the basis of nitrogen balance. This
approach is controversial and recognized by the National
Academy of Science to have substantial practical
limitations and problems. Thus, other methods and
endpoints to define protein requirements should be
considered.
Conclusions from protein Summit,
Charleston May 2007
Endpoints including muscle mass, strength and metabolic function in
relation to protein intake within the context of meeting other
nutrients in the diet should be integrated into studies designed to
determine dietary guidelines. The minimal amount of protein to avoid
a progressive loss of muscle is likely to be well below the optimal level
to maximize all aspects of muscle. Measures of body composition to
assess muscle mass; determination of insulin sensitivity from oralglucose-tolerance curves to assess metabolic function of muscle; and
dietary protein intake as an indicator of nutritional status are
methods that should be validated and used in large epidemiological
studies.
Conclusions from protein Summit,
Charleston May 2007
• Beneficial effects of protein intake above the
current RDA recommendations include weight
management, management/prevention of
diabetes/insulin resistance, lipid control and the
prevention of osteoporosis.
• Sarcopenia is a public health issue that will affect
an increasingly significant proportion of the
population in the near future. Consumption of
adequate protein is an important factor in its
prevention and/or treatment.
• Lean muscle mass builds strength and promotes
active daily life and may ultimately improve overall
health.
Conclusions from protein Summit,
Charleston May 2007
• Potential issues with high protein intake
involve bone health, kidney stones, urea
production among other conditions. The
implication of dietary protein as a
causative in these conditions is not
definitively supported by scientific
reports to date.
Weight Management—facts and stats
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•
•
•
Role of protein in satiety
Role of muscle mass in obesity
prevention
Thermogenic effect of protein
High-protein diets and weight loss
and regain
Definition of “high-protein”
inconsistent in studies; examples
High-protein diets and renal function.
Energy Balance Equation
Energy Stores = Energy Intake - Energy Expenditure
1% difference over 1 year
ENERGY
INTAKE
Intake = 1,000,000 kcal
ENERGY
EXPENDITURE
Expenditure 990,000 kcal
Weight Gain = 1.2 - 1.7 kg
Components of Daily Energy Expenditure
25
0
SMR BMR
Double Labelled Water
50
Respiratory Chamber
75
NEAT &
Unrestricted
Activity
SPA
Thermic effect of
food
Arousal
Ventilated Hood
% of Daily Energy Expenditure
100
Methods
Measurement of energy expenditure: Respiration chamber
Energy expenditure (energy
requirements) of normal weight,
overweight and obese subjects
4000
24-hour energy expenditure
(kcal/day)
Moderate activity level
Normal weight
Obesity
3000
Low activity level
Underreporting
bias
2000
Self-reported energy intake
1000
40
50
60
70
80
90
100 110 120
Body weight (kg)
Astrup, Clin. Endocrinol. Metab. 13: 1999, 109-120
Percentage of Explained Variance
Variability in Resting Metabolic Rate
Within
Subject
90
T3, NA, UCP
Family
80
0
Method
FFM
FM
Age
Sex
R2
235 kvinder og 78 mænd målt i respirationskammer på
FHE ved forskellige forsøg.
Å61
Relation between fat-free mass (FFM) and 24-h energy expenditure (EE) adjusted for
differences in duration of exercise and spontaneious physical activity
Klausen et al. Am J Clin Nutr 1997;65:895-907
Relation between fat mass (FM) and 24-h energy expenditure (EE) adjusted for
differences in duration of exercise, spontaneious physical activity and FFM
Klausen et al. Am J Clin Nutr 1997;65:895-907
Recommended Nutrient Content of a
Weight-Reducing Diet
Protein
15%
Carbohydrate
>55%
8%-10% Saturated fatty
acids
Fat
<30%
<10% Polyunsaturated
fatty acids
<15%
Monounsaturated
fatty acids
Calories: 500-1000 kcal/d reduction
Cholesterol: <300 mg/d
Fiber: 20-30 g/d
Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and
Obesity in Adults– The Evidence Report. Obes Res. 1998;6 (suppl 2).
Proposed Hierarchy of Satiety
Protein
leucine
fructose
Carbohydrate
fiber
mct
sucrose
Fat
Need hypothesis-driven studies to determine differences
Effect on satiety –
How satisfied do you feel?
I cannot eat another bite
Visual analogue scale (cm)
10
9
8
7
6
5
4
High-Protein meals
3
Normal protein meals
2
1
I am completely empty
0
8
10
12
14
16
18
Time
20
22
24
Highly satiating effect of protein
Animal model:
•Bensaid et al., Phys & Behav, 2002. Protein is more potent
than carbohydrate for reducing appetite in rats.
•Bensaid et al., Phys & Behav, 2003. A high-protein diet
enhances satiety without conditioned taste aversion in the rat.
•
•
Humans:
Latner & Schwartz, Appetite, 1999. The effects of a highcarbohydrate, high protein or balanced lunch upon later food
intake and hunger ratings.
Westerterp-Plantenga et al., AJCN, 1999. The appetizing
effect of anaperitif in overweight and normal-weight humans.
fat diets measured in a respiration chamber.
Measurementof energy expenditure:
Respiration chamber
Measurementof energy expenditure:
Respiration chamber
Thermogenic effect of protein
Thermogenic effect of protein vs.
carbohydrate
Identical parameters
- Energy (to energy balance = 0)
- Fat (30 energy-%)
Intervention parameters
- Protein vs Carbohydrate: 30 vs 10 protein-E%
- PORK vs SOY: 20 E% pork vs 20 E% soy protein
Mikkelsen et al. Am J Clin Nutr
2000;72:1135-41
Results
24 hour energy expenditure
PORK:
13.11 ± 1.00 MJ/da
(3.9%)
SOY:
12.86 ± 0.98 MJ/db
(1.9%)
CARBO:
12.62 ± 0.98 MJ/dc
BASELINE: 12.52 ± 1.06 MJ/db,c
Pork versus Soy: 1.9 % (P < 0.05)
Mikkelsen et al. Am J Clin Nutr 2000;72:1135-41
Intervention studies:
Does the effects of protein on
appetite and energy expenditure
translate into weight loss ?
METHODS
Subjects: 50 overweight and obese (25 in control group)
men (n=12) and women (n=38)
age: 19-55 years
BMI: 26-34 kg/m2
Free from illness (CVD, T2D etc.)
One-year randomised dietary intervention, comparing an ad libitum fat-reduced
diet (30% of energy) either
high in protein (25% of energy, HP) or
medium in protein (12% of energy, MP)
Normal fat control group (only 6 months)
DIETARY INTERVENTION
SUPERMARKET
DIETARY
MODEL
COUNSELLING
0
6
FREE LIVING
12
24
MONTH
Anthropometry, DEXA & Blood samples
Diet Registration
Compliance Assessment
Body weight
Protein versus Carbohydrate
SHOP
MODEL:
6 months with all food provided for free
Skov et al. Int. J. Obes 1999;23:528-536
Skov et al. Int. J. Obes 1999;23:528-536
COMPLIANCE 24-h Urinary Nitrogen
Medium-protein
High-protein
(n=23)
18
16
(n=23)
24-h UN (g)
14
12
10
(n=22)
(n=18)
8
6
0
1
2
3
4
5
6
7
8
9
10
11
12
Duration (month)
Due A et al. Int J Obes 2004;28:1283-90.
DROP OUT RATE
Month 0-6 (Free provision of food):
2 subjects dropped out in each group (NS)
Month 6-12 (dietary counseling):
7 (28%) in the MP group dropped out
2 (8%) in the HP group dropped out
(p=0.07)
Month 24 (follow up):
19 (76%) in the MP group and
14 (56%) in the HP group no longer attended (NS)
Due A et al. Int J Obes 2004;28:1283-90.
A randomized 6-month trial on
two fat-reduced diets:
Low protein versus high protein
Weight loss and fat loss
Skov et al. Int. J. Obes 1999;23:528-536
A randomized 12-month trial on
Low protein versus high protein
LP seca
HP seca
C seca
LP dxa
HP dxa
C dxa
90
Body
weight
(kg)
80
0
0
10
20
Dietary intervention
30
40
Follow-up
50
60
70
80
90
100
110
Weight maintenance
Duration (weeks)
Skov AR et al. Int J Obes 2002; 23: 528-36
Proportion of subjects having lost and maintained >5 and 10 kg body weight after 6, 12
and 24 months of dietary intervention.
CHANGES IN WAIST
6
12
0
-2
Medium-protein
(cm)
-4
High-protein
-6
-8
-10
-12
P=0.004
P=0.0006
Due A et al. Int J Obes 2004;28:1283-90.
CHANGES IN INTRA-ABDOMINAL FAT
6
12
0
(cm²)
-5
-10
Medium-protein
-15
High-protein
-20
-25
P=0.03
-30
-35
-40
P=0.002
Due A et al. Int J Obes 2004;28:1283-90.
Due A et al. Diabetes, Obesity and Metabolism, 2005, 7, 223-9.
Mean total plasma homocysteine at baseline and after 3 and 6 mo of the
intervention1
Low-protein group
(n = 23)
High-protein group
(n = 23)
Control group
(n = 14)
µmol/L
Baseline
10.9 ± 1.5
12.1 ± 2.3
10.8 ± 1.4
3 mo
10.6 ± 0.7
9.7 ± 0.7
9.8 ± 1.0
6 mo
10.4 ± 0.8
9.6 ± 0.7
10.3 ± 1.0
1x
± SEM. There were no significant differences between groups by ANOVA.
Haulrik N, Toubro S, Dyerberg J, Stender S, Skov AR, Astrup A.
Am J Clin Nutr 2002;76:1202-6.
A randomized 12-month trial on
Low protein versus high protein
Skov AR, Toubro S, Bülow J, Krabbe K, Parving HH, Astrup
A. Int J Obes 1999;23:1170-1177.
A randomized 12-month trial on
Low protein versus high protein
Skov AR, Toubro S, Bülow J, Krabbe K, Parving HH, Astrup
A. Int J Obes 1999;23:1170-1177.
A randomized 12-month trial on
Low protein versus high protein: BMC
3
6
Duration of dietary intervention (months)
Skov AR, Haulrik N, Toubro S, Mølgaard C, Astrup A. Obes. Res. 2002;10:432-8.
CONCLUSION
• A fat-reduced diet high in protein (25
E%)
• Is superior to a similar fat-reduced
high-carbohydrate diet over 12
months to reduce body fat (-4.6 vs 3.1 kg) and intra-abdominal fat mass.
• The high-protein diet did not have any
adverse effect on risk factors of
cardiovascular disease, osteoporosis,
or renal function
Protein power
Low Carbohydrate vs Low Fat
(Completers analysis)
Weight Loss (%)
0
Low-Fat
-5
Low Carb
-10
-15
0
Foster et al NEJM 2003;
3
6
Months of Diet
9
12
RDI: At least 130 g carbohydrate/day
Atkits: 50 g/d
Adverse effects: Muscle cramps, headache, weakness, diarheea etc.
No need to reduce carbohydrate intake that dramatic
Astrup, Larsen, Harper. The Lancet. 2004; 364: 897-9.
Institute of Medicine, USA
Despite the association between red meat
and certain tumor types, no clear role
for protein (in cancer) has yet emerged
The current state of the literature,
therefore, does not permit any
recommendations of upper limit to be
made on the basis of cancer risk
US recommendations
AMDR (DRI, Institute of Medicine, USA)
Protein:
Adults: 10-35%
Older children: 10-30%
Smaller children: 10-20 %
Institute of Medicine, USA
There is no evidence to suggest that the AMDR for
protein should be at levels below the RDA for protein
(~10 E%) for adults
There is insufficient data to suggest an upper limit for
an AMDR for protein
To complement the AMDR for fat (20-35 E%), and
carbohydrate (45-65E%) for adults, protein intakes
may range from 10-35E% to ensure a nutritionally
adequate diet
Discussion Points—questions that
remain to be answered
• Optimal protein (%) for weight control
and inproved CV and T2D risks
• Protein sources
• Adverse effects (renal, bone, but more
important cancer risk (BW vs. direct,
dairy/red meat)
• Mechanism behind
satiety/thermogenesis
Diet, Obesity and Genes
European Commission 6th framework: Food Quality & Safety
Coordinator: Wim Saris (NUTRIM, Maastricht)
RTD Line 1: Dietary Intervention
Budget: 3.7 mio. €
Dietary Intervention in whole families
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•
Ad libitum diet most effective against weight (re)gain
Long-term (6/12 mo) large-scale intervention study (700 adults
randomised plus 350-1050 children – 1-3 children/family)
Factorial Design (5 groups):
Low GI
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High/low Glycaemic Index
High/normal Protein
Control
High GI
Normal protein
1
2
High protein
3
4
Control
5
Disclosures
A receive honoraria for consulting and speakers fee
from several food companies
I sit in several advisory boards for food and weight
control companies
My department and research group receive funding
from >100 food companies
My university have files ~5 patents with me as a coinventor