protein and amino acid requirements in human nutrition prot

284 Pages·2017·13.05 MB·English

WHO Technical Report Series
935
PROTEIN AND AMINO ACID
REQUIREMENTS IN
HUMAN NUTRITION
Report of a Joint
WHO/FAO/UNU Expert Consultation
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WHO Technical Report Series
935
PROTEIN AND AMINO ACID
REQUIREMENTS IN
HUMAN NUTRITION
Report of a Joint
WHO/FAO/UNU Expert Consultation
WHO Library Cataloguing-in-Publication Data
Joint FAO/WHO/UNU Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition
(2002 : Geneva, Switzerland)
Protein and amino acid requirements in human nutrition : report of a joint
FAO/WHO/UNU expert consultation.
(WHO technical report series ; no. 935)
1. Proteins. 2. Amino acids. 3. Nutritional requirements. I. World Health Organization. II. Food and
Agriculture Organization of the United Nations. III. United Nations University. IV. Title. V. Series.
ISBN 92 4 120935 6 (NLM classification: QU 145)
ISSN 0512-3054
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Typeset in India
Printed in Singapore
Contents
1. Introduction 1
References 6
2. Conceptual framework for estimating protein and amino acid
requirements 9
2.1 Basic concepts 9
2.1.1 Metabolic demand 10
2.1.2 Growth 11
2.2 Dietary influences on demand 12
2.2.1 Energy 12
2.2.2 Micronutrients 12
2.2.3 Lifestyle and environmental influences 13
2.3 Achieving nitrogen balance 13
2.3.1 Maintenance amino acid catabolism and obligatory
nitrogen losses 15
2.3.2 Digestibility of dietary proteins 16
2.3.3 Protein quality: matching the supply to the demand 18
2.3.4 Protein utilization and nitrogen balance 19
2.4 Response to variation in protein intake 20
2.4.1 Changes in body composition 21
2.4.2 Labile protein reserves 21
2.4.3 Protein turnover and amino acid recycling 22
2.5 Definition of requirement 24
2.6 Adaptive mechanisms 24
2.6.1 Adaptation of amino acid oxidation 25
2.6.2 Adaptation of urea metabolism: nitrogen metabolism in
the lower gut 26
2.7 Summary metabolic model 27
References 30
3. Statistical concepts and procedures involved in deriving
recommendations for protein and amino acid requirements 35
3.1 Overview 35
3.2 Phases of requirement estimation 36
3.2.1 Gathering and screening the data 36
3.2.2 Estimating the requirements of individuals 37
3.2.3 Examining influential factors 37
3.2.4 Estimating the distribution of requirements within a
population 38
3.3 Reference requirements and intakes 39
3.3.1 Reference intakes and risk of dietary inadequacy for
individuals 39
3.3.2 Reference intakes and risk of dietary inadequacy for a
population 41
3.4 The cost of protein deficiency 45
References 47
iii
4. General methods used for determining protein and amino acid
requirements 49
4.1 Nitrogen balance 49
4.1.1 Practical aspects 50
4.1.2 Data interpretation 51
4.1.3 Other factors 54
4.1.4 General conclusion on nitrogen balance 55
4.2 Carbon balance 55
4.2.1 Practical aspects 55
4.2.2 Specific protocols 57
4.2.3 The 24-hour protocol 58
4.2.4 The fed-only protocol 61
4.2.5 Short-term fasting/feeding protocol 62
4.2.6 Data interpretation 63
4.2.7 General conclusion on carbon balance method 65
4.3 Indicator amino acid method 65
4.3.1 General approach 65
4.3.2 Summary of indicator amino acid method 70
4.4 Predictions from the obligatory nitrogen loss 71
4.5 Indirect estimates through measurement of protein utilization 71
4.6 Conclusions 72
References 73
5. Protein–energy interactions 79
5.1 Energy intakes and protein requirements 79
5.1.1 Nitrogen retention and variable energy balance 79
5.1.2 Nitrogen retention and variable energy turnover 80
5.1.3 Energy intakes and the interpretation of requirement
studies 81
5.1.4 Protein–energy interactions in children 81
5.1.5 Protein-sparing effect of non-protein energy
substrates 82
5.2 The protein:energy ratio 83
5.2.1 Protein:energy ratios as a measure of dietary protein
quality 83
5.2.2 Protein:energy ratio of requirements and dietary
assessment 84
5.2.3 Derivation of reference protein:energy ratios 85
References 89
6. Protein quality evaluation 93
6.1 Prediction of protein quality: using the protein digestibility
corrected amino acid score (PDCAAS) approach 94
6.1.1 Protein digestibility 94
6.1.2 Biological value 95
6.1.3 Amino acid score 95
6.2 Current concerns about the protein digestibility corrected
amino acid score (PDCAAS) approach 96
6.3 Conclusions 99
References 101
iv
7. Protein requirements of adults, including older people, and
women during pregnancy and lactation 103
7.1 Evaluation of published nitrogen balance studies 104
7.1.1 Adjustment for dermal and miscellaneous nitrogen
losses 104
7.1.2 Statistical analysis of nitrogen balance data 105
7.2 Population distribution of protein requirement and determination
of the median 107
7.3 Estimation of the variability and population reference intakes 108
7.4 Basal metabolic demands: the obligatory nitrogen loss 109
7.5 Potentially important influential factors identified in the
meta-analysis 110
7.5.1 Dietary source of protein 111
7.5.2 Climate 112
7.5.3 Age 112
7.5.4 Sex 112
7.6 Comparison with previous reports and other information 112
7.6.1 Dietary source of protein 113
7.6.2 Protein requirement of elderly people 114
7.6.3 Protein requirement of women 116
7.7 Protein requirements during pregnancy 116
7.7.1 Factorial approach 117
7.7.2 Nitrogen balance 119
7.7.3 Recommendations for protein intake during
pregnancy 120
7.7.4 Diet interventions during pregnancy 121
7.7.5 Twin pregnancy 121
7.7.6 Adolescent pregnancy 121
7.8 Protein requirements during lactation 122
7.9 Areas of uncertainty 123
7.10 Summary of protein requirement values for adults, including
women during pregnancy and lactation 125
References 126
8. Amino acid requirements of adults 135
8.1 Requirements for indispensable amino acids 136
8.1.1 Lysine 136
8.1.2 Leucine 138
8.1.3 Isoleucine and valine 139
8.1.4 Threonine 140
8.1.5 Aromatic amino acids 141
8.1.6 Tryptophan 143
8.1.7 Sulfur amino acids 144
8.1.8 Histidine 146
8.2 Dispensable amino acids 148
8.3 Summary of amino acid requirements in adults 149
8.4 Safe intakes of indispensable amino acids 150
8.5 Indispensable amino acid requirements in elderly people 150
v
8.6 Requirement values compared with the amino acid content of
food proteins and diets 151
References 152
9. Protein and amino acid requirements of infants and children 161
9.1 Maintenance requirement for protein 163
9.1.1 Interpretation of experimental information 163
9.1.2 Variability of maintenance 167
9.2 Protein deposition 167
9.2.1 Infants and young children, age 0–2 years 167
9.2.2 Children, age 4–18 years 168
9.2.3 Variability of protein deposition 170
9.2.4 Growth rates compared with previous estimates 171
9.3 Factorial estimates of protein requirements 171
9.3.1 Comparison with protein intakes of the breastfed infant 172
9.3.2 Implications of the estimated protein requirements for
formula-fed infants 174
9.3.3 Average protein requirements and safe levels for
infants and children from 6 months to 18 years 175
9.4 Amino acid requirements from infancy to 18 years 177
9.4.1 Infants up to 6 months 177
9.4.2 Older infants and children 178
References 182
10. Catch-up growth 185
10.1 Protein requirements for rapid weight gain in the wasted child 186
10.2 Catch-up in height in stunted children 189
References 191
11. Influence of infection on protein and amino acid requirements 195
11.1 Pattern of the protein and amino acid response to infection 196
11.2 Implications of HIV/AIDS 198
11.3 Recommendations for a protein allowance in infection 199
References 203
12. Implications of the protein and amino acid requirements
for populations in developed and developing countries 207
12.1 Protein intakes of infants associated with adequate growth
rates 208
12.2 Population intakes and the new requirement values 212
12.3 Implications of the apparent inadequacy of the diets in
developing countries 218
References 221
13. Protein intake and health 223
13.1 Renal function 224
13.2 Bone health 224
13.3 Kidney stones 226
vi
13.4 Cardiovascular disease 227
13.5 Cancer 229
13.6 Is there a maximum limit of dietary protein intake? 230
13.7 Conclusions 232
References 233
14. Summary of requirements 241
14.1 Derivation of requirements 241
14.1.1 Safe intake for individuals and populations 241
14.1.2 Precision of estimates 241
14.1.3 Age ranges 242
14.1.4 Relation to body weight 242
14.1.5 Corrections for characteristics of the diet 242
14.2 Protein requirements of adults 242
14.3 Protein requirements of infants, children and adolescents 243
14.4 Protein requirements of women during pregnancy and
lactation 244
14.5 Amino acid requirements and scoring pattern of adults 245
14.6 Amino acid requirements and scoring pattern of infants,
children and adolescents 245
14.7 Corrections for protein quality of the diet 245
14.8 Protein density of foods and the protein:energy ratio of the
requirements 246
References 247
15. Research needs 249
15.1 Recommendations for future research 250
15.2 Regulatory issues 254
References 255
Acknowledgements 257
Annex. Statistical procedures 259
Derivation of reference protein:energy ratio, individual diets 259
Estimation of distribution parameters 260
Regression 260
Analysis of variance 264
References 265
vii