Selenium In Food And Health

352 Pages·1996·40.51 MB·English

by  Reilly, C.D.

Selenium in Food and Health
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Selenium in
Food and Health
CONOR REILLY
B.Sc., B.PHIL., H.DIP.ED., PH.D., F AIFST
Formerly Professor and Head of School,
School of Public Health,
Queensland University of Technology, Brisbane, Australia
Springer Science+Business Media, LLC
First edition 1996
© 1996 Springer Science+Business Media New York
Originally published by BIackie Academic & Professional in 1996
Softcover reprint oft he hardcover 1st edition 1996
Typeset in lOf12pt Times by Doyle Graphics Ltd, Tullamore, Ireland
ISBN 978-1-4757-6496-3 ISBN 978-1-4757-6494-9 (eBook)
DOI 10.1007/978-1-4757-6494-9
Apart from any fair dealing for the purposes of research or private study,
or criticism or review, as permitted under the UK Copyright Designs and
Patents Act, 1988, this publication may not be reproduced, stored,
or transmitted, in any form or by any means, without the prior permission
in writing of the publishers, or in the case of reprographic reproduction
only in accordance with the terms of the licences issued by the
Copyright Licensing Agency in the UK, or in accordance with the terms
of licences issued by the appropriate Reproduction Rights Organization
outside the UK. Enquiries concerning reproduction outside the terms
stated here should be sent to the publishers at the London address
printed on this page.
The publisher makes no representation, express or implied, with regard
to the accuracy of the information contained in this book and cannot
accept any legal responsibility or liability for any errors or omissions that
may be made.
A catalogue record for this book is available from the British Library
Library of Congress Catalog Card Number: 96-83008
@) Printed on permanent acid-free text paper, manufactured in accordance with
ANSI/NISO Z39.48-1992 (Permanence of Paper).
This work is dedicated to the memory of Eric John Underwood, O.A.,
C.B.E., B.Se., PH.D., D.Se., Professor of Agriculture, University of Western
Australia, 1946-69. A pioneer of international standing in studies of trace
elements in humans and animals.
Contents
Preface xiii
1 Introduction 1
1.1 The discovery of selenium 1
1.1.1 Berzelius 1
1.1.2 Predecessors of Berzelius: Arnold of Villanova and Marco Polo 2
1.2 The chemistry and physics of selenium 4
1.2.1 Allotropic forms of selenium 4
1.2.2 Physical properties 4
1.2.3 Compounds of seleniun 5
1.2.4 Organic compounds of selenium 7
1.2.5 Isotopes of selenium 7
1.3 Sources of selenium 8
1.4 Production of selenium 8
1.5 Industrial and other applications of selenium 9
1.5.1 Xerography 9
1.5.2 Other uses of selenium 10
1.6 Determination of selenium in biological and other samples 11
1.6.1 Gravimetric methods of analysis 12
1.6.2 Instrumental techniques 12
1.6.3 Neutron activation analysis 13
1.6.4 Atomic absorption spectrophotometry 14
1.6.5 Spectrofiuorimetry 16
1.6.6 Emission spectrophotometry 16
1.6.7 Mass spectrometry of trace elements 17
1.6.8 Hybrid systems 18
1.6.9 Bioassay 18
1.6.10 Sample pretreatment 19
1.7 Quality control 20
References 21
2 Biological roles of selenium 25
2.1 Origins of selenium in food and the human diet 25
2.2 Selenium in soil and water 25
2.2.1 Soil selenium availability 26
2.2.2 Selenium in surface waters 27
2.3 Selenium in plants 28
2.3.1 Crops grown on low-selenium soils 28
2.3.2 Crops grown on adequate-selenium soils 29
2.3.3 Crops grown on high-selenium soils 29
2.3.4 Selenium in food plants 30
2.4 Selenium in animal tissues 33
2.4.1 Absorption, transport and excretion of selenium 33
2.4.2 Selenium in blood and other tissues: units of concentration 35
viii CONTENTS
2.4.3 Selenium distribution in body organs 37
2.4.4 Selenium levels in whole blood 38
2.4.5 Total selenium in the human body 42
2.4.6 Excretion of selenium from the body 43
2.5 Selenium pools and stores in the body 45
2.6 Practical significance of selenium turnover 46
2.7 Selenium metabolism 46
2.7.1 Similarities and dissimilarities with sulphur metabolism 48
2.7.2 Postabsorptive transformation of selenium 48
2.8 The selenoproteins 49
2.8.1 Selenocysteine-containing proteins 49
2.8.2 Selenomethione-containing proteins 50
2.9 Other end-products of selenium metabolism 50
2.10 Selenium metabolism in outline 50
2.10.1 Selenium reduction 51
2.10.2 Methylation of selenide 52
2.11 Selenoprotein synthesis 53
2.11.1 Selenocysteine-the 21st amino acid 54
2.11.2 The UGA codon 55
2.11.3 tRNASec 55
2.11.4 Selenoprotein synthesis in eukaryotes 57
2.12 Selenium-binding proteins: selenomethionine incorporation 58
2.13 The individual selenoproteins 58
2.13.1 Glutathione peroxidases 60
2.14 Overview of the selenoproteins 64
2.15 Regulation of selenoproteins by selenium status 65
2.16 Selenium status 67
2.16.1 Assessment of selenium status 68
2.16.2 Other methods of assessing selenium status 75
References 76
3 Selenium in health and disease I 86
The agricultural connection
3.1 Selenium and agriculture 86
3.2 Selenosis in farm animals 86
3.2.1 Alkali disease and blind staggers 88
3.2.2 Control of selenosis 89
3.3 The other face of selenium-an essential nutrient 91
3.3.1 Selenium as a nutritional factor 92
3.4 Selenium-responsive conditions in animals 93
3.4.1 White muscle disease 94
3.4.2 Exudative diathesis 95
3.4.3 Hepatosis dietetica 95
3.4.4 Pancreatic degeneration 95
3.4.5 III thrift 96
3.4.6 Impaired reproduction 96
3.4.7 Impaired immune response 96
3.5 Subclinical selenium deficiencies 98
3.6 Control of selenium deficiency in livestock 100
3.7 Selenium application in fertilisers 100
3.8 Free access methods of selenium supplementation 102
3.9 Dietary supplements 103
3.10 Direct administration of selenium to animals 104
3.10.1 Drenches 104
3.10.2 Parenteral injection 104
3.10.3 Slow-release techniques 105
3.11 Implications of selenium supplementation in livestock 105
References 106
CONTENTS IX
4 Selenium in health and disease II 110
Endemic selenium-related illness in humans
4.1 Selenium toxicity 110
4.1.1 Selenium toxicity in seleniferous regions 110
4.1.2 Selenosis due to use of dietary supplements 112
4.1.3 Endemic selenosis in China 113
4.1.4 Dental caries 114
4.1.5 Other conditions associated with human selenosis 115
4.1.6 Acceptable and toxic levels of selenium in foods 116
4.2 Endemic diseases related to selenium deficiency in humans 117
4.2.1 Keshan disease 118
4.2.2 KD and selenium deficiency: similarities with animal diseases 122
4.2.3 Selenium status of residents of KD areas 122
4.2.4 Interventions in the management of KD 124
4.2.5 Fall in incidence of KD in recent years 125
4.2.6 The role of selenium in the etiology of KD 126
4.2.7 KD in Russia 126
4.3 Kaschin-Beck disease 127
4.3.1 Etiology of KBD 128
4.3.2 Preventive and therapeutic effects of selenium on KBD 129
References 129
5 Selenium in health and disease III 133
Non-endemic selenium-responsive conditions
5.1 Non-endemic selenium deficiency 133
5.1.1 TPN-induced selenium deficiency 133
5.1.2 Selenium deficiency-related muscular problems 134
5.1.3 TPN-related cardiomyopathies 134
5.1.4 Non-endemic nutritionally related selenium deficiency
cardiomyopathy 136
5.1.5 Low selenium intake and muscular problems in New Zealand 136
5.2 Other iatrogenic selenium deficiencies 136
5.3 Selenium deficiency and iodine deficiency disorders: possible connections 138
5.3.1 Thyroid biochemistry and selenium 140
5.3.2 Implications of the involvement of selenium in
thyroid hormone metabolism 141
5.3.3 Selenium and iodine interactions in thyroid metabolism 143
5.3.4 Selenium and brown adipose tissue 144
5.3.5 Selenium and iodine supplementation 145
5.4 Selenium and cancer 146
5.4.1 Ecological studies of the relation of selenium intake to
cancer incidence 147
5.4.2 Case control studies of selenium and cancer associations 148
5.4.3 'Nested' case control studies 149
5.4.4 Selenium as an anticarcinogen 154
5.4.5 Mechanism of the anticarcinogenic activity of selenium 157
5.4.6 Selenium, free radicals and cancer 157
5.4.7 Selenium, superoxide and carcinostasis: Spallholz's hypothesis 162
5.4.8 Lipid peroxidation 163
5.4.9 Lipid peroxidation, cardiovascular disease and selenium 165
5.4.10 Lipid hydroperoxides and platelet aggregation 166
5.4.11 Oxidation of low-density lipoproteins 167
5.4.12 Epidemiological studies: selenium and other antioxidants
and heart disease 167
5.4.13 The antioxidant index 171
5.4.14 Selenium and cardiotoxic heavy metals 172
References 172
x CONTENTS
6 Selenium in health and disease IV 180
Selenium and the immune response
6.1 Selenium and the immune response 180
6.1.1 Overview of immunobiological processes 181
6.1.2 Natural immunity 181
6.1.3 Phagocytosis 182
6.1.4 Acquired immunity 182
6.1.5 B cell activation 185
6.1.6 Antibodies 185
6.1.7 T cell activation 186
6.1.8 Other cells of the immune system 187
6.1.9 Nutrition and the development of the immune system 187
6.1.10 A final caution 194
6.2 Selenium and other diseases 194
6.2.1 Selenium and degenerative disorders of the eye 195
6.2.2 Sudden infant death syndrome 198
6.3 An ongoing investigation 199
References 199
7 Selenium in food 203
7.1 The inorganic components of food 203
7.1.1 Metals and metalloids 203
7.1.2 Metal contamination of food 208
7.1.3 Acceptable daily intakes and oral reference dose for
selenium in foods 209
7.1.4 Guidelines for selenium levels in drinking water 211
7.1.5 Selenium in foods 212
7.1.6 Selenium concentrations in foods: world databases 214
7.1.7 Data on selenium in foods from the US Total Diet Study 216
7.1.8 Evaluation of published analytical data on selenium in food 217
7.1.9 Variations in selenium concentrations in food in
different countries 220
7.1.10 Regional variations in selenium levels in foods 220
7.1.11 Selenium levels in human milk 222
7.1.12 Selenium in infant formula 227
7.1.13 Variation in selenium levels in other foods 228
7.1.14 Effects of processing on selenium levels in food 232
7.2 Non-nutritive aspects of selenium in foods 234
7.2.1 Selenium and the sensory qualities offood 234
7.2.2 Selenium and the problem of oxidation of milk fat 235
7.2.3 Selenium and postharvest quality of fruit: effects on
banana ripening 236
7.2.4 Effects of selenium on metabolic function in plants 236
7.2.5 The protective role of selenium against toxic substances in the diet 237
7.3 Bioavailability of selenium in foods 237
7.3.1 Definition of the term 'bioavailability' 238
7.3.2 Solubility and absorption of selenium 239
7.3.3 Biological utilisation of selenium 240
7.3.4 Bioavailability of inorganic and organic selenium compounds 241
7.3.5 Bioavailability of natural selenium compounds in food 242
7.3.6 Use of stable isotopes in the study of selenium bioavailability 246
7.3.7 A dose-response relationship to food selenium 247
References 248
CONTENTS Xl
8 Selenium in diets 257
8.1 Selenium dietary intake data 257
8.1.1 Measurement of dietary intakes of selenium 258
8.1.2 Survey techniques 258
8.1.3 Measurement of selenium intake in developed countries 260
8.1.4 Use of food composition tables to assess selenium intake 261
8.1.5 Use of hypothetical diets to estimate selenium intakes 263
8.1.6 International studies of selenium intakes 264
8.1.7 Recommended allowances, intakes and dietary reference
values for selenium 268
8.1.8 The US recommended daily allowance 271
8.1.9 Selenium intake recommendations in other countries 274
8.1.10 Revised recommendations for selenium intakes 274
8.1.11 The UK dietary reference values 276
8.1.12 Effects on selenium requirements of lifestyle and dietary practices 278
8.2 Interventions to change dietary intakes of selenium 279
8.2.1 The Finnish experiment: selenium supplementation through the
national food supply 280
8.2.2 The New Zealand response to soil selenium deficiency 283
8.2.3 The Chinese experience 285
8.3 Self-selected oral supplementation with selenium 287
8.3.1 Forms of selenium supplements 288
8.3.2 Criteria for selection of a selenium supplement 290
8.3.3 Selenium supplementation and toxicity 291
References 293
9 Selenium in the environment 300
9.1 Metals and metalloids in the environment 300
9.1.1 Selenium in the environment 300
9.1.2 Global movements of selenium 301
9.1.3 Natural selenium overload 304
9.1.4 Human activities and natural selenium 'hot spots'
in the environment 307
9.1.5 Effects of supplementation of animal feeds on selenium in the
environment 308
9.1.6 Environmental impact of the use of selenium in fertilisers 311
9.1.7 The fate of added selenium 313
9.1.8 Reservations about the addition of selenium to fertilisers 316
9.2 Environmental contamination with selenium caused by industrial
activities 317
9.2.1 Industrial pollution of the Guanajuato River Valley, Mexico 318
9.2.2 Eastern Europe 318
9.2.3 Selenium in coal ash 319
9.2.4 Selenium in industrial waste 319
9.3 Detoxification of selenium-contaminated soils by bacteria 320
9.4 Selenium in water systems: its mercury detoxification role 320
9.5 Selenium in the workplace environment 321
9.5.1 Permissible workplace limits for selenium in air 322
9.5.2 Selenium contamination in a copper refinery 322
9.5.3 Selenium contamination in the manufacture of photo receptors 323
9.5.4 The problem of disposal of selenium-containing equipment 323
9.5.5 Control of selenium in the workplace environment 324
References 325