Biofortification optimizing iron absorption from beans and other staple foods

228 Pages·2011·6.17 MB·English

ETH Library
Biofortification
optimizing iron absorption from beans and other
staple foods
Doctoral Thesis
Author(s):
Petry, Nicolai
Publication date:
2011
Permanent link:
https://doi.org/10.3929/ethz-a-006682299
Rights / license:
In Copyright - Non-Commercial Use Permitted
This page was generated automatically upon download from the ETH Zurich Research Collection.
For more information, please consult the Terms of use.
Diss. ETH No. 19787

BIOFORTIFICATION: OPTIMIZING IRON
ABSORPTION FROM BEANS AND OTHER STAPLE FOODS

A dissertation submitted to
ETH Zürich

for the degree of
Doctor of Science

presented by
NICOLAI PETRY

Dipl. oeco. troph., Rheinische Friedrich-Wilhelms-Universität Bonn, Germany
born 09.08.1977
citizen of Germany

accepted on the recommendation of
Prof. Dr. Richard F. Hurrell, examiner
Dr. Ines Egli, co- examiner
Prof. Dr. Manju Reddy, co-examiner

2011

Acknowledgements
I would like to thank Prof. Dr. Richard Hurrell for all the fruitful discussions, for his great ideas
and for his guidance during the last years.
I am also very grateful to Dr. Ines Egli for supervising my thesis and for all her contributions
and support which helped me to accomplish my work.
Special thanks go to Prof. Dr. Thomas Walczyk for sharing his creative ideas and for taking
the time to answer my questions.
I would like to thank Dr. Erick Boy for his constructive feedback and for supporting me during
my time in Rwanda.
I am very grateful to Dr. Pierrot Tugirimana for his undying support in solving problems I
encountered in Rwanda making the execution of the bean studies possible.
I would like to thank Prof. Dr. Jean Bosco Gahutu for his collaboration and for letting me use
the laboratory facilities at NUR.
Prof. Dr. Manju Reddy is kindly acknowledged for accepting the task of co-examiner.
I would like to thank Dr. Christophe Chassard for sharing with me his outstanding knowledge
in human gut microbiota.
I would like to thank all the former and present members of the Human Nutrition for an
unforgettable time.
Financial support by HarvestPlus is gratefully acknowledged.
Thanks a lot, Doreen, Jasmin, Fäbi and Babs for proofreading the manuscript, you were a
great help!
Finally I would like to thank my family and friends for being there when I needed them most!

Table of contents

TABLE OF CONTENTS

Abbreviations v
Summary 1
Zusammenfassung 5
Introduction 11
1 BIOFORTIFICATION 13
1.1 Biofortification as a tool to combat micronutrient deficiencies 13
1.1.1 The impact pathway of biofortification 17
1.1.2 Discovery 18
1.1.3 Development 21
1.1.3.1 Traditional plant breeding versus genetic engineering 23
1.1.3.2 Micronutrient fertilizers 25
1.1.3.3 The targeted crops for biofortification - state of the art 25
1.1.3.3.1 Wheat 26
1.1.3.3.2 Rice 27
1.1.3.3.3 Maize 28
1.1.3.3.4 Cassava 30
1.1.3.3.5 Sweet potato 30
1.1.3.4 Phaseolus vulgaris- A vehicle for iron biofortification? 31
1.1.3.5 Genetic variation of iron in common bean seeds 32
1.1.3.6 Isotope studies- A tool to measure the impact of iron biofortification 35
1.1.3.6.1 Single vs. multiple meal studies 36
1.1.4 Dissemination 38
2 IRON ABSORPTION INHIBITORS AND ENHANCERS 41
2.1 Polyphenols 42
2.1.1 Nomenclature 42
2.1.1.1 Lignans and stilbenes 43
2.1.1.2 Hydroxybenzoic acids 44
2.1.1.3 Hydroxycinnamic acids 44
2.1.1.4 Flavonoids 45
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Table of contents

2.1.2 Biosynthesis of different PP compounds 48
2.1.3 PP intake and major sources 50
2.1.3.1 Beverages 51
2.1.3.1.1 Tea 51
2.1.3.1.2 Coffee 52
2.1.3.1.3 Beer 52
2.1.3.1.4 Wine 52
2.1.3.1.5 Cocoa and chocolate 53
2.1.3.2 Fruits 53
2.1.3.2.1 Apples, Pears and other fruits 53
2.1.3.3 Vegetables 54
2.1.3.3.1 Carrot, onions, broccoli, spinach, eggplant, zucchini, tomatoes 54
2.1.3.4 Beans 55
2.1.3.5 Sorghum 57
2.1.4 Absorption of PP 57
2.1.4.1 Absorption of intact PP structures 58
2.1.4.2 Microbial PP degradation and absorption of metabolites 60
2.1.5 Positive health impacts of polyphenols 61
2.1.5.1 Cancer 61
2.1.5.2 Cardiovascular diseases 62
2.1.5.3 Impact of PP on carbohydrate metabolism 63
2.1.5.4 Bone health 63
2.1.5.5 Estrogens 63
2.1.5.6 Impact of PP on gut health 64
2.1.6 Negative health impacts of polyphenols 64
2.1.6.1 Interaction of polyphenols with iron 64
2.1.6.1.1 The nature of iron polyphenol complexes 64
2.1.6.1.2 Iron isotope absorption studies in human subjects 66
2.1.6.1.3 Recent Caco-2 cell studies on the inhibition mechanism 69
2.1.6.1.4 Factors influencing the PP: iron complex formation 70
2.1.6.1.5 Reducing polyphenol levels in the diet 71
2.2 Phytic acid 73
2.2.1 Occurrence 73
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Table of contents

2.2.2 Inhibition of mineral absorption 73
2.3 Inulin and Oligofructose 77
2.3.1 Properties of Inulin and Oligofructose 79
2.3.2 The industrial application of inulin and oligofructose 80
2.3.3 The influence of Inulin and oligofructose on gut microbiota 82
2.3.4 Fermentation products of bacterial metabolism 85
2.3.5 Modulation of SCFA profile by inulin and oligofructose 88
2.3.6 The impact of inulin on human health 89
2.3.6.1 Cancer prevention 90
2.3.6.2 Immune system modulation 91
2.3.6.3 Lipid metabolism 92
2.3.6.4 Possible negative health impacts 93
2.3.7 The influence of inulin and oligofructose on mineral absorption 94
2.3.7.1 Calcium 94
2.3.7.2 Iron 96
2.3.7.2.1 Evidence for colonic iron absorption 96
2.3.7.2.2 Possible mechanisms of inulin on colonic iron absorption 98
2.3.7.3 Other minerals 101
3 REFERENCES 102

Manuscript 1 145
Manuscript 2 167
Manuscript 3 189
Conclusions and perspectives 211
Curriculum vitae 217

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Table of contents

iv
Abbreviations

Abbreviations

AACC American Association of Cereal Chemists
ACF Aberrant crypt foci
CBG Cytosolic beta- glucosidase
CGIAR Consultative Group on International Agricultural Research
CHI Chalcone isomerase
CHS Chalcone synthase
CIAT International Center for Tropical Agriculture
DALYs Disability-Adjusted Life Years
Dcybt Duodenal cytochrome B
DMT1 Divalent cation transporter 1
DNA Deoxyribonucleic acid
DP Degree of polymerization
DRC Democratic Republic of the Congo
EDTA Ethylenediaminetetraacetic acid
EGCG Epigallocatechin-3-gallate
FAO Food and Agriculture Organization
Fe Iron
GAE Gallic acid equivalents
GALT Gut associated lymphoid tissue
GC Gas chromatography
G x E Genetic and Environment
GLUT Sodium independent glucose transporter
GMO Genetically modified organism
GSE Grape seed extract
HYV High yield varieties
IBD Inflammatory bowel disease
IBS Irritable bowel syndrome
ID Iron deficiency
IgA Immunoglobulin A
IL Interleukin
IP6 Myo- inositol- 1, 2, 3, 4, 5, 6- hexakisphosphate
IRRI International Rice Research Institute
v