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The Nutritional Trace Metals

The Nutritional Trace Metals

Conor Reilly

ISBN: 978-1-405-14811-5

Apr 2008

356 pages



The Nutritional Trace Metals covers the roles played by trace metals in human metabolism, a relatively neglected area of human metabolism and nutrition. The book focuses its attention on the vital roles played by the relatively small number of trace metal nutrients as components of a wide range of functional proteins. Its structure and content are largely based on the approach adopted by the author, Professor Conor Reilly, during more than 30 years of teaching nutrition to a wide range of undergraduate and postgraduate students.

The introductory chapter covers the roles of metals in life processes, the metal content of living systems and metals in food and diets. This is followed by chapters, each dealing with an individual trace metal. Those discussed are iron, zinc, copper, selenium, chromium, manganese, molybdenum, nickel, boron, vanadium, cobalt, silicon and arsenic. In each case attention is given to the metal's chemistry and metabolic roles, including absorption, transport, losses, status and essentiality, as well as the consequences both of deficiency and excess.

The Nutritional Trace Metals is essential reading for nutritionists, dietitians and other health professionals, including physicians, who wish to know more about these vital components of the diet. The book will also be of value to food scientists, especially those involved in food fortification and pharmaceutical product formulation. It will be an invaluable reference volume in libraries of universities and research establishments involved in nutrition teaching and research.

Conor Reilly is Emeritus Professor of Public Health at the Queensland University of Technology, Brisbane, Australia, and is also Visiting Professor of Nutrition at Oxford Brookes University, Oxford, U.K.


1 Introduction.

1.1 The role of metals in life processes – a belated recognition.

1.1.1 Bioinorganic chemistry.

1.1.2 A brief review of the metals. What are the metals?. Chemical properties of the metals. Representative and transition metals. The biological functions of trace metals.

1.2 The metal content of living systems.

1.2.1 Metals in human tissue.

1.2.2 Essential and non-essential elements.

1.2.3 The essentiality of trace metals.

1.3 Metals in food and diets.

1.3.1 Variation in metal concentrations in foods. Chemical forms of metals in food.

1.3.2 Determination of levels of trace metals in food.

1.3.3 How do metals get into foods?. Metals in soils. Soil as a source of trace metals in plants and in human diets. Effects of agricultural practices on soil metal content. Uptake of trace metals by plants from soil. Accumulator plants.

1.3.4 Non-plant sources of trace metal nutrients in foods.

1.3.5 Adventitious sources of trace metals in foods.

1.3.6 Food fortification 3.7 Dietary supplements.

1.3.8 Bioavailability of trace metal nutrients in foods.

1.3.9 Estimating dietary intakes of trace metals. A hierarchical approach to estimating intakes. Other methods for assessing intakes.

1.3.10 Recommended allowances, intakes and dietary reference values. The US RDAs of 1941. Estimated Safe and Adequate Daily Dietary Intakes.

1.3.11 Modernising the RDAs. The Us Dietary Reference Intakes for the twenty-first century. The UK’s Dietary Reference Values. Australian and New Zealand Nutrient Reference Values. Other nutrient intake recommendations.

2 Iron.

2.1 Introduction.

2.2 Iron Chemistry.

2.3 Iron in the Body.

2.3.1 Haemoglobin.

2.3.2 Myoglobin.

2.3.3 Cytochromes. Cytochrome P-450 enzymes.

2.3.4 Iron-sulphur proteins.

2.3.5 Other Iron enzymes.

2.3.6 Iron-Transporting Proteins. Transferrin. Lactoferrin. Ferritin. Haemoseridin.

2.4 Iron absorption.

2.4.1 The luminal phase of iron absorption. Inhibitors of iron absorption. Effect of tannin in tea on iron absorption. Dietary factors that enhance iron absorption. Non-dietary factors that affect iron absorption.

2.4.2 Uptake of iron by the mucosal cell.

2.4.3 Handling of iron within the intestinal enterocyte.

2.4.4 Export of iron from the mucosal cells.

2.4.5 Regulation of iron absorption and transport.

2.5 Transport of iron in plasma.

2.5.1 Iron turnover in plasma.

2.6 Iron losses.

2.7 Iron status.

2.7.1 Methods for assessing iron status. Measuring body iron stores. Measuring functional iron.

2.7.2 Haemoglobin measurement.

2.7.3 Iron deficiency.

2.7.4 Iron deficiency anaemia (IDA). Consequences of IDA. Anaemia of chronic disease (ACD).

2.7.5 Iron overload. Haemochromatosis. Non-genetic iron overload.

2.7.6 Iron and cellular oxidation.

2.7.7 Iron, immunity and susceptibility to infection. Iron and infection.

2.7.8 Iron and cancer.

2.7.9 Iron and coronary heart disease.

2.8 Iron in the diet 2.8.1 Iron in foods and beverages.

2.8.2 Iron fortification of foods. Bioavailability of iron added to foods. Levels of iron used in food fortification. Adventitious iron in food.

2.8.3 Dietary intake of iron.

2.9 Recommended intakes of iron.

2.10 Strategies to combat iron deficiency.

2.10.1 Iron fortification of dietary staples.

2.10.2 Use of iron supplements.

2.10.3 The effect of changing dietary habits on iron status.

3 Zinc.

3.1 Introduction.

3.2 Zinc distribution in the environment.

3.3 Zinc chemistry.

3.4 The biology of zinc.

3.4.1 Zinc enzymes.

3.4.2 Zinc finger proteins.

3.5 Absorption and metabolism of zinc.

3.5.1 Chemical forms of zinc in food.

3.5.2 Promoters and inhibitors of zinc absorption.

3.5.3 Relation of zinc uptake to physiological state.

3.6 Zinc homeostasis.

3.6.1 Zinc absorption in the gastrointestinal tract. Transfer of zinc across the mucosal membrane. Zinc transporters.

3.6.2 Regulation of zinc homeostasis at different levels of dietary intake.

3.6.3 Effect of changes in zinc intake on renal losses.

3.6.4 Other sources of zinc loss.

3.7 Effects of changes in dietary zinc intakes on tissue levels.

3.7.1 Zinc in bone.

3.7.2 Zinc in plasma.

3.8 Effects of zinc deficiency.

3.8.1 Sever zinc deficiency.

3.8.2 Mild zinc deficiency.

3.8.3 Zinc deficiency and growth in children. Zinc deficiency and diarrhoea in children. Zinc deficiency and infection in children. Zinc deficiency and neurophysiological behaviour.

3.9 Zinc and the immune system.

3 .9.1 Zinc and the thymulin activity.

3.9.2 Zinc and the epidermal barriers to infection.

3.9.3 Zinc and apoptosis.

3.9.4 Effects of high zinc intake on the immune system.

3.9.5 Effect of zinc on immunity in the elderly.

3.10 The antioxidant role of zinc.

3.10.1 Zinc metallothionein.

3.10.2 Nitric oxide and zinc release from MT.

3.11 Zinc requirements.

3.11.1 WHO estimates of zinc requirements.

3.11.2 Recommended intakes for zinc in the US and the UK.

3.12 High intakes of zinc.

3.13 Assessment of zinc status.

3.13.1 An index of suspicion of zinc deficiency.

3.13.2 Assessment of zinc status using plasma and serum levels.

3.13.3 Assessment of zinc status from dietary intake data.

3.13.4 Use of zinc-dependent enzymes to assess zinc status.

3.13.5 Other biomarkers for assessing zinc status.

3.14 Dietary sources and bioavailability of zinc.

3.14.1 Dietary intake. of zinc in the UK.

3.15 Interventions to increase dietary zinc intake.

3.15.1 Zinc supplementation of the diet.

3.15.2 Zinc fortification of foods.

3.15.3 Dietary diversification and modification to increase zinc intake.

3.15.4 An integrated approach to improving zinc nutriture in populations.

4 Copper.

4.1 Introduction.

4.2 Copper chemistry.

4.3 The biology of copper.

4.3.1 Copper proteins. Cytochrome-c oxidase. The ferroxidases. Copper/zinc superoxide dismutase. Amine oxidases. Tyrosinase. Other copper proteins.

4.4 Dietary sources of copper.

4.5 Copper absorption and metabolism.

4.5.1 Effects on copper absorption of various food components. Effect of amino acids on copper absorption. Competition between copper and other metals for absorption. Effects of dietary carbohydrates and fibre on copper absorption.

4.5.2 Copper absorption from human and cow’s milk.

4.5.3 Transport of copper across the mucosal membrane.

4.6 Distribution of copper in the body.

4.7 Assessment of copper status.

4.7.1 Assessment of copper status using plasma copper and caeruloplasmin.

4.7.2 Copper enzyme activity.

4.7.3 Relation of immunity to copper status.

4.7.4 Responses to copper supplementation.

4.8 Copper requirements.

4.8.1 Copper deficiency. Copper deficiency and heart disease.

4.8.2 Recommended and safe intakes of copper. Upper limits of intake.

4.8.3 Dietary intakes of copper.

5 Selenium.

5.1 Introduction.

5.2 Selenium chemistry.

5.2.1 Selenium compounds. Organo-selenium products.

5.3 Production of selenium.

5.3.1 Uses of selenium.

5.4 Sources and distribution of selenium in different soils.

5.4.1 Selenium in soil and water.

5.4.2 Availability of selenium in different soils.

5.4.3 Selenium in surface waters.

5.5 Selenium in foods and beverages.

5.5.1 Variations in selenium levels in foods.

5.5.2 Sources of dietary selenium. Brazil nuts.

5.5.3 Dietary intakes of selenium. Changes in dietary intakes of selenium: Finland and New Zealand.

5.6 Absorption of selenium from ingested foods.

5.6.1 Retention of absorbed selenium. The nutritional significance of selenomethionine.

5.6.2 Excretion of selenium.

5.6.3 Selenium distribution in the human body.

5.6.4 Selenium levels in blood. Selenium in whole blood. Selenium in serum and plasma. Selenium levels in other blood fractions.

5.7 Biological roles of selenium.

5.7.1 Selenium-responsive conditions in farm animals.

5.7.2 Functional selenoproteins in humans. Glutathione peroxidases (GPXs). Iodithyronine deiodinase (ID). Thioredoxin reductase (TR). Other selenoproteins.

5.7.3 Selenoprotein synthesis. Selenocysteine, the 21st amino acid. Selenocysteine synthesis.

5.8 Selenium in human health and disease.

5.8.1 Selenium toxicity.

5.8.2 Effects of selenium deficiency. Keshan disease. Kashin-Beck disease (KBD).

5.8.3 Non-endemic selenium deficiency-related conditions. TPN-induced selenium deficiency. Other iatrogenic selenium deficiencies. Selenium deficiency and iodine deficiency disorders. selenium deficiency and other diseases.

5.8.4 Selenium and cancer.

5.8.5 Selenium and the immune response.

5.8.6 Selenium and brain function.

5.8.7 Selenium and other health conditions.

5.9 Recommended allowances, intakes and dietary reference values for selenium.

5.10 Perspectives for the future.

6 Chromium.

6.1 Introduction.

6.2 Chemistry of chromium.

6.3 Distribution, production and uses of chromium.

6.4 Chromium in food and beverages.

6.4.1 Adventitious chromium in foods.

6.5 Dietary intakes of chromium.

6.6 Absorption and metabolism of chromium.

6.6.1 Essentiality of chromium. Chromium and glucose tolerance.

6.6.2 Mechanism of action of chromium.

6.6.3 Chromium and athletic performance.

6.7 Assessing chromium status.

6.7.1 Blood chromium.

6.7.2 Measurements of chromium in urine and hair.

6.8 Chromium requirements.

6.9 Chromium supplementation.

7 Manganese.

7.1 Introduction.

7.2 Production and uses of manganese.

7.3 Chemical and physical properties of manganese.

7.4 Manganese in food and beverages.

7.5 Dietary intake of manganese.

7.6 Absorption and metabolism of manganese.

7.6.1 Metabolic functions of manganese.

7.6.2 Manganese deficiency.

7.6.3 Manganese toxicity.

7.7 Assessment of manganese status and estimation of dietary requirements.

7.7.1 Manganese dietary requirements.

8 Molybdenum.

8.1 Introduction.

8.2 Distribution and production of molybdenum.

8.3 Chemical and physical properties of molybdenum.

8.4 Molybdenum in food and beverages.

8.5 Dietary intakes of molybdenum.

8.6 Absorption and metabolism of molybdenum.

8.6.1 Molybdenum deficiency.

8.6.2 Molybdenum toxicity. Toxicity from molybdenum in dietary supplements.

8.7 Molybdenum requirements.

9 Nickel, boron, vanadium, cobalt and other trace metal nutrients.

9.1 Introduction.

9.2 Nickel.

9.1.1 Chemical and physical properties of nickel.

9.2.2 Nickel in food and beverages.

9.2.3 Dietary intake of nickel. Intake of nickel from dietary supplements.

9.2.4 Absorption and metabolism of nickel.

9.2.5 Dietary requirements for nickel.

9.3 Boron.

9.3.1 Chemical and physical properties of boron.

9.3.2 Uses of boron.

9.3.3 Boron in food and beverages. Dietary intake of boron. Boron intakes by vegetarians. Boron intakes from supplements.

9.3.4 Absorption and metabolism of boron.

9.3.5 Boron: an essential nutrient?.

9.3.6 An acceptable daily intake for boron.

9.4 Vanadium.

9.4.1 Chemical and physical properties of vanadium.

9.4.2 Production and uses of vanadium.

9.4.3 Vanadium in food and beverages. Dietary intakes of vanadium. Intake of vanadium from dietary supplements.

9.4.4 Absorption and metabolism of vanadium.

9.4.5 Vanadium toxicity.

9.4.6 Vanadium requirements.

9.5 Cobalt.

9.5.1 Chemical and physical properties of cobalt.

9.5.2 Production and uses of cobalt.

9.5.3 Cobalt in food and beverages.

9.5.4 Absorption and metabolism of cobalt.

9.5.5 Dietary intake recommendations for cobalt. Safe intakes of cobalt.

9.6 Other possibly essential trace metals and metalloids.

9.6.1 Silicon.

9.6.2 Arsenic.

9.6.3 Other as-yet unconfirmed essential trace metals and metalloids.


""This book discusses the role played by trace metals in human metabolism. It is intended for use by food scientists in fields such as food fortification as well as nutritionists, dietitians and other health professionals wanting to learn more about trace metals as dietary components.""
Food Science & Technology Abstracts, Vol 37 (3) 2005

""This book covers the roles played by trace elements in human metabolism. It provides information on thir nature and function, and discusses reports from the specialist literature, highlighting current thinking concerning the effect of these trace elements.
This book will be particularly useful for undergraduates in dietetics and nutrition courses and will be of value to medical and pharmaceutical and other healthprofessionals, including alternative health practitioners.
It could also serve as a reference book for food scientists and technologists, as well as for administrators and others in the food industry who need to nore more about the nutritional trace elements that occur in processed and other foods either naturally or added in fortification.""
CAB Abstracts, 2005

""The Nutritional Trace Metals is a unique reference source for food scientists and technologists (espicially those involved in food fortification and pharmaceutical product formulation. i.e. nutraceuticals and functional foods), dietiticans and other health professionals, including physicians, who wish to know more about these vital components of the diet.""

International Journal of Food Science and Technology 2005

""...essential reading for public health professionals.""

""The selenium chapter is a tour de force with a wide ranging discussion on the magnitude and implications of selenium defiency"".

""This is a fine addition to the body of available literature on trace metals of nutritional significance and covers teh important trace elements including iron, zinc, copper, selenium, manganese, molybdenum, etc"".

Maternal and Child Nutrition Volume 2 Issue 2 April 2006

* vital information for all nutritional scientists
* the area has been neglected in many previous nutrition books
* extremely well-respected and well-known author
* commercially-useful information on ingredients for food companies