Explains the minerals in our day to day life, their absortion, food sources, RDA, deficiency and toxicity.

1. MINERALS IN NUTRITION
Dr. R Baburaj

2. MINERALS
 Minerals are the inorganic elements, other than
carbon, hydrogen, oxygen and nitrogen, which
remain behind in the ash when food is incinerated.
 They are usually divided into two groups –
macrominerals and microminerals (or trace
elements)
 The minerals are classified as either essential or
non-essential, depending on whether or not they are
required for human nutrition and have metabolic
roles in the body.

3. MINERALS
 Non-essential elements are also categorised
as either toxic or non-toxic
 Essential in the diet
◦ Major minerals
more than 100mg/day needed
◦ Trace minerals
less than 100mg/day needed

4. MINERALS

5. MINERALS: FUNCTIONS
 Minerals function mainly in three ways in the body:
1. As structural components, e.g. calcium, phosphate
and magnesium in bones and teeth
2. In organic combinations as physiologically important
compounds, e.g. phosphorus in nucelotides, zinc
in enzymes such as carbonic anhydrase, iodine in
thyroid hormone
3. In solution in body fluids to maintain pH, help
conduct nerve impulses, control muscle contraction,
e.g. sodium and potassium in blood and intracellular
fluids
 The macrominerals are mainly involved in functions 1
and 3, and the microminerals in function 2

6. MINERALS FUNCTIONS

7. MINERALS ABSORPTION
 A normal diet, composed of a mixture of both
plant and animal foodstuffs, should supply all
the minerals required by the body.
 When such a diet is not available, or in some
other situations, it may be necessary to
provide the missing elements in the form of
supplements or by fortifying the diet with
additional minerals.
 The minerals ingested in food are absorbed
after digestion from the gut into the blood
stream, which transports them to the sites
where they function or are stored.

8. MINERALS ABSORPTION
 Not all minerals are absorbed to the same
extent. Some, including sodium and
potassium, are readily absorbed as ions or
as simple compounds.
 Others, such as calcium, magnesium and
phosphorus may be combined as indigestible
or insoluble compounds in food and are less
easily taken up from the gut.
 A few others, especially some of the trace
elements such as iron, are poorly absorbed.

9. MINERALS ABSORPTION
 Uptake of certain minerals from food can be
affected by other components of the diet. Thus
phytic acid and phytates in cereals can inhibit
absorption of iron and zinc.
 The same effect can be caused by oxalate in certain
vegetables.
 Iodine absorption can be limited by sulphur-
containing compounds known as goitrogens, which
occur in certain plants, such as some brassicae and
cassava.

10. MINERALS -HEALTH IMPLICATIONS
 If an essential element is at a low level in the diet, a
nutritional deficiency may occur, with specific
symptoms.
 Thus an inadequate intake of iron can cause anaemia
when there is insufficient haemoglobin to meet the
needs of the body for oxygen transport.
 A deficiency of iodine can lead to goitre when the
body tries to compensate for a low production of
the iodine-containing thyroid hormone by increasing
the size of the thyroid gland.

11. MINERALS -HEALTH IMPLICATIONS
 Inadequate zinc may result in growth failure in
children.
 Usually these conditions are corrected when
intake of the missing element is increased by
improving the diet or by providing
Supplements
 An excessive intake of a mineral may also have
serious consequences for health
 Too much sodium in the diet may be
associated with high blood pressure and
increased risk of a stroke.

12. MINERALS - HEALTH IMPLICATIONS
 A condition known as siderosis, in which an
excess of iron is deposited in the body, can
result when too much iron is absorbed.
 Selenosis, a sometimes fatal effect of an
excessive intake of selenium is known to
occur in parts of China where high levels of
the element enter locally grown foods from
selenium-rich soil.
 Less serious effects, such as nausea, can be
caused by a high intake of zinc.

14. MINERALS –DIETARY SOURCES
 Some food sources are better than others as
sources of minerals
 Plant foods are generally poor in iron and zinc, with
the exception of certain dark green vegetables such
as spinach
 Dairy products are generally an excellent source of
calcium
 Red meat and offal, such as liver, are the best dietary
sources of easily absorbed iron
 Many of the trace elements are found in relatively
high concentrations in fish and other sea foods

15. Sources of minerals in the food guide
pyramid

17. MINERALS –SUPPLEMENTS
 For many people supplements are an important source of
minerals
 Mineral supplements are available in a number of chemical
forms, either as inorganic compounds, such as ferrous
sulphate and calcium carbonate, or as organic
preparations such as selenium yeast and zinc
gluconate
 The products vary in the amounts of the different elements
they contain, in their absorbability and in other qualities
and while undoubtedly their use can make a definite
contribution in some cases to nutritional health, there can
also be problems such as over-dosing and interactions with
other components of the diet

18. MINERALS –SUPPLEMENTS
 The addition of minerals and other nutrients to
foods to increase their nutritional value is widely
practiced.
 In the 1920s iodised salt was introduced to help
combat endemic goitre.
 Iodised salt, as well as other iodised foods such as
bread and monosodium glutamate, are today widely
used in parts of the world where iodine deficiency
diseases (IDD) are still endemic, such as India, and
China, Papua New Guinea, Central Africa and the
Andean region of South America.

19. CALCIUM
 Without an adequate supply of the macromineral calcium in
the diet calcification of the skeleton will be adversely affected
 During early growth and development the supply of calcium
for this purpose is particularly critical and for this reason the
amount required by a child is proportionally greater than for
an adult (British Nutrition Foundation, 1989)
Calcium - RDI
 Adults 1000 mg/day
 Pregnant women 1000 mg/day
 Lactating women 1000 mg/day
 Post-menopausal women 1300 mg/day

20. CALCIUM ABSORPTION
 Uptake of calcium from food in the gut is
not very efficient.
 Only about 30% is absorbed, with 70%
lost in faeces.
 Absorption is a complex process, which
is under the control of the
cholecalciferol (vitamin D)-parathyroid
hormone system.

21. CALCIUM ABSORPTION
 Calcium is transported across the intestinal
mucosa bound to a special carrier protein.
Synthesis of this protein is stimulated by an
activated form of cholecalciferol, 1,25-
dihydroxycholecalciferol (1,25-DHCC).
 If vitamin D levels are low, calcium
absorption will be restricted and a deficiency
will occur.
 To be absorbed, calcium must be in the
soluble ionic form.

22. CALCIUM ABSORPTION
 Several food components can prevent this
happening.
 These include phytic acid (inositol
hexaphosphate) in cereals, and oxalate in
certain dark green vegetables, such as spinach,
and in rhubarb.
 Uronic acid in dietary fibre can have a
similar effect, as can free fatty acids and
certain other dietary factors, including sodium
chloride and a high protein intake.

23. Calcium
 Factors that
enhance absorption
 Stomach acid
 Vitamin D
 Lactose
 Growth hormones
 Factors that inhibit
absorption
 Lack of stomach acid
 Vitamin D deficiency
 High phosphorus intake
 High-fiber diet
 Phytates in seeds, nuts, and
grains
 Oxalates in beet greens,
rhubarb, and spinach

24. Cauliflower, watercress,
brussels sprouts, rutabaga,
kale, mustard greens, bok
choy, broccoli, turnip greens
≥ 50%
absorbed
≈ 30%
absorbed
Milk, calcium-fortified soy
milk, calcium-set tofu, cheese,
yogurt, calcium- fortified
foods and beverages
≈ 20%
absorbed
Almonds, sesame seeds,
pinto beans, sweet potatoes
≤ 5%
absorbed
Spinach, rhubarb, Swiss
chard
Bioavailability of Calcium from
selected sources

25. Weaver CM and Plawecki KL, 1994 Dietary calcium: adequacy of a
vegetarian diet. AJCN 59(suppl):1238-1241S
1 cup =240ml
Cow’s milk
168 g
Calcium equivalents
7 ¾ Cups
2 ½ Cups
7 Cups
2 slices
1 tub

26. Functions of calcium in the body
 Over 99% of body calcium is in the skeleton,
where it both provides structural support and
serves as a reservoir for maintaining plasma
levels.
 Calcium in plasma plays a number of roles, for
example in muscle contraction, neuromuscular
function and blood coagulation.
 To maintain these roles, calcium levels in the
plasma must be very stable.

27. © 2008 Thomson - Wadsworth

28. OSTEOPOROSIS
 Osteoporosis is a condition which is characterised
by loss of bone tissue from the skeleton and
deterioration of bone structure with enhanced bone
fragility and increased risk of fracture.
 It is relatively common in the elderly, especially
females, but may also occur in the young
 The higher rate in women seems to be associated
with a number of factors:
 the lower skeletal mass in women compared to
men,
 a greater rate of calcium loss and
 A fall in oestrogen production with age.

29. IRON
 Iron is the second most abundant metal in the earth’s crust,
iron insufficiency is probably the most common nutritional
deficiency in the world.
 Even among the inhabitants of well-fed developed countries it
continues to be common, especially in women
 Iron is an essential nutrient for all living organisms, with
the exception of certain bacteria.
 It has two major roles in human physiology.
 As a component of haemo- Minerals globin, the red pigment
of blood and myoglobin in muscle, iron atoms combine
reversibly with oxygen to act as its carrier from the lungs to
the tissues.

30. IRON ABSORPTION
 The uptake of iron is a complex and highly
regulated operation.
 Once the element is absorbed from the intestine
into the blood, only small amounts are lost from the
body, except when bleeding occurs.
 There is no physiological mechanism for secretion
of iron, so iron homeostasis depends on its
absorption.
 Thus the healthy individual with a good store of
iron is able to maintain a balance between the small
normal losses and the amounts of the element
absorbed from food.

31. IRON ABSORPTION
 The metal first enters the intestinal mucosal cells
where it is bound into ferritin, an iron-storage
protein. This is a large molecule from which the iron
can be readily mobilised when required.
 Some of the incoming iron may be transferred
directly by a transport protein, transferrin, to bone
marrow and other tissues to be used in the synthesis
of haemoglobin and myoglobin.

32. IRON ABSORPTION
 Iron absorption is apparently regulated by
the existing iron status of the body.
 If this is low, the absorption mechanism can
be stimulated to increased activity.
 When iron stores are high, absorption is
slowed down.
 There is evidence that other mineral
elements, such as zinc, can compete with
iron for the active absorption pathway.

33. IRON ABSORPTION
 Several other dietary factors can affect
absorption, including phytate and fibre,
which inhibit absorption, and ascorbic
acid and protein, which increase uptake.
 The pH of the gut also has an effect, with
food iron mainly in the more readily
absorbed ferrous state under acid
conditions.

34. best = heme iron
(animal sources of iron)
~25% absorbed
poor = non-haem iron
(vegetative sources)
~17% absorbed

35. If the body
does not
need iron
Iron is not absorbed and is
excreted in shed intestinal cells
instead. Thus, iron absorption
is reduced when the body does
not need iron.
If the body
needs iron
Mucosal cells in the
intestine store excess
iron in mucosal ferritin
(a storage protein).
Iron in food
Mucosal ferritin releases iron to
mucosal transferrin (a transport
protein), which hands off iron to
another transferrin that travels
through the blood to the rest of
the body.

36. Iron absorption from foods

37. Iron
Absorption-enhancing Factors
 MFP factor (MFP factor is a peptide found
in meat, fish and poultry) enhances the
absorption of nonheme iron.
 When nonheme iron is consumed with
vitamin C at the same meal,
absorption of iron increases.
 Citric acid and lactic acid from foods,
HCl from the stomach, and sugars
enhance nonheme iron absorption

38. Iron
 Absorption-inhibiting Factors
Phytates and fibers from legumes,
grains, and rice
Vegetable proteins in soybeans,
legumes, and nuts
Calcium in milk
Tannic acid and other polyphenols in
tea, coffee, grains, oregano, and red
wine

39. IRON FUNCTION
oxygen transport
cellular electron transfer (energy production)
In a variety of enzymes, such as the
cytochromes, iron atoms, present in the
ferrous and ferric states, interchange with
gain or loss of an electron, as part of the
electron chain responsible for the redox
reactions necessary for release of energy in
cellular catabolism and the synthesis of large
molecules.

40. IRON FUNCTION
Immune system
In addition to its major functions in oxygen
transport and as a cofactor in many enzymes,
iron also plays an important role in the
immune system. Although the mechanisms
involved are complex, there is good evidence
that an abnormal iron nutritional status
can lead to impaired immune function,
with serious consequences for health
Brain development

41. IRON DEFICIENCY
Iron deficiency anaemia
 Iron deficiency ultimately results in failure of
the body to produce new blood cells to
replace those that are constantly being
destroyed at the end of their normal 120-day
life span.
 Gradually the number of blood cells falls and,
with this, the amount of haemoglobin in the
blood. The cells become paler in colour and
smaller in size.

42. IRON DEFICIENCY
Iron deficiency anaemia
 These undersized cells are unable to carry sufficient
oxygen to meet the needs of tissues, so energy
release is hindered. This is what is known technically
as microcytic hypochromic anaemia, or, simply,
as iron deficiency anaemia (IDA).
 Because the fall in red blood cells occurs gradually,
IDA can exist for a considerable time before it is
clearly detected.
 By then iron stores have suffered a critical fall and
the person affected shows symptoms of chronic
tiredness, persistent headache, and, in many
cases, a rapid heart rate on exertion.

43. IRON DEFICIENCY
Iron deficiency anaemia
 There may also be other functional consequences of
iron deficiency, including a decreased work capacity, a
fall in intellectual performance, and a reduction in
immune function .
 There is today growing concern at the possibility
that iron deficiency in infancy and childhood can have
serious consequences, such as morbidity in the
newborn, defects in growth and development of
infants and impaired educational performance in
schoolchildren.

44. Iron - RDI
Adults
males  8 mg/day
females  18 mg/day
◦ pregnant women  27 mg/day
◦ lactating women  9 mg/day
Vegetarians need 1.8
times as much iron
because of low
bioavailability

45. Zinc
 Zinc deficiency in humans only began to be
recognised in the 1960s, when zinc-responsive
dwarfism was detected in children in Egypt
 Today zinc is known to be a key nutrient of
world-wide significance, and has joined iodine
and iron among trace elements whose
deficiency problems urgently need to be
addressed

46. Zinc function
 Zinc is an essential component of more
than 200 enzymes in the living world, of
which as many as 50 play important metabolic
roles in animals. It occurs in all six classes of
enzymes.
 In addition, the metal provides structural
integrity in many proteins. Zinc ligands
help maintain the structure of cell membranes
and of some ion channels.

47. Zinc function
 Zinc finger protein’ is involved in processes of
transcription factors that link with the double
helix of DNA to initiate gene expression
The expression of certain genes is known to
be regulated by the quantity of zinc absorbed
from the diet.
 It is also believed that zinc has an intracellular
role that includes regulation of cell growth
and differentiation.

48. Zinc Deficiency
 Clinical signs seen in persons suffering from marginal
zinc deficiency include depressed immunity, impaired
taste and smell, night blindness, impaired memory,
and decreased spermatogenesis in men
 Severe zinc deficiency is characterised by severely
depressed immune function, frequent infections,
bulbous pustular dermatitis, diarrhoea, alopecia and
mental disturbances
 An inadequate intake of zinc retards growth & can
result in stunting, dwarfism, failure to mature
sexually.

49. Zinc absorption from food
 An adult human contains between 1.5 and 2.5 grams
of zinc, almost as much as iron and more than 200
times the amount of copper which is the third most
abundant trace element in the body
 Absorption from the diet, which occurs in the small
intestine, is affected by a number of factors. Uptake
has been reported to range from less than 10 to
more than 90%, with an average of 20–30.
 Various components of the diet can affect uptake.
Competition for absorption occurs between zinc and
other elements, especially copper, iron and cadmium.

50. Zinc absorption from food
 Phytate, fibre, and calcium can limit
gastrointestinal uptake, whereas animal protein
enhances it.
 A diet rich in wholemeal bread, for instance,
which contains these three antagonists, has
been shown to cause deficiency of the
element.
 Zinc absorption is believed to be related to
the presence of endogenous zinc binding
ligands. Most of the zinc that is absorbed from
the intestine is found intracellularly, primarily
in muscle, bone, liver and other organs.

51. Zinc absorption from food
 Zinc in plasma is mainly loosely bound to
albumin and is also transported attached to
transferrin. In the liver it is bound to the low
molecular weight metal-binding protein,
metallothionin.
 Most of the body’s zinc reserves turn over
slowly and are not readily available for
metabolism.
 About 10% makes up a readily available pool,
which is used to maintain various zinc-
dependent metabolic functions.

52. Zinc levels in foods and dietary intakes
 In Western societies upwards of 70% of
zinc consumed is provided by animal
products, especially meat.
 Liver and other organ meats are
particularly rich in the element, as are
most seafoods. Another good source is
oysters which may, in some cases, contain
as much as 1000 mg/kg of the metal.

53. Zinc levels in foods and dietary intakes
 Other foods which contain high levels are seeds and
nuts, as well as wholegrain cereals. However, these
and other plant foods also contain phytate that can
decrease bioavailability of the element.
 In many Asian countries zinc intakes are particularly
low because of the absence of appreciable amounts
of animal products and the presence of phytate-rich
plant foods in the customary diet.

54. Zinc levels in foods and dietary intakes
 The 1989 US recommendation was
◦ 15 mg/day for adult males
◦ 12 mg/day for women up to the age of
50 years
◦ an extra 16–19 mg/day for lactating
women
◦ an additional 15 mg/day all through
pregnancy

55. Iodine
 The non-metallic element iodine is an essential
nutrient that, apparently, has a single function in the
body as a component of the thyroid hormones
thyroxine (T4) and triiodotyronine (T3)
 These hormones are necessary for a range of body
processes, the most important of which are the
control of metabolic rate, cellular metabolism,
growth and neural development
 Production of T4 and T3 is controlled by tissue
demands which are mediated by the secretions of
the pituitary gland and by the supply of iodine in the
diet

56. Iodine Deficiency
 Deficiency of iodine can result in a number of
diseases, ranging from severe cretinism with
mental retardation to barely visible
enlargement of the thyroid gland .
 Goitre is the name given to enlargement of
the gland that occurs as the body attempts to
compensate for a reduction of its supply of
iodine by increasing the size of the gland.

57. Iodine Deficiency
 The amount of enlargement is related to
the degree of iodine deficiency .
 It occurs especially in poorer remote
areas where the soil is depleted of iodine
and the general diet is limited and lacks
useful sources of the mineral.
 Goitre was once endemic, before the
introduction of iodised salt and an
improvement in the general diet.

58. Iodine levels in foods and dietary intakes
 Seafood is the major natural source of iodine
in the diet. Fish, crustaceans and
seaweeds are rich in the element.
 Milk is another good, though adventitious,
source of dietary iodine as a result of the use
of iodine-containing chemicals to sterilise
dairy equipment. This practice has now ceased
in many countries, with the result that dairy
products are decreasing in value as a source of
the nutrient.

59. Iodine levels in foods and dietary intakes
 Cereals, vegetables and meat are
generally poor sources.
 Iodised salt (sodium chloride) was
introduced in many countries in the mid-
twentieth century to combat endemic goitre
and its use led to a significant improvement in
the iodine nutritional status.
 Today, a reduction in the availability of iodised
salt, coupled with an overall decrease in
consumption of table and cooking salt, has
resulted in a fall in iodine intakes.

60. Iodine levels in foods and dietary intakes
 The RDI for iodine 150 µg.
 Higher intakes of more than 1 mg/day
may cause toxicity.
 This can be the result of excessive use of
iodine supplements or of natural iodine
rich foods (such as certain seaweeds
that can contain more than 4 mg/kg of
iodine).
 Paradoxically, high intakes of iodine
depress thyroid function and produce
goitre in certain individuals.

61. Selenium
 The metalloid selenium, although one of the rarest of the
elements, is an essential trace nutrient for humans and all
animals, but not for plants.
 Its essentiality was only recognised in the 1970s when the
enzyme glutathione peroxidase was shown to be a
selenoprotein .
 Previously the element had been known only for its toxicity.
 Selenium, in the form of the unique amino acid
selenocysteine, is the co-factor in several important
functional metalloproteins.
 At physiological pH, the selenium in the selenocysteine is
almost totally ionised and is an extremely efficient redox
catalyst.

62. Selenium
 At least 30 selenoproteins have been shown to
occur in mammalian cells. Several of these have
been fully characterised and their functions
determined.
 One group, the glutathione peroxidases, plays
role in intracellular antioxidant systems.
 Selenium is also an essential cofactor in the
iodothyronine deiodinases, which are
enzymes involved in thyroid hormone
metabolism
 Another important selenoenzyme is thioredoxin
reductase which helps to control cell growth
and division

63. Selenium deficiency
 Selenium deficiency is associated with several
diseases of major economic importance in farm
animals.
 In humans chronic low intake of dietary selenium is
responsible for Keshan disease, a sometimes fatal
cardiomyopathy which occurs especially in children
and young women, as well as for Kashin-Beck
disease, a chronic osteoarthropathy, which also
affects mainly children
 These diseases are found in parts of China and
other areas of Central Asia where soil levels of
selenium are very low.

64. Selenium deficiency
 Selenium deficiency is associated with several diseases of
major economic importance in farm animals.
 In humans chronic low intake of dietary selenium is
responsible for Keshan disease, a sometimes fatal
cardiomyopathy which occurs especially in children and
young women, as well as for Kashin-Beck disease, a chronic
osteoarthropathy, which also affects mainly children
 These diseases are found in parts of China and other areas
of Central Asia where soil levels of selenium are very low.

65. Selenium deficiency
 Several other selenium-responsive conditions
occur in humans, including cardiomyopathies and
muscular problems in patients on total parenteral
nutrition (TPN) if there is inadequate selenium in
the fluid
 Normal function of the thyroid gland is also
dependent on an adequate supply of the element.
 There is evidence that selenium deficiency can
cause a wide range of other problems including
immunodeficiency, increased susceptibility to
various forms of cancer and to coronary arterial
disease.

66. Selenium
Functions:
 Component of glutathione peroxidase
◦ catalyzes removal of hydrogen peroxide
 Component of iodothyronine-5’- deiodinase
◦ ConvertsT4 toT3
 Improves killing ability of neutrophils
◦ Reduces the prevalence and severity of
mastitis
GSH = reduced glutathione
GSSG = oxidized glutathione
GSH + H2O2 GSSG + H2O

67. Selenium dietary recommendations
 Selenium has been added relatively recently to the dietary
recommendations in some countries as evidence
establishing its important role in human health has become
officially accepted
 The UK RNI of 60mg/day for adult females and 75mg/day
for adult males, is higher than the current US Dietary
Reference Intake of 55mg/day for adults (Institute of
Medicine, Food and Nutrition Board, 2000).
 It is believed, however, by some health experts that these
intakes are insufficient to meet human needs since they do
not take into consideration the element’s critically
important protective role against oxidative damage.

68. Selenium dietary sources
 Selenium is widely distributed, but normally at levels
of less than 1 mg/kg, in most foods
 The richest sources are organ meat, such as
liver (0.05–1.33 mg/kg), muscle meat (0.06–
0.42 mg/kg) and fish (0.05–0.54 mg/kg)
 Though cereals contain only 0.01–0.31 mg/kg, cereal
products make a major contribution to intake
because of the relatively large amount of such foods
consumed in most diets.
 Another good source of the element is nuts,
particularly Brazil nuts which are the richest food
source of the element known
 Vegetables, fruit and dairy products are poor
sources

69. Selenium toxicity
 Selenium toxicity, or selenosis, has been
well documented in farm animals. It has
also occurred in humans in some parts
of China where very high levels occur in
the soil
 There have also been reports of
selenosis in individuals who consume
excessive amounts of selenium
supplements. There is some debate
about the levels of intake that will cause
toxicity

70. Selenium toxicity
 Residents of some high soil areas appear to
have no symptoms of selenium toxicity,
although they consume as much as 700mg/day.
 According to the Environmental Protection
Agency in the US, a daily intake of 5mg/kg
body weight (350mg for a 70 kg adult) is not
toxic.
 In the UK the recommended maximum safe
selenium daily intake from all sources for
adults in 6mg/kg body weight or 450mg for an
adult male individuals

71. Selenium Deficiency & Toxicity
 Deficiency
 Keshan disease- a cardiomyopathy that
affects children and women of child-bearing
age
 Toxicity
◦ Garlic-like odor of breath
◦ Nausea
◦ Vomiting
◦ Diarrhea
◦ Brittleness of teeth & fingernails

72. Magnesium
 Magnesium was first shown to be an
essential dietary component for rats in
1932 and later for humans.
 This essentiality is a reflection of the
role that magnesium plays in the
stabilization of ATP and other molecules.
 Is involved in at least 300 enzymic steps
in intermediary metabolism, for example
in the glycolytic cycle converting glucose
to pyruvate.

73. Magnesium
 Magnesium plays an important role in
the development and maintenance of
bone; about 60% of total body
magnesium is present in bone.
 Magnesium enhances the condensation
of chromatin, and given the role of
chromosomal condensation in the
regulation of gene activity, magnesium
depletion could indirectly affect gene
transcription.

74. Magnesium Deficiency &Toxicity
Magnesium deficiency causes:
 hypocalcemia and hypocalciuria
 hypokalemia resulting from excess potassium
excretion and leading to negative potassium
balance
 abnormal neuromuscular function.
 Adverse effects of excess magnesium intake
(e.g., diarrhea, nausea, abdominal cramping)
have been observed with intakes from
nonfood sources such as various magnesium
salts used for pharmacological purposes.

75. Magnesium-RDA & Dietary Sources
RDA for adult women is 320 mg/day
and for adult men is 420 mg/day.
Foods with a high magnesium
content include whole grains,
legumes, green leafy vegetables, and
tofu; meat, fruits, and dairy products
have an intermediate magnesium
content.
The poorest sources of magnesium
are refined foods.

76. Magnesium Content Of Some Foods

77. PHOSPHORUS
 Phosphorus (as phosphate) is an essential
constituent of all known protoplasm and is
uniform across most plant and animal tissues.
 Structurally, phosphorus occurs as
hydroxyapatite in calcified tissues and as
phospholipids, which are a major component
of most biological membranes, and as
nucleotides and nucleic acid.

78. PHOSPHORUS
 Other functional roles of phosphorus
include:
● buffering of acid or alkali excesses,
hence helping to maintain normal pH
● the temporary storage and transfer of
the energy derived from metabolic fuels
● by phosphorylation, and hence
activation of many catalytic proteins.

79. PHOSPHORUS
 The effects of hypophosphatemia include anorexia,
anemia, muscle weakness, bone pain, rickets and
osteomalacia, increased susceptibility to infection,
ataxia, confusion, and even death.
 Phosphorus is so ubiquitous in various foods that
near total starvation is required to produce dietary
phosphorus deficiency.
 Toxicity results in ectopic (metastatic) calcification,
particularly of the kidney & decrease calcium
absorption by complexing calcium in the chyme.

80. PHOSPHORUS
 Current RDAs for phosphorus are:
infants 100 mg (first 6 months)
275 mg (7–12 months)
children 460 mg (1–3 years)
500 mg (4–8 years)
1250 mg (9–18 years)
adults 700 mg
pregnant women 1250 mg (<18 years)
700 mg (19–50 years) and
lactating women 1250 mg (<18 years)
700 mg (19–50 years)

81. Key:
Fruits
Milk and milk products
Legumes, nuts, seeds
Meats
Best sources per kcalorie
Breads and cereals
Vegetables
PHOSPHORUS
Protein-rich sources, such as
milk (white), meats (red), and
legumes (brown), provide
abundant phosphorus as well.
RDA
for
adults
Food Serving size (kcalories)
Milligrams
Phosphorus in Selected Foods

82. Sodium
 fluid volume regulator, electrolyte balancer
 Source- mostly in processed foods
 Deficiency- must be replaced with water if
blood sodium drops
 Toxicity- edema and hypertension
 diet moderate in sodium is recommended

83. Chloride
 essential nutrient
 fluid and electrolyte balance
 abundant in foods (especially processed)
◦ part of sodium chloride
 rarely lacking
 dehydration due to water deficiency
 Dietary Requirement:Average requirements
for sodium and chloride are estimated to be
about 500 and 750 mg/day, respectively.

84. Potassium
 maintaining fluid and electrolyte balance
◦ affects homeostasis, such as a steady heartbeat
 found in both plant and animal cells
◦ found less in processed foods
◦ Legumes, potatoes, seafood, dairy products, meat,
fruits
 deficiency
◦ hypertension
◦ most common electrolyte imbalance
◦ muscle weakness
 toxicity
◦ rare from food
◦ over consumption of supplements
 Adult requirements for potassium are estimated

85. What Processing Does to
Sodium and Potassium Contents of Foods
Milk (whole)
Unprocessed
Peach pie
Processed
Canned,
cream corn
Instant
pudding
Oat cereal
Fresh peaches
Milks
Chipped beef
Vegetables
Fresh corn
Meats
Roast beef
Fruits
Rolled oats
Grains
Sodium
Potassium
Key:

86. Copper
Functions:
 Component of several enzymes, cofactors, and
proteins in the body.
 In the proper functioning of the immune, nervous
and cardiovascular systems, for bone health,
 For iron metabolism and formation of red blood
cells, and in the regulation of mitochondrial and
other gene expression.
 Functions as an electron transfer intermediate in
redox reactions and as a cofactor in several copper
containing metalloenzymes.

87. Copper-Deficiency & Toxicity
Deficiency
◦Hospitalized patients & preterm
infants
Signs & Symptoms
◦Defective connective tissue,
anemia, neural problems
Toxicity
◦Rare

88. Copper – Requirements & Dietary Sources
 Estimates of average intakes of
copper are about 1.5 and 1.2 mg
copper/day for men and women,
respectively.
 Rich food sources of copper
include seafood, nuts, seeds, legumes,
wholegrain cereals, and chocolate.

89. Manganese
Functions:
 Required as a catalytic cofactor for
mitochondrial superoxide dismutase,
arginase, and pyruvate carboxylase.
Cofactor for many enzymes that
metabolize carbohydrates, lipids and
amino acids

90. Manganese Deficiency & Toxicity
 Deficiency
◦ Rare
◦ Scaly skin, poor bone formation, growth
faltering
 Toxicity
◦ Rare
 Mine workers
 Liver disease

91. Manganese-Requirements & Dietary Sources
 High concentrations present in cereals, brown bread,
nuts, ginger, and tea.
 AI :
➢ infants 0.003 mg (first 6 mnts), 0.6 mg (7–12 mnts),
➢ children 1.2 & 1.5 mg (1–3 and 4–8 years, resply),
➢ teenage boys 1.9 & 2.2 mg (9–13 &14–18 yrs, resply),
➢ adult men 2.3 mg (19 years and older),
➢ teenage girls 1.6 mg (9–18 years),
➢ adult women 1.8 mg (19 years and older),
➢ pregnant women 2.0 mg,
➢ lactating women 2.6 mg.

92. Molybdenum
Function:
 Cofactor for the iron- and flavin-
containing enzymes that catalyze the
hydroxylation of various substrates.
 Deficiency
◦ Rare
 Toxicity
◦ No known effects in humans
◦ Animals – disrupts reproduction

93. Molybdenum : Dietary Sources &
Requirements
 Adult requirements for molybdenum
have been estimated at about 45
μg/day.
 Milk, beans, bread, and cereals
(especially the germ) are good sources
of molybdenum, and water also
contributes small amounts to the total
dietary intakes.

94. Chromium
Function:
 Essential nutrient involved in carbohydrate and lipid
metabolism
◦ maintains glucose homeostasis
 Deficiency
 Elevated blood glucose
 Decreased insulin sensitivity
 Weight loss
 Toxicity
◦ Rare
◦ Industrially released chromium
• Richest dietary sources of chromium are spices such as
black pepper, brewer’s yeast, mushrooms, prunes, raisins,
nuts, asparagus, beer, and wine.

95. Chromium
 AI values:
- infants 0.2 μg (first 6 months), 5.5 μg (7–12 months),
- children 11 and 15 μg (1–3 and 4–8 years, respectively),
- teenage boys 25 and 35 μg (9–13 and 14–18 years,
respectively),
- adult men 35 and 30 μg (19–50 years and 50 years & older,
resp),
- teenage girls 21 and 24 μg (9–13 and 14–18 years,
respectively),
- adult women 25 and 20 μg (19–50 years and 51 years and
older, respectively),
- pregnant women 29 and 30 μg (less than 18 years and 19–
50 years, respectively), and
- lactating women 44 and 45 μg (less than18 and 19–50 years,
respectively).

96. Fluoride
 99% is found in bones and
teeth
 Function
◦ to promote
mineralization of calcium
and phosphate.
◦ Inhibits bacterial growth
in mouth→decreases
cavity formation.

97. Fluoride- Deficiency & Toxicity
 Deficiency
◦ Results in increased risk of dental caries
 Toxicity
◦ GI upset, excessive production of saliva, watery
eyes, heart problems, coma
◦ Dental fluorosis
◦ Skeletal fluorosis

98. Fluoride- Requirements & Dietary Sources
 Dietary sources:Tea, marine fish , toothpaste,
added to drinking water.
 AI values for fluoride:
- infants 0.01 mg (first 6 months), 0.5 mg (7–12
months),
- children and adolescents 0.7, 1.0, and 2.0 mg (1–3,
4–8, and 9–13 years,respectively),
- male adolescents and adults 3 and 4 mg(14–18 and
19 years and older, respectively),
- female adolescents and adults 3 mg (over 14 years,
including pregnancy and lactation).

99. Ultra Trace Minerals
 Nickel
 Aluminum
 Silicon
 Vanadium
 Arsenic
 Boron