Trace minerals

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Trace minerals

• Iron, zinc, iodine, selenium, copper, manganese,
  fluoride, chromium, molybdenum

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Overview

• Required in tiny amounts
• Perform unique functions
• Not fully understood
• Found in wide variety of foods, especially
  unprocessed
• Dependent on soil and water conditons during
  growth and processing
• Most common result of deficiencies in children is
  failure to grow
• Some are toxic in high levels

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Interactions

• Interactions are common among the trace minerals
  and other chemicals in body
• For instance, several trace minerals are
  associated with insulin manufacture, storage,
  release and action

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Imbalances

• Excess of one may lead to deficiency of another
• Slight excess of manganese leads to iron
  deficiency
• Deficiency of one may interfere with action of
  another
• Selenium deficiency halts activation of
  iodine-containing thyroid hormones
• Deficiencies may allow a contaminant mineral to
  cause a toxic reaction
• Iron deficiency makes the body more susceptible
  to lead poisoning

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Iron

• Found mostly in hemoglobin in blood and myoglobin
  in muscle
• Involved in transporting, releasing and storing
  oxygen needed for aerobic respiration
• Deficiencies more common in infants, young
  children, teens, women of childbearing age and
  pregnant women
• Phytates can bind to iron and make it unavailable

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Iron storage and excretion

• Iron is absorbed and excesses are stored by cells
  in mucosal cells of the small intestine
• Released into blood if needed
• Excreted in shed cells if not

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• RDA
• Men 8 mg/day
• Women 18 mg/day for women through age 50,
  8mg/day over 51
• Upper level
• 45 mg/day
• Significant sources
• Heme sources from red meats, fish, poultry
• Nonheme sources from some animal products, eggs,
  legumes, dried fruit

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Heme vs nonheme iron

• Heme iron is more easily absorbed
• Nonheme iron absorption is improved by eating
  nonheme foods with vitamin C and/or foods
  containing MFP factor (a peptide found in meat,
  fish and poultry that enhances nonheme iron
  absorption)

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Iron deficiency

• Deficiency symptoms
• Anemia, weakness, fatigue, impaired work
  performance, impaired immune system, pale skin
  and nail beds and mucous membranes, palm creases,
  concave nails, inability to regulate body
  temperature, pica (craving for non food
  substances like ice, clay, paste)

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Iron excess

• Toxicity symptoms
• GI distress, iron overload, infections, fatigue,
  joint pain, skin pigmentation, organ damage

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Iron recycling and loss

• When red blood cells wear out, they are removed
  from circulation by liver and spleen and broken
  down.
• The iron is removed and recycled to make new red
  blood cells
• Some iron is lost through GI tract and through
  hemorrhage
• Iron balance in the body is under hormonal control

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Zinc

• Cofactor of over 100 enzymes (metalloenzymes)
• All cells contain zinc, but highest
  concentrations are in muscle and bone
• Stabilizes cell membranes and defends them
  against free radicals
• Assists in growth, development and immunity

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• Necessary for synthesis, storage and release of
  insulin
• Interacts with platelets during clotting
• Affects thyroid hormone function
• Influences behavior and learning
• Needed to produce retinal and for retinol binding
  transport protein
• Essential for taste perception
• Essential for wound healing
• Essential for sperm production
• Necessary for normal fetal development

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Zinc absorption and recycling

• 15-40 is absorbed
• Zinc that is not used by intestinal cells is
  stored it is also stored by the liver
• When released, some is used by pancreas where it
  is used to make digestive enzymes, which become a
  second source of zinc for the small intestine
• Some zinc is lost in feces

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Zinc RDA, deficiency and toxicity

• Deficiency symptoms growth retardation, delayed
  sexual maturation, impaired immune function, hair
  loss, eye and skin lesions, loss of appetite
• Toxicity symptoms loss of appetite, impaired
  immunity, low HDL, copper and iron
• RDA
• Men 11mg/day
• Women 8 mg/day

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Sources of zinc

• Red meat, shell fish, whole grains, some
  fortified cereals

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Iodine

• RDA
• 150 micrograms/day
• Upper level
• 1100 micrograms/day
• Chief functions
• Needed for thyroid hormone production thyroid
  hormone regulates growth, development and
  metabolism
• Significant sources
• Iodized salt, seafood, bread, dairy products,
  plants grown in iodine rich soils, animals that
  eat iodine rich plants

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• Deficiency diseases
• Simple goiter
• Cretinism
• Deficiency symptoms
• Under active thyroid, goiter,elevated TSH mental
  and physical retardation in infants (cretinism)
• Toxicity symptoms
• Under active thyroid gland, high TSH, goiter
• Similar to deficiency symptoms because gland
  shuts down

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Selenium

• Similar to sulfur and can substitute for it in
  proteins
• Is an antioxidant that works together with
  vitamin E and glutathione oxidase to prevent free
  radical damage
• Is needed to convert thyroid hormone to its
  active form

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• RDA 55 micrograms/day
• Upper level 400 micrograms/day

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• Deficiency is associated with heart disease
  (Keshan disease)
• Toxicity symptoms loss and brittleness of hair
  and nails, skin rash, fatigue, irritability,
  nervous system disorders, garlic breath odor
• Selenium may be protective against some cancers
• Is found in seafood, meat, whole grains, fruits
  and vegetables, depending on soil content of
  selenium

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Copper

• Widely distributed in many types of cells
• RDA 900 micrograms/day
• Upper level 10,000micrograms (10 mg)/day
• Chief function
• Necessary for the absorption and use of iron in
  the formation of hemoglobin part of several
  enzymes
• Significant sources
• Seafood, nuts, whole grains, seeds, legumes
• Deficiency symptoms
• Anemia, bone abnormalities
• Toxicity symptoms
• Liver damage

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Manganese

• Found in bones and active tissues, especially
  liver, kidneys, pancreas
• AI
• Men 2.3 mg/day
• Women 1.8 mg/day
• Upper level 11 mg/day
• Chief function
• Cofactor for several enzymes
• Bone formation
• Significant sources
• Nuts, whole grains, leafy vegetables, tea

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• Deficiency symptoms
• rare
• Toxicity symptoms
• Nervous system disorders

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Fluoride

• AI
• Men 3.8 mg/day
• Women 3.1 mg/day
• Upper level
• 10 mg/day
• Chief functions
• Maintenance of bones and teeth resistance to
  tooth decay

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• Significant sources
• Fluoridated drinking water (natural or
  artificial), tea, seafood
• Deficiency symptoms
• Susceptibility to tooth decay may play a role in
  osteoporosis
• Toxicity symptoms
• Fluorosis pitting and discoloration of teeth

fluorosis
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Chromium

• AI
• Men 35 micrograms/day
• Women 25 micrograms/day
• Chief function in body
• Enhances insulin action and improves glucose
  tolerance
• Significant sources
• Meats (especially liver)
• Whole grains
• Brewers yeast
• Deficiency symptoms
• Diabetes- like condition
• Toxicity symptoms
• None reported

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Molybdenum

• RDA
• Adults 45 micrograms/day
• Upper level
• 2 mg/day
• Chief function in body
• Cofactor for several enzymes
• Significant sources
• Legumes, cereals nuts
• Deficiency symptoms
• Unknown
• Toxicity symptoms
• None reported in humans reproductive effects in
  animals

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Other trace minerals

• Nickel
• Cofactor for some enzymes
• Silicon
• Involved in formation of bones and collagen
• Vanadium
• Growth and bone development reproduction
• Cobalt
• Part of vitamin B12

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Contaminant minerals

• Interfere with normal metabolism
• Include heavy metals
• Lead causes irreversible damage to central
  nervous system
• Mercury
• Cadmium

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The end