3. lectures.minerals & trace elements

8/12/2019 3. Lectures.minerals & Trace Elements

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Mineral Classification

Macrominerals Microminerals

Calcium IronPhosphorus Zinc

Magnesium Copper

Sulfur Selenium

Sodium ChromiumPotassium Iodine

Chloride Fluoride


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Calcium

Structure: in foods as inorganic salts (carbonates, phosphates andsilicates), complexes with oxalated, phytates and proteins

Food Sources:

Milk and milk products, legumes, canned fish (including bones)

Functions:

Hardening of bones and teeth

Nerve functioning

Muscle contraction

RDI: 800 mg/day for men and 1000 mg/day for women


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Calcium

Deficiency:

Rickets

Osteoporosis

Therapeutic Effects:

May reduce hypertension

May play a role in weight reduction

Toxicity:None

Plasma levels tightly regulated

Kidney stones??


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Magnesium

Structure: complexes with proteins, chlorophyll etc

Food Sources:

Whole grains (wheat bran), broccoli, squash, beans, nuts, seeds

Hard tap water

Functions:

Key component of enzymes

Cell membranes & bone crystal

RDI: 270 mg for females, 300 mg for males, additional 30 mg during

pregnancy and 70 mg/day during lactation


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Magnesium

Deficiency:

Rare

Use of thiazide diuretics may increase urinary excretion


None well established

Back or shoulder or other muscular pain

Toxicity:

None in healthy humans who eats natural foods

May reduce calcium absorption


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Iron

2+

Ferric (Fe3+)

&

Ferrous (Fe2+)


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Iron

Structure:

Heme or non-heme iron

Food Sources:

Meat, fish (clams and oysters) & poultry

Dark green leafy vegetables, breakfast cereals, egg yolk, black strap

molasses, nuts, seeds & dried fruits

Milk is a poor source of iron

Functions:

Oxygen transport

Synthesis of collagen

Synthesis of neurotransmitters (dopamine, epinephrine, norepinephrineand serotonin)

RDI: 9 mg/day for 7-12 month infants; 6-8 mg for up to 7 years

10-13 mg/day for males, 12-16 mg/day for females; 22-36 mg/dayduring pregnancy; 7 mg/day for postmenopausal women


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Iron

Deficiency:

Iron Deficiency Anaemia


None

Toxicity:

Hemochromatosis


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Zinc

Structure: in foods as inorganic salts and complexes with proteins

Food Sources:

Oysters, wheat germ, beef, calf liver, dark meat of turkey and chicken andwhole grains, particularly wheat

Functions:

Key component of enzymes

Protein synthesis

Collagen formation

Alcohol detoxification

Carbon dioxide elimination

Sexual maturation

Taste and smell functions

RDI: 3 mg for infants, 12 mg for adults and additional 4 mg/day duringpregnancy and lactation respectively


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Zinc

Deficiency:

Poor wound healing, subnormal growth, anorexia, abnormal

taste and smell, changes in hair, nails, skin inflammation,

anaemia, retarded development of the reproductive system


None

Toxicity:

May impair copper absorption - metallothionine


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Copper

Structure: complexes with proteins

Food Sources:

Liver, kidney, shellfish, whole grains, cherries, legumes, chocolate,

nuts, eggs, muscle meats, fish and poultry

Functions:

Required for proper use of iron by the body (ceruloplasmin)

Role in development of connective tissue, blood vessels

Synthesis of neurotransmitters (noradrenaline)

Cuproenzymes (oxidases)

RDI: No RDI in Australia; 1.0-1.5 mg/day is considered adequate


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Copper

Deficiency:

Anaemia, neutropenia, leukopenia, bone

demineralisation and failure of erythropoiesis

Therapeutic Effects:None

Toxicity:

None in healthy humans who eats natural foods

May reduce zinc absorption


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Selenium

Structure:

Selenoproteins

Sodium selenite

Food Sources:

Grains, meat, poultry, fish and dairy products

Functions:

Works with glutathione peroxidase to protect cells againstdestruction by hydrogen peroxide

Spare vitamin E

RDI: 70 g for females; 85 g for males; additional 5-10 g duringpregnancy and lactation


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Selenium

Deficiency:

Myalgia, cardiac myopathy (Keshans Disease)

Increased red blood cell fragility


None

Toxicity:

None


15/21

Iodine

Structure: Iodide salts and bound to proteins andlipids

Food Sources:

Iodized salt, salt water, seafood, sunflower

seeds, mushrooms, eggs, beef liver, peanuts,spinach, pumpkin, broccoli and chocolate

Functions:

Synthesis of thyroid hormones

Thyroxine and Tri-iodothyronine

RDI: 150 g/day for males; 120 g/day forfemales plus 30-50 g/day duringpregnancy/lactation
http://en.wikipedia.org/wiki/Image:Thyroxine.png


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Iodine

Deficiency:

Enlargement of thyroid gland, myxedema, cretinism, increase

in blood lipids


None

Toxicity:

Hyperthyroidism (thyrotoxicosis)

Japanese eating too much iodine-rich seaweed

Iodine supplementation as a treatment for goitre


17/21


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Chromium

Deficiency:

Glucose intolerance, abnormalities in glucose and lipid

metabolism, elevated circulating insulin, Syndrome X


Improve insulin resistance?

Fat metabolism?

Toxicity:

None


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Fluoride

Structure: as salts

Food Sources:

Mackerel, sardines, salt pork, salmon, shrimp, meat, sunflower

seeds, kale, potato, watercress, honey, wheat; drinking watercontent varies

Functions:

Maintenance of teeth and bone structure

RDI: None: drinking water may be fluoridated to 1 ppm


20/21

Fluoride

Deficiency:

Dental caries, osteoporosis

Therapeutic Effects:None

Toxicity:

Brittle bonesIncreased risk of fractures


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Other Trace Elements

Aluminium

No function

Alzheimer's disease

Molybdenum

Co-factor for urease enzyme

Cobalt

Vitamin B12

Arsenate

Vanadium

Silicon

nickel

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