MINERALS
As a nutrient category minerals are elemental substances
other than Carbon, Hydrogen, Oxygen, and Nitrogen.
Therefore, they are inorganic.
 They represent ~5% of your total body weight.
 They are essential nutrients – can only be obtained from
food and water. They originate from rocks and make
their way into water, soil and eventually plants and
animals.
 Their function is regulatory and structural
 There are two major classifications of minerals
o Macrominerals – e.g. Calcium, Sodium, Potassium,
etc.
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o These are required in amounts greater than
100mg/day
o Trace (Micro) minerals – e.g. Iron, Zinc, Iodine,
Fluoride, etc.
o These are required in amounts less than 50mg/day.
 Bioavailability – the amount or proportion of a nutrient
that is available for absorption. For Protein,
Carbohydrates, and Fats, bioavailability is about 9095%. For minerals, it ranges from a low value of 5%
bioavailability of iron from spinach, to over 60% for
sodium from foods like snack crackers. Bioavailability is
taken into consideration when setting RDA requirements
for nutrients.
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MACROMINERALS
1. Calcium – Accounts for about 2% of body weight – 99%
of which is in teeth and bones. The other 1% is found in
body tissues and is important for blood clot formation and
muscle and nerve cell impulse transmission.
 Tissue levels must be kept constant (homeostasis)
regardless of how much is supplied in the diet
o Robs the bones of calcium
o Bioavailability of dietary calcium increases
o Excretion of calcium is reduced
Leaching of calcium from bones results in decreased
mineralization of the bones (osteoporosis, osteomalacia,
rickets in children)
 Vitamin D needed for calcium absorption
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2. Sodium & Potassium
Work closely together to regulate fluid balance
(homeostasis). Different proportions of these minerals
inside and outside the cells.
 Fluid regulation
 Transmission of nerve impulses
 Deficiency – rare except in cases of rapid fluid loss
o Symptoms – low blood pressure, dizziness, muscle
weakening, cramping, nausea.
 1:3 ratio of Na+ to K+ may be an issue (high blood
pressure)
 Excessive intakes of sodium common….
 Potassium lost in processing of foods
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TRACE (MICRO) MINERALS
1. Iron
 part of oxygen-carrying protein called hemoglobin.
 Serves as an enzyme-helper (co-factor) in energy
metabolism
 Homeostasis of iron maintained by:
o Minimizing excretion of iron
o Recycling iron from dead blood cells
o Adapting bioavailability through increased
absorption of iron in the small intestine
o Maintaining iron ‘stores’
 Deficiency – common in young adolescent women
o Iron-deficient anemia
o Fatigue – due to lack of O2 to cells
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 Bioavailability affected by:
o How great your need is
o Form of iron in food – meat (heme) vs. non-meat
(non-heme) being 20-30% vs. 5-10%.
o Meal composition or food factors
 Vitamin C increases non-heme iron absorption
 Fibre (>50g) can decrease “
“
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 Tannins found in tea, etc. can decrease iron
absorption
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2. Zinc
 Helps with new cell production – therefore very
important for growth and development (pregnancy,
childhood, puberty)
 Helps body make proteins, heal wounds and form blood
 Important for sexual maturation
 Deficiency
o Delayed sexual development
o Impaired immune function
o Decreased taste perception (esp. in elderly)
3. Iodine
 Incorporated into hormones made by thyroid gland
which direct oxygen use by cells
o Energy use (BMR)
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o Reproductive function
o Growth
 Deficiency – results from eating foods grown in iodinedeficient soil
o Decreased production of thyroid hormones
o Low energy levels, weight gain (BMR lowered)
o Goiter (enlarged thyroid gland), cretinism
4. Fluoride
 Structure of teeth/bones
 Helps teeth resist decay
 Deficiency – higher incidence of tooth decay
 Toxicity – fluorosis (mottled teeth)
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