Chapter 8

Minerals

1

Key Concepts

• The human body requires a variety of minerals to perform numerous metabolic tasks

• Inorganic substances

• Minerals = elements

2

Minerals

• Classes of minerals• Major minerals (recommended intake >100 mg/day)• Trace elements (<100 mg/day)

• Functions of minerals: Tissue building & metabolism• GROWTH & MAINTENANCE

3

Major Minerals

• Calcium >100mg/day• Phosphorus• Sodium• Potassium• Chloride• Magnesium• Sulfur

4

Calcium

• Functions• Bone and tooth formation• Muscle contraction• Nerve conduction

5

Calcium, cont’d

• Requirements• 1000 mg/day

• Deficiency states• Osteoporosis

• Toxicity symptoms – kidney stones• Food sources

• Milk is the major food source• Green vegetables, fish with bones, fortified food

6

Osteoporosis

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Phosphorus

• Functions• Bone and tooth formation, works with Calcium• Energy metabolism (releases energy from CHO, fat,

protein)• Maintain proper acid-base balance

8

Phosphorus, cont’d• Requirements

• 700 mg/day• Deficiency states – rare, widely available in foods• Toxicity: usually with renal disease

(hyperphosphatemia)• Food sources

• Milk, milk products, fish, eggs

9

Sodium

• Functions• Maintenance of water balance• Acid-base balance• Muscle action & transmission of nerve impulses

10

Sodium, cont’d• Requirements

• Recommended 1.5 - 2.3 g/day • *usual intake = 3500 mg/day

• Deficiency – rare strenuous exercise/diaphoresis, excess water intake: can lead to acid-

base imbalance, muscle cramps, neuro changes from low sodium (hyponatremia)

• Toxicity • Hypertension, especially w/ kidney disease

• Food sources - Table salt, cured meat, canned soups, processed food

11

Potassium

• Functions• Water balance• Blood pressure• Muscle action• Insulin release from beta cells (pancreas)

12

Potassium, cont’d• Requirements – no specific RDA

• *Amer. diet low 2-3 g/day• Deficiency – hypokalemia – muscle cramps• Toxicity – hyperkalemia, can cause severe heart arrythmias,

caution w/ kidney disease• Food sources

• Fruits, vegetables, whole grains, fresh meats• Oranges, bananas, tomatoes, potatoes, broccoli, leafy greens

13

Chloride

• Functions• Digestion

• Key element in hydrochloric acid secretion• Respiration – works with CO2 in maintaining acid

base balance

14

Chloride, cont’d

• Requirements – no specific RDA• AI: 2.3 g/day

• Deficiency – rare, excessive vomiting may result in acid/base imbalance

• Food sources• Table salt• Sea salt *both contain NaCl

15

Magnesium

• Functions• General metabolism

• Found in all body cells• Works with 300+ enzymes to produce energy

• Protein synthesis• Activates amino acids

• Muscle action – aids w/ nerve impulses, stimulation of muscle contraction

16

Magnesium, cont’d• Requirements

• ~300 to 400 mg/day (increases w/ age and preg)• Deficiency – rare, may be seen w/ vomiting &

starvation, can cause muscle cramping/weakness• Toxicity – rare, caution w/ kidney disease• Food sources - Nuts, soybeans, cocoa, seafood,

peas, green vegetables

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Trace Elements

• Iron• Iodine• Zinc• Selenium• Fluoride• Copper

18

• Manganese• Chromium• Molybdenum• Cobalt• Boron• Vanadium• Nickel

Iron

• Essential for life, but dangerous when in excess

• Functions• Hemoglobin synthesis (Hg carries O2 to cells)

• General metabolism• Proper glucose metabolism• Antibody production• Collagen synthesis• Conversion of beta-carotene to vitamin A

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Iron, cont’d• Requirements (increase w/ age and pregnancy)

• 8 to 11 mg/day for males• 8 to 18 mg/day for females

• Deficiency states• Anemia (decreased RBC’s)

• Toxicity – can be fatal• Hemochromatosis (iron overload – can cause organ

damage)• Food sources: meats, eggs, fortified cereals, liver,

better absorbed w/ Vit C

20

Iodine

• Functions• Participation in thyroid gland’s synthesis of thyroxine,

hormone required for metabolism• Requirements

• 150 mcg/day (minimum 50-75)

21

Iodine, cont’d• Deficiency states

• Goiter (enlarged thyroid gland)• Cretinism (dwarfism, MR – due to lack of iodine during

pregnancy)• Hypothyroidism (wt. gain, hair loss, dry skin, cold intolerance)• Hyperthyroidism – Graves disease (wt.loss, tremors,

nervousness/restless)

• Toxicity symptoms - rare• Food sources

• Iodized table salt, seafood

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Goiter

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Zinc

• Functions• Important during growth & pregnancy• Important for immune system

• Requirements• 11 mg/day for males• 8 mg/day for females

24

Zinc, cont’d

• Deficiency • Poor wound healing, hair loss• Impaired taste and smell• Dwarfism, impaired sexual maturation

• Toxicity – N/V w/ overuse• Food sources

• Meat, seafood, legumes, whole grains

25

Selenium

• Functions• Antioxidant, aids in protection from free radicals

• Requirements• RDA: 55 mcg/day• Brittle hair and nails w/ deficiency

• Food sources• Seafood, kidney, liver; depends on soil content

26

Other Trace Elements

• Fluoride•Functions by preventing dental carries

• Prevent cavities, hardens tooth enamel• Important for dental health

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Mineral Supplementation • Life cycle needs

• Pregnancy and lactation - need more Mg, Iron, Zinc, Iodine, Selenium

• Adolescence – more Ca and Phos• Adulthood – mineral supp not needed, balanced diet

is more important• Clinical needs

• Iron-deficiency anemia (adol, preg)• Zinc deficiency (vegetarians at risk)

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Applying Knowledge

The camp nurse gives a talk to the camp staff about the signs of fluid volume deficit. She encourages the counselors to be sure the campers drink fluids throughout the day. One counselor responds, “Oh, that’s no problem. The kids guzzle flavored ice tea all day long.” How should she respond?

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reserved. 29