copyright © 2011 delmar, cengage learning. all rights reserved. chapter 8 minerals

Copyright © 2011 Delmar, Cengage Learning. ALL RIGHTS RESERVED.

Chapter 8

Minerals


Objectives

• Of the minerals discussed:– Identify at least two food sources of each mineral

– State one or more functions of each mineral

• Describe recommended method of avoiding mineral deficiencies


Facts

• Human body made up of specific chemical elements

• Oxygen, carbon, hydrogen, and nitrogen make up 96 percent of body weight

• Remaining elements and minerals represent 4 percent of body weight

• Essential for good health


Minerals

• Inorganic elements necessary to build tissues, regulate body fluids, and assist in various body functions

• Found in all body tissues

• Do not provide energy by themselves– But contribute to production of energy

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Minerals

• Enriched foods– Foods to which nutrients have been added to improve

nutritional value• Usually B vitamins and iron


Classification

• Major minerals– Required in amounts greater than 100 mg per day

• Trace minerals– Required in amounts smaller than 100 mg per day


Electrolytes

• Ions– Electrically charged atoms

• Resulting from mineral salts dissolved in water

– Cations• Positively charged

– Anions• Negatively charged

– Must be balanced within body

– Also known as electrolytes

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Electrolytes

• Maintain body’s fluid balance

• Contribute to electrical balance

• Assist in transmission of nerve impulses and contraction of muscles

• Help regulate body’s acid-base balance


Stop and Share

• Consider the following question:– What is the best way to receive an adequate intake of

minerals?

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Stop and Share

• Balanced diet– Only safe way to include minerals in amounts necessary to

maintain health


Toxicity

• Occurs when concentrated forms of minerals taken regularly over time

• Excessive amount of one mineral can lead to deficiency of another mineral

• Changes in nearly all tissues may result

• Concentrated minerals should be used only if prescribed


Major Minerals

• Calcium (Ca)

• Phosphorus (P)

• Potassium (K)

• Sodium (Na)

• Chloride (Cl)

• Magnesium (Mg)

• Sulfur (S)


Calcium

• More in human body than any other mineral

• In combination with phosphorus, gives strength and hardness to bones and teeth

• Bones provide storage

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Calcium

• Necessary for the following:– Normal nerve and muscle action

– Blood clotting

– Heart function

– Cell metabolism


Calcium Regulation

• Hormonal system regulates delivery to cells

• Parathyroid glands release hormone telling kidneys to retrieve calcium before it is excreted when blood calcium levels drop

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Calcium Regulation

• Hormone works with calcitriol– Causing increased release of calcium from bones by

stimulating activity of osteoclasts

• Both actions increase blood calcium levels

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Calcium Regulation

• Every cell needs calcium

• Normal blood calcium levels maintained even if intake poor

• Bones become increasingly fragile as calcium withdrawn

• Osteoporosis may result from years of low calcium intake

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Calcium Regulation

• Osteoblasts increase bone mass if blood calcium level high until age 30 to 35

• Bone mass remains stable in women with adequate consumption of calcium, phosphorus, and vitamin D– Until menopause


Calcium Sources

• Milk and milk products

• Dark green leafy vegetables– Oxalic acid in some vegetables prevents calcium from

being absorbed

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Calcium Sources

• Fiber intake of more than 35 g per day causes calcium to bind with phytates– Also limits absorption

– Phytates• Phosphorus compounds found in some high-fiber cereals


Calcium Absorption

• Items that enhance absorption:– Vitamin D

– Calcium-to-phosphorus ratio that includes no more phosphorus than calcium

– Presence of lactose

• Items that retard absorption:– Lack of weight-bearing exercise


Calcium Requirements

Age Amount0 to 6 months 210 mg

6 to 12 months 270 mg

1 to 3 years 500 mg

4 to 8 years 800 mg

9 to 18 years 1,300 mg

19 to 50 years 1,000 mg

51 to 70+ years 1,200 mg

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Calcium Requirements

Age AmountPregnant women:

14 to 18 years 1,300 mg

19 to 50 years 1,000 mg

Lactating women:

Same as non-lactating women of same age

Source:Dietary Reference Intakes: The Essential Guide to Nutrient Requirements © 2006 by the National Academy of Sciences, Courtesy of the National Academies Press, Washington, D.C.


Calcium Supplements

• Calcium carbonate has highest concentration of bioavailable calcium

• Absorbed most efficiently when consumed in doses of 500 mg

• Check for United States Pharmacopeia (USP)-approved products– Unlikely to contain lead


Calcium Deficiency

• Rickets results in poorly formed bone structure– Causes bowed legs, “pigeon breast,” enlarged wrists or

ankles, and stunted growth

• “Adult rickets” causes bones to become soft– Also known as osteomalacia

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Calcium Deficiency

• Osteoporosis causes brittle bones

• Tetany results from insufficient calcium in blood– Characterized by involuntary muscle movement


Calcium Excess

• Excessive intake may do the following:– Cause constipation

– Cause kidney stones

– Inhibit absorption of iron and zinc


Phosphorus

• Constituent of all body cells

• Stored in bones

• Necessary for the following:– Formation of strong, rigid bones and teeth

– Metabolism of carbohydrates, fats, and proteins

– Proper acid-base balance

– Effective action of several B vitamins


Phosphorus Sources

• Best sources:– Milk, cheese, meats, poultry, and fish

• Other sources:– Cereals, legumes, nuts, and soft drinks


Phosphorus Absorption

• Increased in presence of vitamin D

• Excessive use of antacids can negatively affect absorption


Phosphorus Deficiency

• Rare

• Symptoms:– Bone demineralization

– Fatigue

– Anorexia


Potassium

• Found primarily in intracellular fluid

• Essential with sodium for fluid balance and osmosis

• Maintains fluid level within cell

• Necessary for the following:– Transmitting nerve impulses and muscle contractions


Potassium Sources

• Fruits:– Especially melons, oranges, bananas, and peaches

• Vegetables:– Brussels sprouts, mushrooms, potatoes, tomatoes, winter

squash, lima beans, and carrots


Potassium Deficiency

• Hypokalemia

• Caused by diarrhea, vomiting, diabetic acidosis, severe malnutrition, or excessive use of laxatives or diuretics

• Symptoms:– Nausea, anorexia, fatigue, muscle weakness, and heart

abnormalities


Potassium Excess

• Hyperkalemia

• Caused by dehydration, renal failure, or excessive intake

• Can result in cardiac failure


Sodium

• Primarily necessary for the following:– Control of fluid balance in body

• Maintains acid-base balance

• Participates in transmission of nerve impulses essential for normal muscle function


Sodium Sources

• Table salt contains 40 percent– One teaspoon contains 2,000 mg

• Naturally available in animal foods

• DRI of 1,500 mg

• Tolerable upper limit of 5,800 mg– Easily exceeded by general population


Sodium Deficiency

• Caused by severe vomiting, diarrhea, and heavy perspiration– Leading to dehydration

• Can upset acid-base balance– Causing acidosis or alkalosis


Sodium Excess

• May cause edema– Resulting in hypertension

• Associated with hypertension and congestive heart failure

• Treatment:– Sodium-restricted diet

• Diets below 1 g rarely prescribed


Chloride

• Essential for the following:– Maintenance of fluid, electrolyte, and acid-base balance

• Found in hydrochloric acid, cerebrospinal fluid, and muscle and nerve tissue

• Helps blood carry carbon dioxide to lungs

• Necessary during immune responses when WBCs attack foreign cells

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Chloride

• Found almost exclusively in table salt or in foods containing sodium chloride

• Deficiency rare

• Can occur with severe vomiting, diarrhea, excessive use of diuretics, and alkalosis


Magnesium

• Vital to both hard and soft body tissues

• Essential for metabolism

• Regulates nerve and muscle function

• Plays role in blood-clotting process


Magnesium Sources

• Found primarily in plant foods

• Green leafy vegetables, legumes, nuts, whole grains, some fruits (e.g., avocados, bananas), and milk in sufficient quantities


Magnesium Deficiency

• Unknown among people on normal diets

• Symptoms:– Nausea and mental, emotional, and muscular disorders


Sulfur

• Necessary to all body tissue and for metabolism

• Contributes to characteristic odor of burning hair and tissue

• Component of some amino acids

• Found in protein-rich foods

• Both amount required by human body and deficiency unknown


Trace Minerals

• Iron (Fe)• Iodine (I)• Zinc (Zn)• Selenium (Se)• Copper (Cu)

• Manganese (Mn)• Fluoride (F)• Chromium (Cr)• Molybdenum (Mo)


Iron

• Delivers oxygen to body tissues

• Component of hemoglobin

• Component of myoglobin– Protein compound in muscles that provides oxygen to cells

• Used by enzymes involved in making amino acids, hormones, and neurotransmitters


Iron Sources

• Heme iron:– Meat, poultry, and fish

– Absorbed more than twice as efficiently as nonheme iron

• Nonheme iron:– Whole-grain cereals, enriched grain products, vegetables,

fruits, eggs, meat, fish, and poultry


Iron Requirements

• RDA doubles during pregnancy– Difficult to meet by diet alone

– Iron supplement commonly prescribed

• Increased requirements during infancy and teenage years

• Vitamin C enhances absorption


Iron Deficiency

• Caused by insufficient intake, malabsorption, lack of stomach acid, or excessive blood loss

• Iron-deficiency anemia– Most common nutrient deficiency worldwide

• Symptoms:– Fatigue, weakness, irritability, shortness of breath, pale

skin, and spoon-shaped fingernails


Iron Excess

• Hemochromatosis– Results from inborn error of metabolism that causes

excessive absorption of iron

– Untreated, can damage liver, spleen, and heart

– To control iron buildup, must give blood on regular basis


Iodine

• Component of thyroid hormones, thyroxine (T4), and triiodothyronine (T3)

• Necessary for the following:– Normal functioning of thyroid gland

• Determines rate of metabolism

• Sources:– Iodized salt, seafood, and some plant foods grown in soil

bordering sea

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Iodine

• Increased requirements during pregnancy and lactation

• Deficiencies:– Cause decrease in thyroxine and triiodothyronine

– Gland grows, forming lump on neck• Goiter

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Iodine

• Myxedema– Condition of hypothyroidism in adults

• Cretinism– Low thyroid in child

– Physical and mental development delayed


Zinc

• Cofactor for more than 300 enzymes

• Essential for the following:– Growth

– Wound-healing

– Taste acuity

– Glucose tolerance

– Mobilization of vitamin A within body

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Zinc

• Sources:– Meat, fish, eggs, dairy products, wheat germ, and legumes

• Increased requirements during pregnancy and lactation

• Deficiency symptoms:– Decreased appetite and taste acuity, delayed growth,

dwarfism, hypogonadism, poor wound-healing, anemia, acne-like rash, and impaired immune response


Selenium

• Constituent of most body tissues

• Concentrated in liver, kidneys, and heart

• Component of enzyme that acts as antioxidant– Protects cells against oxidation

– Spares vitamin E

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Selenium

• Sources:– Seafood, kidney, liver, and muscle meats

• High doses toxic– Causes vomiting, loss of hair and nails, and skin lesions


Copper

• In all tissues– Heaviest concentration in liver, kidneys, muscles, and brain

• Helps with the following:– Formation of hemoglobin

– Transportation of iron to bone marrow for RBC formation

– Production of energy


Copper Sources

• Organ meats, shellfish, legumes, nuts, cocoa, whole-grain cereals, and human milk


Copper Deficiency

• Rare, but may occur in:– Malabsorption conditions

– Gross protein deficiency

– Premature infants

– Clients on long-term parenteral nutrition

– People taking excess zinc supplements

• May cause anemia, bone demineralization, and impaired growth


Copper Excess

• Highly toxic

• Wilson’s disease– Inherited condition causing accumulation of copper in

liver, brain, kidneys, and cornea


Manganese

• Constituent of several enzymes involved in metabolism

• Important in bone formation

• Sources:– Whole grains, teas, vegetables, and fruits

• Deficiency or toxicity from ingestion unknown

• Inhalation linked to neurological problems


Fluoride

• Increases resistance to dental caries– May strengthen teeth and bones

• Sources:– Fluoridated water, fish, and tea and commercially prepared

foods with fluoridated water

• Deficiency can result in increased tooth decay

• Excess can cause permanent discoloration or mottling of children’s teeth


Chromium

• Associated with glucose and lipid metabolism

• Levels decrease with age except in lungs– Where it accumulates

• Sources:– Meat, mushrooms, nuts, yeast, organ meats, and wheat

germ

• Deficiency related to disturbances in glucose metabolism


Molybdenum

• Constituent of enzymes

• Considered to play role in metabolism

• Sources:– Milk, liver, legumes, and cereals

• No deficiencies noted

• Excess inhibits copper absorption


Conclusion

• Megadoses of minerals dangerous

• Minerals necessary to promote growth and regulate body processes

• Minerals originate in soil and water and ingested via food and drink

• Deficiencies can result in severe conditions

• Excess can be toxic

copyright © 2011 delmar, cengage learning. all rights reserved. chapter 8 minerals

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concentrated minerals

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sulfur s slide