Transcript Fundamentals of Nutrition - Brands Delmar

Chapter 8
Minerals
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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
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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
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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
(continues)
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Minerals
• Enriched foods
– Foods to which nutrients have been added to improve
nutritional value
• Usually B vitamins and iron
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Classification
• Major minerals
– Required in amounts greater than 100 mg per day
• Trace minerals
– Required in amounts smaller than 100 mg per day
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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
(continues)
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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
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Stop and Share
• Consider the following question:
– What is the best way to receive an adequate intake of
minerals?
(continues)
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Stop and Share
• Balanced diet
– Only safe way to include minerals in amounts necessary to
maintain health
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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
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Major Minerals
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Calcium (Ca)
Phosphorus (P)
Potassium (K)
Sodium (Na)
Chloride (Cl)
Magnesium (Mg)
Sulfur (S)
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Calcium
• More in human body than any other mineral
• In combination with phosphorus, gives
strength and hardness to bones and teeth
• Bones provide storage
(continues)
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Calcium
• Necessary for the following:
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Normal nerve and muscle action
Blood clotting
Heart function
Cell metabolism
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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
(continues)
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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
(continues)
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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
(continues)
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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
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Calcium Sources
• Milk and milk products
• Dark green leafy vegetables
– Oxalic acid in some vegetables prevents calcium from
being absorbed
(continues)
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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
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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
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Calcium Requirements
Age
Amount
0 to 6 months
6 to 12 months
1 to 3 years
4 to 8 years
9 to 18 years
19 to 50 years
51 to 70+ years
210 mg
270 mg
500 mg
800 mg
1,300 mg
1,000 mg
1,200 mg
(continues)
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Calcium Requirements
Age
Amount
Pregnant women:
14 to 18 years
1,300 mg
19 to 50 years
Lactating women:
1,000 mg
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.
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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
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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
(continues)
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Calcium Deficiency
• Osteoporosis causes brittle bones
• Tetany results from insufficient calcium in
blood
– Characterized by involuntary muscle movement
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Calcium Excess
• Excessive intake may do the following:
– Cause constipation
– Cause kidney stones
– Inhibit absorption of iron and zinc
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Phosphorus
• Constituent of all body cells
• Stored in bones
• Necessary for the following:
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Formation of strong, rigid bones and teeth
Metabolism of carbohydrates, fats, and proteins
Proper acid-base balance
Effective action of several B vitamins
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Phosphorus Sources
• Best sources:
– Milk, cheese, meats, poultry, and fish
• Other sources:
– Cereals, legumes, nuts, and soft drinks
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Phosphorus Absorption
• Increased in presence of vitamin D
• Excessive use of antacids can negatively affect
absorption
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Phosphorus Deficiency
• Rare
• Symptoms:
– Bone demineralization
– Fatigue
– Anorexia
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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
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Potassium Sources
• Fruits:
– Especially melons, oranges, bananas, and peaches
• Vegetables:
– Brussels sprouts, mushrooms, potatoes, tomatoes, winter
squash, lima beans, and carrots
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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
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Potassium Excess
• Hyperkalemia
• Caused by dehydration, renal failure, or
excessive intake
• Can result in cardiac failure
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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
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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
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Sodium Deficiency
• Caused by severe vomiting, diarrhea, and
heavy perspiration
– Leading to dehydration
• Can upset acid-base balance
– Causing acidosis or alkalosis
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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
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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
(continues)
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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
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Magnesium
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Vital to both hard and soft body tissues
Essential for metabolism
Regulates nerve and muscle function
Plays role in blood-clotting process
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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
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Magnesium Deficiency
• Unknown among people on normal diets
• Symptoms:
– Nausea and mental, emotional, and muscular disorders
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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
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Trace Minerals
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Iron (Fe)
Iodine (I)
Zinc (Zn)
Selenium (Se)
Copper (Cu)
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Manganese (Mn)
Fluoride (F)
Chromium (Cr)
Molybdenum (Mo)
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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
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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
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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
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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
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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
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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
(continues)
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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
(continues)
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Iodine
• Myxedema
– Condition of hypothyroidism in adults
• Cretinism
– Low thyroid in child
– Physical and mental development delayed
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Zinc
• Cofactor for more than 300 enzymes
• Essential for the following:
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Growth
Wound-healing
Taste acuity
Glucose tolerance
Mobilization of vitamin A within body
(continues)
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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
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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
(continues)
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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
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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
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Copper Sources
• Organ meats, shellfish, legumes, nuts, cocoa,
whole-grain cereals, and human milk
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Copper Deficiency
• Rare, but may occur in:
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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
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Copper Excess
• Highly toxic
• Wilson’s disease
– Inherited condition causing accumulation of copper in liver,
brain, kidneys, and cornea
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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
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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
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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
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Molybdenum
• Constituent of enzymes
• Considered to play role in metabolism
• Sources:
– Milk, liver, legumes, and cereals
• No deficiencies noted
• Excess inhibits copper absorption
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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
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