Transcript Fundamentals of Nutrition

Section 1
Fundamentals of Nutrition
Copyright © 2003 Delmar Learning, a Thomson Learning company
Chapter 8
Minerals
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Objectives
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List at least two food sources of given
minerals
List one or more functions of given
minerals
Describe the 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% of body weight.
Remaining elements, minerals, represent
4% of body weight.
Minerals are essential for good health.
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Facts
Inorganic elements are necessary to build
tissues, regulate body fluids, and assist in
various body functions.
Found in all body tissues.
Cannot provide energy by themselves.
Contribute to production of energy within
the body.
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Facts
Enriched foods are foods to which
nutrients, usually B vitamins and iron,
have been added to improve their
nutritional value.
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Classification
Major minerals
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Required in amounts greater than 100
mg a day
Trace minerals
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Chapter 8
Needed in amounts smaller than 100 mg
a day
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Electrolytes
Ions
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Electrically charged atoms resulting
from chemical reactions
Positively charged called cations
Negatively charged called anions
Must be balanced within body
These ions are known as electrolytes
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Electrolytes
Maintain the body’s fluid balance,
contribute to electrical balance, assist in
transmission of nerve impulses and
contraction of muscles, help regulate the
body’s acid-base balance.
Chapter 8
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Stop and Share
What is the best way to receive an
adequate intake of minerals?
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Stop and Share
A balanced diet is the only safe way of
including minerals in the amounts
necessary to maintain health!
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Toxicity
Toxicity occurs when concentrated forms
of minerals are taken regularly over time.
Excessive amount of one mineral may lead
to deficiency of another mineral.
Hair loss and changes in blood, hormones,
bones, muscles, blood vessels, and nearly
all tissues may result.
Concentrated minerals only if prescribed.
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Major minerals
Calcium, Phosphorus, Potassium, Sodium,
Chloride
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Calcium (Ca)
Human body contains more calcium than
any other mineral.
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99% found in skeleton and teeth
1% found in blood
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Calcium: Functions
In combination with phosphorus, gives
strength and hardness to bones and teeth.
Bones provide storage for calcium.
Needed for normal nerve and muscle
action, blood clotting, heart function, and
cell metabolism.
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Calcium: Regulation
Hormonal system regulates delivery of
calcium to cells.
Every cell needs calcium and normal blood
calcium levels are maintained even if
intake is poor.
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Calcium: Regulation
Parathyroid glands release a hormone
telling the kidneys to retrieve calcium
before it is excreted when blood calcium
levels drop.
This 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
Bones become increasingly fragile as
calcium is withdrawn from them.
Osteoporosis may result from years of low
calcium intake.
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Calcium: Regulation
Osteoblasts increase bone mass if blood
calcium level is high until one is age 30-35
years old.
Bone mass will remain stable in women
until menopause with adequate
consumption of calcium, phosphorus, and
vitamin D.
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Calcium: Sources
Milk and milk products
Dark green, leafy vegetables
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When vegetables contain oxalic acid, as
spinach and Swiss chard do, the calcium
remains unavailable because the oxalic
acid binds it and prevents it from being
absorbed
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Calcium: Sources
Fiber
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Chapter 8
When the intake of fiber exceeds 35g a
day, calcium will also bind with phytates
(phosphorus compounds found in some
high-fiber cereal), which also limits its
absorption
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Calcium: Sources
Enhances absorption of calcium
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Vitamin D
Calcium-to-phosphorus ratio that
includes no more phosphorus than
calcium
Presence of lactose
Retards absorption
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Lack of weight-bearing exercise
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Calcium: Requirements
0-6 months
6-12 months
1-3 years
4-8 years
9-18 years
19-50 years
51-70+ years
Chapter 8
210 mg
270 mg
500 mg
800 mg
1,300 mg
1,000 mg
1,200 mg
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Calcium: Requirements
Pregnant women
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14-18 years
19-50 years
1,300 mg
1,000 mg
Lactating women same as nonlactating
women of same age
Source: Dietary Reference Intakes, Food and Nutrition Board,
National Academy of Sciences-Institute of Medicine, 1997
Chapter 8
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Calcium: Supplements
Calcium carbonate, form found in calciumbased antacid tablets, has highest
concentration of bioavailable calcium.
Appear to be absorbed most efficiently
when consumed in doses of 500 mg.
Check for USP-approved products, which
are unlikely to contain lead.
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Calcium: Supplements
Chapter 8
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Calcium: Deficiency
Rickets results in poorly formed bone
structure and causes bowed legs, “pigeon
breast”, enlarged wrists or ankles, and
stunted growth.
“Adult rickets” (osteomalacia) causes
bones to become soft.
Tetany, characterized by involuntary muscle
movement, results from insufficient calcium
in blood.
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Calcium: Excess
Excessive intake may:
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Cause constipation
Cause kidney stones
Inhibit the absorption of iron and zinc
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Phosphorus (P)
Constituent of all body cells.
Necessary for the formation of strong,
rigid bones and teeth; metabolism of
carbohydrates, fats, and proteins; proper
acid-base balance; and effective action of
several B vitamins.
Stored in bones, absorption is increased in
the presence of vitamin D.
Chapter 8
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Phosphorus: Sources
Protein-rich foods such as milk, cheese,
meats, poultry, and fish.
Cereals, legumes, nuts, soft drinks
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Phosphorus: Requirements
Adequate Intake
0-6 months
100 mg
6-12 months
275 mg
Estimated Average Requirements
1-3 years
380 mg
4-8 years
405 mg
9-18 years
1,055 mg
Chapter 8
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Phosphorus: Requirements
19-70+ years
580 mg
Pregnant and
Same as for
lactating women nonpregnant and
nonlactating women
Source: Dietary Reference Intakes, Food and Nutrition
Board, National Academy of Sciences-Institute of
Medicine, 1997
Chapter 8
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Phosphorus: Deficiency
Deficiency is rare.
Excessive use of antacids affect
absorption.
Symptoms of deficiency include bone
demineralization (loss of minerals),
fatigue, and anorexia.
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Potassium (K)
Found primarily in intracellular fluid.
Essential for fluid balance and osmosis.
Maintains fluid level within the cell.
Necessary for transmitting nerve impulses
and muscle contractions.
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Potassium: Sources
Fruits–especially melons, oranges,
bananas, peaches
Vegetables–mushrooms, brussel sprouts,
potatoes, tomatoes, winter squash, lima
beans, carrots
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Potassium: Deficiency
Hypokalemia
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Caused by diarrhea, vomiting, diabetic
acidosis, severe malnutrition, or
excessive use of laxatives or diuretics
Symptoms of deficiency include nausea,
anorexia, fatigue, muscle weakness,
heart abnormalities
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Potassium: Excess
Hyperkalemia
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Chapter 8
Caused by dehydration, renal failure,
excessive intake
Cardiac failure can result
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Sodium
Primary function is the control of fluid
balance in the body.
Maintains acid-base balance.
Participates in the transmission of nerve
impulses essential for normal muscle
function.
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Sodium: Sources
Table salt contains 40% sodium.
One teaspoon of table salt contains 2,000
mg of sodium.
Naturally available in animal foods.
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Sodium: Requirements
0-5 months
6-11 months
1 year
2-5 years
6-9 years
10-18 years
> 18 years
120 mg
200 mg
225 mg
300 mg
400 mg
500 mg
500 mg
Recommended Dietary Allowances: 10th Edition. Copyright 1989 by the
National Academy of Sciences. Courtesy of the National Academy Press,
Washington, D.C.
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Sodium: Deficiency
Caused by severe vomiting, diarrhea, and
heavy perspiration.
Can upset the acid-base balance.
Tetany due to alkalosis may develop.
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Sodium: Excess
May cause edema and resulting
hypertension.
Associated with hypertension and
congestive heart failure.
Treatment includes sodium-restricted diets;
3-4g (no-added salt, or NAS) or 1-2g
sodium-restricted diet. Diets below 1g
rarely prescribed.
Chapter 8
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Chloride (Cl)
Essential for 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 the
lungs and is necessary during immune
responses when white blood cells attack
foreign cells.
Chapter 8
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Chloride
Found almost exclusively in table salt or in
foods containing sodium chloride.
Estimated minimum requirement for
normal adults is 750 mg a day.
Deficiency is rare.
Can occur with severe vomiting, diarrhea,
excessive use of diuretics, and alkalosis.
Chapter 8
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Magnesium (Mg)
Vital to both hard and soft body tissues.
Essential for metabolism.
Regulates nerve and muscle function.
Plays a role in the blood-clotting process.
Chapter 8
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Magnesium: Sources
Found primarily in plant foods.
Green leafy vegetables, legumes, nuts,
whole grains, some fruits (avocados and
bananas)
Milk in sufficient quantities
Chapter 8
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Magnesium: Requirements
Adequate Intake
0-6 months
6-12 months
Boys and girls 1-3 years
4-8 years
9-13 years
Chapter 8
30 mg
75 mg
80 mg
130 mg
240 mg
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Magnesium: Requirements
Boys
Girls
Men
Women
Men
Women
Chapter 8
14-18 years
14-18 years
19-30 years
19-30 years
31-70+ years
31-70+ years
410 mg
360 mg
400 mg
310 mg
420 mg
320 mg
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Magnesium: Requirements
Pregnant women
14-18 years
19-30 years
31-50 years
Lactating women 14-18 years
19-30 years
31-50 years
400 mg
350 mg
360 mg
360 mg
310 mg
320 mg
Dietary Reference Intakes, Food and Nutrition Board, National
Academy of Sciences-Institute of Medicine, 2001.
Chapter 8
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Magnesium: Deficiency
Deficiency among people on normal diets
is unknown.
Experimentally induced symptoms include
nausea, mental, emotional, muscular
disorders.
Chapter 8
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Sulfur (S)
Necessary to all body tissue and is found
in all body cells.
Contributes to the characteristic odor of
burning hair and tissue.
Necessary for metabolism.
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Sulfur
Component of some amino acids.
Found in protein-rich foods.
Neither the amount of sulfur required by
the human body nor its deficiency is
known.
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Trace minerals
Iron, Iodine, Zinc, Selenium, Copper,
Manganese, Fluoride, Chromium,
Molybdenum
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Iron (Fe)
Delivers oxygen to body tissues.
Component of hemoglobin.
Component of myoglobin, a protein
compound in muscles that provides
oxygen to cells.
Utilized by enzymes that are involved in
making amino acids, hormones, and
neurotransmitters.
Chapter 8
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Iron: Sources
Meat, poultry, and fish are the best sources
of iron. Animal flesh contains heme iron,
which is absorbed more than twice as
efficiently as nonheme iron.
Nonheme iron is found in whole grain
cereals, enriched grain products,
vegetables, fruit, eggs, meat, fish, and
poultry.
Chapter 8
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Factors that Affect Iron
Absorption
Chapter 8
Increase
Decrease
Acid in the stomach
Heme iron
High body demand for
red blood cells (blood
loss, pregnancy)
Phytic acid (in fiber)
Oxalic acid
Polyphenols in tea and
coffee
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Factors that Affect Iron
Absorption
Chapter 8
Increase
Decrease
Low body stores of
iron
Meat protein factor
(MPF)
Vitamin C
Full body stores of iron
Excess of other
minerals (Zn, Mn, Ca)
Some antacids
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Iron: Requirements
Men lose approximately 1 mg/day.
Women lose approximately 1.5 mg/day.
RDA for men is 10 mg, and for women age
eleven through childbearing is 15 mg.
RDA doubled during pregnancy; difficult
to meet by diet alone.
Iron supplement commonly prescribed
during pregnancy.
Heavy need during infancy and teens.
Chapter 8
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Iron: Deficiency
Caused by insufficient intake,
malabsorption, lack of stomach acid, or
excessive blood loss.
Most common nutrient deficiency
worldwide is iron-deficiency anemia.
Symptoms include fatigue, weakness,
irritability, shortness of breath, pale skin,
and spoon-shaped fingernails.
Chapter 8
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Iron: Excess
Hemochromatosis is a condition due to an
inborn error of metabolism and causes
excessive absorption of iron.
Untreated, can damage liver, spleen, heart.
To control buildup of iron, patients with
this condition must give blood on a regular
basis.
Chapter 8
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Iodine (I)
Component of thyroid hormones,
thyroxine (T4) and triiodothyronine (T3).
Necessary for the normal functioning of
thyroid gland, which determines rate of
metabolism.
Sources include iodized salt, seafood, and
some plant foods grown in soil bordering
the sea.
Chapter 8
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Iodine
RDA for adults is 150 g a day.
Additional amounts needed during
pregnancy and lactation.
Lack of iodine results in decrease in
thyroxine and triiodothyronine.
Gland grows, forming a lump on the neck
called a goiter.
Chapter 8
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Iodine
Myxedema is a condition of hypothyroidism
in adults.
Cretinism is low thyroid in a child; retards
physical and mental development.
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Zinc (Zn)
Cofactor for more than 300 enzymes.
Essential for growth, wound healing, taste
acuity, glucose tolerance, and mobilization
of vitamin A within the body.
Sources include meat, fish, eggs, dairy
products, wheat germ, and legumes.
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Zinc
RDA for normal adult males is 11 mg.
RDA for normal adult females is 8 mg.
Increased requirements during pregnancy
and lactation.
Symptoms of deficiency include decreased
appetite, taste acuity, delayed growth,
dwarfism, hypogonadism, poor wound
healing, anemia, acnelike rash, impaired
immune response.
Chapter 8
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Selenium (Se)
Constituent of most body tissues.
Concentrated in liver, kidneys, and heart.
Component of an enzyme that acts as an
antioxidant, thereby protecting cells
against oxidation and sparing vitamin E.
Sources include seafood, kidney, liver,
muscle meats.
Chapter 8
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Selenium (Se)
RDA for adult male is 70 g.
RDA for adult female is 55 g.
Selenium supplements appear to be
effective in treating Keshan disease
High doses are toxic causing vomiting,
loss of hair and nails, and skin lesions.
Chapter 8
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Copper (Cu)
Found in all tissues; heaviest concentration
in the liver, kidneys, muscles, and brain.
Helps in formation of hemoglobin; aids in
transport of iron to bone marrow for the
formation of red blood cells; and
participates in energy production.
Chapter 8
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Copper (Cu)
Sources include organ meats, shellfish,
legumes, nuts, cocoa, whole grain cereals,
and human milk.
No RDA; NRC’s estimated safe intake for
adults is 1.5-3 mg/day.
Chapter 8
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Copper (Cu)
Deficiency is rare.
People with malabsorption conditions and
gross protein deficiency such as premature
infants; clients on long-term parenteral
nutrition programs lacking copper; and
people taking excess zinc supplements are
candidates for deficiency.
Anemia, bone demineralization, and
impaired growth may result.
Chapter 8
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Copper (Cu)
Excess is highly toxic.
Single dose of 10-15 mg can cause
vomiting.
Wilson’s disease is an inherited condition
causing damage to liver cells and neurons.
Detected early, copper-binding agents may
be used to bind copper in bloodstream and
increase excretion.
Chapter 8
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Manganese (Mn)
Constituent of several enzymes involved in
metabolism.
Important in bone formation.
Sources include whole grains, tea,
vegetables, and fruits.
Adequate intake is 2.3 mg for men and 1.8
mg for women.
No deficiency/toxicity from ingestion
known.
Inhalation linked to neurological problems.
Chapter 8
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Fluoride (F)
Increases resistance to dental caries, and
may strengthen teeth and bones.
Sources include fluoridated water, fish and
tea. Commercially prepared foods with
fluoridated water.
Deficiency can result in increased tooth
decay.
Excess can cause discoloration or mottling
of children’s teeth.
Chapter 8
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Fluoride: Requirements
Boys
Chapter 8
0-6 months
6-12 months
1-3 years
4-8 years
9-13 years
14-18 years
.01 mg
0.5 mg
0.7 mg
1.0 mg
2.0 mg
3.1 mg
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Fluoride: Requirements
Girls
Males
Females
14-18 years
19+ years
19+ years
3.0 mg
4.0 mg
3.0 mg
Pregnant and
Same as nonpregnant
lactating women and nonlactating
women of same age
Dietary Reference Intakes, Food and Nutrition Board,
National Academy of Sciences-Institute of Medicine, 1997.
Chapter 8
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Chromium (Cr)
Associated with glucose and lipid
metabolism.
Levels decrease with age except in lungs,
where chromium accumulates.
Sources include meat, mushrooms, nuts,
yeast, organ meats, and wheat germ.
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Chromium (Cr)
Safe and adequate daily intake for men is
35 μg and women 25 μg
Deficiency related to disturbances in
glucose metabolism.
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Molybdenum (Mo)
Constituent of enzymes, and thought to
play a role in metabolism.
Sources include milk, liver, legumes, and
cereals.
Safe and adequate daily intake for adults is
45 g.
No deficiencies noted.
Excess inhibits copper absorption.
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Conclusion
Megadoses of minerals are dangerous.
Minerals are necessary to promote growth
and regulate body processes.
Originate in soil and water and ingested
via food and drink.
Deficiencies can result in anemia, rickets,
and goiter.
Excess can be toxic resulting in hair loss
and changes in nearly all body tissues.
Chapter 8
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