Summary of Chapter 9 – Water and the Minerals
Water makes up about 60 percent of the body’s weight. Water helps transport nutrients and waste products throughout the body,
participates in metabolic reactions, acts as a solvent, assists in maintaining blood pressure and body temperature, acts as a lubricant and
cushion around joints, and serves as a shock absorber. To maintain water balance, intake from liquids, foods, and metabolism must equal
losses from kidneys, skin, lungs, and feces. Electrolytes help maintain the appropriate distribution of body fluids and help to maintain
acid-base balance as well.
All of the major minerals influence the body’s fluid balance, but sodium, chloride, and potassium are most noted for this role. Excess
sodium in the diet contributes to high blood pressure. Most of the body’s calcium is in the bones, where it provides a rigid structure and a
reservoir of calcium for the blood.
The body requires trace minerals in tiny amounts, and they function in similar ways—assisting enzymes all over the body. Eating a diet
that consists of a variety of foods is the best way to ensure an adequate intake of these important nutrients. Many dietary factors,
including the trace minerals themselves, affect the absorption and availability of these nutrients.
Mineral Name
Chief Functions
Deficiency Symptoms
Toxicity Symptoms
Significant Sources
Sodium
With chloride and
potassium
(electrolytes), maintains
cells’ normal fluid
balance and acid-base
balance in the body.
Also critical to nerve
impulse transmission.
Muscle cramps, mental
apathy, loss of appetite
Hypertension
Salt, soy sauce,
processed foods
Chloride
Part of the hydrochloric
acid found in the
stomach and necessary
for proper digestion.
Growth failure in
children; muscle
cramps, mental apathy,
loss of appetite; can
cause death
(uncommon).
Normally harmless (the
gas chlorine is a poison
but evaporates from
water); can cause
vomiting.
Salt, soy sauce;
moderate quantities in
whole, unprocessed
foods, large amounts in
processed foods
Potassium
Facilitates reactions,
including the making of
protein; the
maintenance of fluid
and electrolyte balance;
the support of cell
integrity; the
transmission of nerve
impulses; and the
contraction of muscles,
including the heart.
Deficiency
accompanies
dehydration; causes
muscular weakness,
paralysis, and
confusion; can cause
death.
Causes muscular
weakness; triggers
vomiting; if given into a
vein, can stop the
heart.
All whole foods: meats,
milk, fruits, vegetables,
grains, legumes
Calcium
The principal mineral of
bones and teeth. Also
acts in normal muscle
contraction and
relaxation, nerve
functioning, blood
clotting, blood pressure,
and immune defenses.
Stunted growth in
children; adult bone
loss (osteoporosis)
Constipation; increased
risk of urinary stone
formation and kidney
dysfunction;
interference with
absorption of other
minerals.
Milk and milk products,
oysters, small fish (with
bones), tofu (bean
curd), greens, legumes
Phosphorus
Important in cells’
genetic material, in cell
membranes as
phospholipids, in
energy transfer, and in
buffering systems.
Phosphorus deficiency
unknown
Excess phosphorus
may cause calcium
excretion.
All animal tissues
Magnesium
Another factor involved
in bone mineralization,
the building of protein,
enzyme action, normal
muscular contraction,
transmission of nerve
Weakness; confusion; if
extreme, convulsions,
bizarre movements
(especially of eyes and
face), hallucinations,
and difficulty in
Large doses taken in
the form of the laxative
Epsom salts cause
diarrhea.
Nuts, legumes, whole
grains, dark green
vegetables, seafoods,
chocolate, cocoa
impulses, and
maintenance of teeth.
swallowing. In children,
growth failure.
Sulfur
A component of certain
amino acids; part of the
vitamins biotin and
thiamin and the
hormone insulin;
combines with toxic
substances to form
harmless compounds;
stabilizes protein shape
by forming sulfur-sulfur
bridges.
None known; protein
deficiency would occur
first.
Would occur only if
sulfur amino acids were
eaten in excess; this (in
animals) depresses
growth.
All protein-containing
foods
Mineral Name
Chief Functions
Deficiency Symptoms
Toxicity Symptoms
Significant Sources
Iron
Part of the protein
hemoglobin, which
carries oxygen in the
blood; part of the
protein myoglobin in
muscles, which makes
oxygen available for
muscle contraction;
necessary for the
utilization of energy.
Anemia: weakness,
pallor, headaches,
reduced work
productivity, inability to
concentrate, impaired
cognitive function
(children), lowered cold
tolerance
Iron overload:
infections, liver injury,
possible increased risk
of heart attack,
acidosis, bloody stools,
shock
Red meats, fish,
poultry, shellfish, eggs,
legumes, dried fruits
Zinc
Part of the hormone
insulin and many
enzymes; involved in
making genetic material
and proteins, immune
reactions, transport of
vitamin A, taste
perception, wound
healing, the making of
sperm, and normal fetal
development.
Growth failure in
children, sexual
retardation, loss of
taste, poor wound
healing, eye lesions
leading to impaired
dark adaptation
Fever, nausea,
vomiting, diarrhea,
muscle incoordination,
dizziness, anemia,
accelerated
atherosclerosis, kidney
failure
Protein-containing
foods: meats, fish,
shellfish, poultry,
grains, vegetables
Selenium
Assists a group of
enzymes that break
down reactive
chemicals that harm
cells.
Predisposition to heart
disease characterized
by cardiac tissue
becoming fibrous
(uncommon)
Nausea, abdominal
pain, nail and hair
changes, nerve
damage
Seafoods, organ meats,
other meats, whole
grains and vegetables
depending on soil
content
Iodine
A component of two
thyroid hormones,
which help to regulate
growth, development,
and metabolic rate.
Goiter, cretinism
Depressed thyroid
activity; goiter-like
thyroid enlargement
Iodized salt; seafood;
bread; plants grown in
most parts of the
country and animals fed
those plants.
Copper
Necessary for the
absorption and use of
iron in the formation of
hemoglobin; part of
several enzymes.
Anemia, bone
abnormalities (rare in
human beings)
Vomiting, diarrhea, liver
damage
Organ meats, seafood,
nuts, seeds, whole
grains, drinking water
Manganese
Facilitator, with
enzymes, of many cell
processes.
(In experimental
animals): poor growth,
nervous system
disorders, reproductive
abnormalities
Nervous system
disorders
Widely distributed in
foods
Fluoride
An element involved in
the formation of bones
and teeth; helps to
make teeth resistant to
decay.
Susceptibility to tooth
decay
Fluorosis (discoloration
of teeth), nausea,
diarrhea, chest pain,
itching, vomiting
Drinking water (if
fluoride containing or
fluoridated), tea,
seafood
Chromium
Associated with insulin
and required for the
release of energy from
glucose.
Diabetes-like condition
marked by an inability
to use glucose normally
None reported
Meat, unrefined foods