Lec. 6
Introduction
 Minerals constitute about 4% of body weight. The major
mineral content of the skeleton consists of calcium and
phosphorus in a ratio of approximately 2:1. Any change
of one may be reflected in changes of the other.
 Minerals are present in the body in a diverse array of
organic compounds such as phosphoproteins,
phospholipids, hemoglobin, and thyroxine; in inorganic
compounds such as sodium chloride, potassium
chloride, calcium, and phosphate; and as free ions.
 Different body tissues contain different quantities of
different elements. For example, bone has a high
content of calcium, phosphorus, and magnesium;
soft tissue has a higher quantity of potassium.
 Minerals function as constituents of enzymes,
hormones, and vitamins. They are involved in
regulating cell membrane permeability, osmotic
pressure, and acid-base and water balance.
 Unlike vitamins, minerals exist in plants in varying
amounts, according to the composition of the soil in
which the plant is grown.
 Mineral intake varies considerably from region to
region, although the use of foods delivered from diverse
geographic locations tends to minimize intake
variations.
 Mineral deficiency is often difficult to evaluate.
Trace Elements
 Trace elements, which are present in minute
quantities in plant and animal tissue, are
considered essential for numerous physiologic
processes.
 "Ultratrace minerals" have been defined as those
elements with an estimated dietary requirement of
usually less than 1 mcg/g.
1. Chromium
Description
 About 5 mg of chromium is present in the normal
adult, and levels decline with age.
 Higher concentrations occur in the hair, spleen,
kidney, and testes, and lesser concentrations are
present in the heart, pancreas, lungs, and brain.
 Chromium functions to maintain normal glucose
use.
 Fatty acid stimulation and cholesterol synthesis are
attributed to chromium.
 Significant amounts of chromium are present in
liver, fish, whole grains, and milk.
Indications
 Deficiency of trivalent chromium, the chemical form
1.
2.
3.
4.
5.
6.
present in diets, is manifested by:
Glucose intolerance,
Elevated circulating insulin,
Glycosuria,
Fasting hyperglycemia,
Elevated serum cholesterol and triglycerides,
Neuropathy, and encephalopathy.
7. Impaired
glucose tolerance may be a
manifestation
of
chromium
deficiency,
especially in older persons and protein-calorie
malnourished infants.
8. Low
chromium concentrations have been
associated with juvenile diabetes and coronary
artery disease.
Dose/RDA
 The estimated safe and adequate dietary intake for
adults has been set at 50-200 mcg per day.
Chromium has a relatively high margin of safety.
Chromium is available in 1-mg tablets.
Adverse Effects/Drug Interactions
 The oral administration of trivalent chromium has
not been reported to be toxic.
2. Iodine
Description
 The thyroid gland contains about one-third of the iodine
in the body, stored in the form of a complex glycoprotein,
thyroglobulin.
 The only known function of thyroglobulin is to provide
thyroxine and triiodothyronine. These hormones regulate
the metabolic rate of cells and therefore influence
physical and mental growth, nervous and muscle tissue
function, circulatory activity, and the use of nutrients.
 Iodine is required to synthesize thyroxine and
triiodothyronine and is an essential micronutrient.
Although in high concentrations iodine inhibits the
release of these hormones, in its absence thyroid
hypertrophy occurs, resulting in classic goiter.
 The consumption of foods from diverse sources
and the addition of iodide to table salt have
essentially eliminated goiter.
 The primary dietary source of iodine is iodized salt,
which contains 1 part of sodium or potassium iodide
per 10,000 parts (0.01%) of salt.
 A dose of about 95 mcg of iodine can be obtained from
about one-fourth of a teaspoon of salt (1.25 g).
 Additional dietary sources of iodine include saltwater
fish and shellfish. Seacoast soils used for raising
vegetables produce vegetables with higher iodide
content because plants extract iodine from the soil.
Dose/RDA
 The RDA value of iodine is 0.15 mg for adults.
Potassium iodide is available as a tablet and
solution and is included in various combination
products.
Adverse Effects/Drug Interactions
 Symptoms of chronic iodide intoxication (iodism)
include an unpleasant taste and burning in the
mouth or throat along with soreness of the teeth or
gums. Increased salivation, sneezing, irritation of
the eyes, and swelling of the eyelids commonly
occur.
3. Iron
Description
 Iron plays an important role in oxygen and electron
transport. In the body, it is either functional or
stored.
 Functional iron is found in hemoglobin, myoglobin,
heme-containing enzymes, and transferrin, the
transport form of iron. The hemoglobin of red blood
cells represents the major body store of iron,
containing 60-70% of total body iron. The rest is
stored primarily in the form of ferritin and
hemosiderin; storage sites are the intestinal mucosa,
 Normally, adult men have iron stores of about 50
mg/kg of body weight; women have about 35 mg/kg
of body weight. The normal hemoglobin level in
adult men is about 14-17 g/100 mL of blood; in
adult women it is 12-14 g/100 mL of blood.
 Dietary iron is available in two forms. Heme iron is
found in meats and is reasonably well absorbed.
Nonheme iron constitutes most of the dietary iron
and is poorly absorbed.
 About half of the iron in meats is heme iron, which
is about 25% absorbed. The amount of absorbable
nonheme iron contributed by vegetables and grains
in the diet varies greatly.
 Iron is lost from the body (1) by the sloughing of
skin cells and GI mucosal cells; (2) by
hemorrhagic loss; (3) by menstruation; and (4)
by excretion of urine, sweat, and feces.
Indications
 Symptoms of iron deficiency are, easy fatigability,
weakness, and lassitude. Other symptoms of
anemia include pallor, split or "spoon-shaped"
nails, sore tongue, angular stomatitis, dyspnea on
exertion, palpitation, and a feeling of exhaustion.
Coldness and numbness of extremities may also be
reported. Small red blood cells and low
hemoglobin concentrations characterize iron
deficiency.
 Iron deficiency results from inadequate diet,
malabsorption, pregnancy and lactation, or blood loss.
 The four life periods during which iron deficiency is
most common are:
1) From 6 months to 4 years of age, because of the low
iron content in cow's milk;
2) During early adolescence, when rapid growth entails an
expanding red cell mass and the need for iron in
myoglobin;
3) During the female reproductive years, owing to
menstrual iron losses;
4) During pregnancy, owing to the expanding blood
volume of the mother, the demands of the fetus and
placenta, and blood losses during childbirth.
 The donation of 500 mL of blood produces a loss
of approximately 250 mg of iron. This is not a
significant problem in healthy, well-nourished
adults with adequate iron stores.
Dose/RDA
 The RDA for iron is 10 mg for adult men, 15
mg for adult women, and 30 mg for pregnant
women.
 Most healthy individuals who self-medicate,
including menstruating females, will absorb
adequate iron from one 325-mg ferrous sulfate
tablet per day. In a 325-mg ferrous sulfate tablet,
20% (about 60 mg) is elemental iron. In patients
with iron deficiencies, 20% of the elemental iron
(12 mg) may be absorbed.
Adverse Effects/Drug Interactions
 All iron products tend to irritate the GI mucosa and may
produce nausea, abdominal pain, and diarrhea.
 These adverse effects may be minimized by reducing the
dose or by giving iron with meals.
 However, because food may decrease the amount of iron
absorbed by as much as 50%, pharmacists may
recommend iron with instructions for between-meal
dosing.
4. Selenium
Description
 Selenium is present in all tissues.
 Selenium is generally incorporated into organic
compounds involving amino acids such as
methionine or cysteine. Selenium compounds are
about 80% absorbed.
 The highest concentrations are found in the
kidneys and liver; the lowest are in the lungs and
brain. The kidney is the primary route of excretion.
 Dietary
sources of selenium include meat,
seafoods, and some cereal grains. Vegetables and
fruits contain little of this element.
 The selenium content of foods depends on the soils
in which the plants are grown.
Indications
 Selenium is an essential trace element in humans,
but deficiencies are not common in the general
population.
 Selenium deficiency has been reported in patients
with alcoholic cirrhosis, probably owing to an
insufficient diet or the altered metabolism of
selenium.
 Epidemiologic studies suggest that cancer and
heart disease may be common in areas of low
selenium availability.
Dose/RDA
 The RDA for selenium has been set at 70 mcg for
adult men and 50-55 mcg for adult women.
Selenium is included in some multivitamin and
mineral preparations. It is available as 50-mcg
tablets and in various strengths in combination
products.
Adverse Effects/Drug Interactions
 Toxic effects reported include loss of hair and
nails, skin lesions, and CNS and teeth involvement.
 Selenium toxicity may be evidenced by growth
retardation, muscular weakness, infertility, focal
hepatic
necrosis,
respiratory failure.
bronchopneumonia,
and
5. Zinc
Description
 Zinc is an integral part of at least 70 metalloenzymes,
including carbonic anhydrase, lactic dehydrogenase,
alkaline phosphatase, carboxypeptidase, aminopeptidase,
and alcohol dehydrogenase.
 It is also a cofactor in the synthesis of DNA and RNA, and
it is involved in the mobilization of vitamin A from the
liver and in the enhancement of follicle-stimulating
hormone and luteinizing hormone.
 It is essential for normal cellular immune functions
and for spermatogenesis and normal testicular
function, and it is important in the stabilization of
membrane structure.
 Most dietary zinc (about 70%) is derived from
animal products. Good sources of zinc include liver;
high-protein foods such as beef, lamb, legumes, and
peanuts; and whole-grain cereals.
Indications
 Symptoms
of zinc deficiency include growth
retardation, loss of appetite, skin changes, and
immunologic abnormalities.
 Additional symptoms of deficiency may include delayed
sexual maturation, hypogonadism and hypospermia,
alopecia, behavioral disturbances, night blindness,
impaired taste and smell, and impaired wound healing.
 Malabsorption syndromes, infection, myocardial
infarction, major surgery, alcoholism, liver
cirrhosis, high-fiber diets rich in phytate,
pregnancy, and lactation predispose an individual
to a suboptimal zinc status.
 Iron supplements decrease zinc absorption just as
zinc supplements decrease iron absorption,
probably owing to competition for the same
transport system.
Dose/RDA
 The RDA for zinc is 15 mg and 12 mg for adult
men and women, respectively.
 The RDA for infants is 5 mg and for children, 10
mg.
 Because zinc is only 10-40% absorbed from the
GI tract, ingestion of 220-mg dose form of zinc
sulfate (50 mg of elemental zinc) will supply 5-20
mg of zinc.
 Zinc is available in various salt forms as capsules,
generally ranging in strength from 1.5 to 50 mg of
elemental zinc, and in numerous combination
products in various strengths.
Adverse Effects/Drug Interactions
 The ingestion of 2 g or more of zinc sulfate has
resulted in GI irritation and vomiting.
 Copper levels may be adversely affected by high
intake of zinc, and zinc may decrease tetracycline
absorption.
 Because zinc may cause GI upset, it can be taken
with food.