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Chapter 13
Trace Minerals
Key Terms
1.
fluorosis: Mottled discoloration and pitting of tooth enamel caused by prolonged
ingestion of excessive fluoride.
2.
albumin: A protein that circulates in the blood and helps transport many minerals and
some drugs.
3.
transferrin: A protein synthesized in the liver that transports iron in the blood to the red
blood cells for use in heme synthesis.
4.
ceruloplasmin: A copper-dependent enzyme that enables iron to bind to transferrin. Also
known as ferroxidase I.
5.
hemosiderin: An insoluble form of storage iron.
6.
ferritin: A major storage form of iron.
7.
geophagia: Ingestion of clay or dirt.
8.
Menkes’ syndrome: A genetic disorder that results in copper deficiency.
9.
hypogonadism: Decreased functional activity of the gonads (ovaries or testes) with
retardation of growth and sexual development.
10.
heme iron: The iron found in the hemoglobin and myoglobin of animal foods.
Fill-in-the-Blank
1.
Wilson’s disease is a genetic disorder of increased copper absorption, which leads to
toxic levels in the liver and heart.
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2.
A hereditary disorder in which excessive absorption of iron results in abnormal iron
deposits in the liver and other tissues is hemochromatosis.
3.
Cretinism is a congenital condition often caused by severe iodine deficiency during
gestation; it is characterized by arrested physical and mental development.
4.
Keshan disease is a selenium-deficiency disease that impairs the structure and function
of the heart.
5.
A goiter is a chronic enlargement of the thyroid gland, visible as a swelling at the front of
the neck; it is usually associated with iodine deficiency.
6.
Hypothyroidism is the result of a lowered level of circulating thyroid hormone, with
slowing of mental and physical functions.
7.
Compounds that interfere with iodine absorption and can induce goiter are called
goitrogens.
8.
The term galvanized describes iron or steel with a thin layer of zinc plated onto it to
protect against corrosion.
9.
A chemical complex with a central iron atom that forms the oxygen-binding part of
hemoglobin and myoglobin is heme.
10.
The oxygen-transporting protein of muscle that resembles blood hemoglobin in function
is myoglobin.
11.
The thyroid-stimulating hormone (TSH) is a hormone secreted from the pituitary gland
at the base of the brain that regulates synthesis of thyroid hormones.
12.
The iron in plants and animal foods that is not part of hemoglobin or myoglobin is called
non-heme iron.
13.
Toxicity from excess iron is called iron overload.
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Fill-in-the-Blank Summary
Minerals
Minerals are essential organic elements. Absorption of them is limited by several factors,
among them physiological need and the presence of competing minerals. Unlike
vitamins, minerals are not destroyed by heat, light, and acidity. Like vitamins, however,
minerals are micronutrients. They are needed in relatively small amounts. Minerals are
often grouped as major minerals and trace minerals. Compared with major minerals, the
total amount of trace minerals in your body is small. Foods from both plants and animals
are sources of minerals. Generally speaking, however, animals are more reliable mineral
sources. There are seven major minerals. Two disorders in which major minerals play
critical parts are hypertension and osteoporosis, which primarily affects postmenopausal
women.
Short Answer
1.
What is a primary function of selenium?
Selenium is best known for its role as an essential component of the antioxidant enzymes
glutathione peroxidases. Selenium interacts with vitamin E in antioxidant systems and with
iodine in thyroid hormone metabolism. It is also important for good immune function.
2.
Why is a copper mixing bowl the best choice for mixing meringue?
Making meringues in a copper bowl leads to a creamier, yellowish foam that is harder to
overbeat into a lumpy liquid. The copper bowl contributes copper ions to conalbumin, a
metal-binding egg protein, thus stabilizing the whipped egg whites.
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3.
Which type of food provides the most absorbable iron?
Red meat
4.
Iron is a key component in transporting oxygen. Identify the two heme proteins which
iron is a component of, and list one other role of iron in the body.
Iron is a key component of the oxygen transporters hemoglobin and myoglobin. Iron is also
a component of many enzymes involved in energy metabolism.
5.
Phytate can bind zinc in insoluble complexes. Identify foods which contain phytates and
therefore decrease zinc absorption.
Phytate, which is present in plant products such as cereals and legumes, can bind zinc in
insoluble complexes, thus inhibiting zinc’s absorption.
6.
Which mineral has the following characteristics: is a component of ceruloplasmin, the
enzyme that catalyzes the oxidation of iron for transport in transferrin; food sources of
this mineral include organ meats, nuts and seeds, legumes, peanut butter, chocolate, and
dried fruits.
Copper
7.
This mineral is unique in that the main dietary source is water, not food.
Fluoride
Labeling
There are several factors that affect the availability of minerals. Identify these factors in the
following image.
Polyphenols; Oxalate; Other minerals competing for absorption; Acidity of intestinal
environment; Person’s need; Fiber; Phytate
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