|
Symptoms Associated with Copper Deficiency
- White hair
- Gray hair
- Dry brittle hair ("steely wool" in sheep)
- Ptosis (sagging tissue - eye lids, skin etc.)
- Hernias (Congenital and acquired)
- Varicose veins
- Aneurysms (large artery blowouts, cerebral artery blowouts)
- Kawasaki Disease (congenital aneurysms with Streptococcal
infection)
- Anemia (especially in vegan and high milk diets)
- Hypo and hyper thyroid
- Arthritis (especially where growth plate is involved)
- Ruptured vertebral disc
- Liver cirrhosis
- Violent behavior, blind rage, explosive outbursts, criminal
behavior
- Learning disabilities
- Cerebral palsy and hypoplasia of the cerebellum (congenital
ataxia)
- High blood cholesterol
- Iron storage disease (abnormal iron accumulation in liver)
- Reduced glucose tolerance (low blood sugar)
- Neutropenia (low neutrophils)
Copper is essential to all living organisms and is a universally
important cofactor for many hundreds of metalloenzynes. Copper
deficiency is widespread and appears in many forms . Copper is
required in many physiological functions (RNA, DNA, lysil oxidase
cofactor, melanin production (hair and skin pigment), electron
transfer of oxygen subcellular respiration, tensile strength of
elastic fibers in blood vessels, skin, vertebral discs, etc.).
Neonatal enzootic ataxia (sway back, lamkruis) was recognized as
a clinical entity in 1937 as a copper deficiency in pregnant sheep.
Copper supplements prevented the syndrome which was characterized by
demyelination of the cerebellum and spinal cord. Cavitation or
gelatinous lesions of the cerebral white matter, chromatolysis,
nerve cell death and myelin aplasia (failure to form). These are all
changes identical with human cerebral palsy.
Four to six of every 100 Americans autopsied have died of a
ruptured aneurysm, an additional 40 percent have aneurysms that had
not yet ruptured.
The average well-nourished adult human body contains between 80
and 120 mg of copper. Concentrations are higher in the
brain, liver, heart and kidneys. Bone and muscle have lower
percentages of copper but contain 50 percent of the body total
copper reserves because of their mass. It is of interest that the
greatest concentration of copper is found in the newborn and their
daily requirement is 0.08 mg/kg, toddlers require 0.04 mg/kg and
adults only 0.03 mg/ kg.
The average plasma copper for women ranges from 87 to 153 mg/dl
and for men it ranges from 89 to 137 mg/dl; about 90 percent of the
plasma copper is found in ceruloplasmin.
Copper functions as a co-factor and activator of numerous
cuproenzymes that are involved in the development (deficiency of Cu
in the pregnant female results in congenital defects of the heart, i.
e. - Kawasaki Disease and brain cerebral palsy and hypoplasia of the
cerebellum) and maintenance of the cardiovascular system (deficiency
results in reduced lysyl oxidase activity causing a reduction in
conversion of pro elastin to elastin causing a decrease in tinsel
strength of arterial walls and ruptured aneurysms and skeletal
integrity (deficiency results in a specific type of arthritis of the
young in the form of spurs in the bones growth plate); deficiency
can result in myelin defects; deficiency results in anemia; and poor
hair keratinization and loss of hair color. Neutropenia (reduced
numbers of neutophillic WBC) and leukopenia (reduced total WBC) are
the earliest indicators of copper deficiency in infants; infants
whose diets are primarily cows milk frequently develop anemia; iron
storage disease can result from chronic copper deficiency.
Menkes' Kinky Hair Syndrome is thought to be a sex-linked
recessive defect of copper absorption. The affected infants exhibit
retarded growth, defective keratin formation and loss of hair
pigment, low body temperature, degeneration and fracture of aortic
elastin (aneurysms), arthritis in the growth plate of long bones,
and a progressive mental deterioration (brain tissue is totally free
of the essential enzyme Cytochrome c oxidase). Because of absorption
problems of metallic copper, injections of copper are useful.
Serum and plasma copper increase 100 % in pregnant women and
women using oral contraceptives. Serum copper levels are also
elevated during acute infections, liver disease and pellagra (niacin
deficiency).
Accumulations of copper in the cornea form - Kayser Fleischer
rings.
Copper deficiency and thyroid function
Rats were fed diets containing adequate, marginal or deficient
amounts of copper for 35 days. Copper deficiency resulted in a
significant increase in serum cholesterol levels and a significant
decline in plasma thyroxine concentrations and body temperatures.
Compared with rats fed the adequate diet, those fed the marginal and
deficient diets had significantly lower plasma concentrations of
triiodothyronine (T3) and significantly higher TSH levels. The
activity of thyroxine 5'-monodeiodinase (the enzyme that converts T4
to T3) was reduced in the liver and brown adipose tissue of copper
deficient rats.
COMMENT: This study suggests that copper deficiency
interferes with thyroid hormone metabolism and can promote
hypothyroidism, as indicated by a reduction in T3 levels and body
temperatures and an increase in TSH. Copper, zinc and selenium all
have been shown to play a role in the metabolism of thyroid
hormones, and a deficiency of any one of these trace minerals might
be a contributing factor in patients who exhibit hypothyrold
symptoms.
Dr. Carl Pfeiffer has pointed out that an excessive body burden
of copper can result in various neuropsychiatric symptoms. Because
of Pfeiffer's work, many clinicians view copper primarily as a toxic
mineral (because copper supplements are not as water-soluble as they
should be). Indeed, a number of popular multivitamin/mineral
formulas are advertised as being "copper free." However, copper is
also an essential nutrient, and the average American diet provides
only about half the RDA (about 1 mg/day). Therefore, mild copper
deficiency may be a more common problem than copper excess.
Lukaski H C et al. Body temperature and thyroid hormone
metabolism of copper deficient rats. Nutr Biochem
1995;6:445-451.
Copper is an essential trace mineral. The body of an adult
contains 100 mg to 150 mg of copper. Though copper is present in all
tissues, including red cells, the liver is the main site of copper
storage. Most of serum copper is bound to ceruloplasmin, the copper
transport protein synthesized by the liver. Ceruloplasmin also aids
in iron transportation and storage. Like most trace minerals, copper
functions as an enzyme cofactor by activating certain key enzymes
required to strengthen the structural protein collagen, which in
turn strengthens cartilage, tendons, bones, and blood vessels.
Copper also serves as a cofactor of a protein in the blood that
helps maintain lung tissue and prevent emphysema; and it is
essential for insulating (mylination) nerve cells. As a cofactor for
the enzyme superoxide dismutase, copper helps prevent oxidative
damage by a highly reactive form of oxygen and thus is classified as
an antioxidant. Copper functions as a cofactor for cytochrome
oxidase of mitochondria, the enzyme complex that ultimately
transfers electrons from the oxidation of fat, carbohydrate and
protein to oxygen for energy production. Copper also serves as a
cofactor in the synthesis of norepinephrine, an important
neurotransmitter and adrenal hormone.
The estimated safe and adequate daily intake of copper for normal
adults is 2 to 3 mg. About 30% of dietary copper is assimilated.
Good sources of copper include liver, kidneys, shellfish, nuts,
seeds, fruit and dried legumes. Cow's milk is low in copper. The
standard American diet is copper deficient and between 66 and 75% of
the U.S. population do not consume enough copper. Dieters, elderly
persons and chronic alcoholics are especially vulnerable. The
following factors increase the need for copper: excessive dietary
fiber, high zinc supplements (50 mg or more daily), cadmium,
excessive vitamin C and excessive sugar (fructose) intake (at least
in rats).
Low copper consumption increases the risk of high blood
cholesterol and coronary heart disease, lowered immunity, gout,
diabetes, high blood pressure, anemia, nervous disorders, decreased
pigmentation of skin, fragile bones and erratic heartbeat. Low
dietary copper is linked with an increased risk of heart attack.
Evidence also links copper deficiency with increased oxidative
damage to cell membranes. Levels of norepinephrine in the brain are
decreased with copper deficiency but may be restored by supplemental
copper. There are certain precautions to keep in mind for copper
supplements. Consumption of 10 to 15 mg of copper daily can cause
side effects. Patients with a rare copper accumulation disease
(Wilson's disease) should not use copper supplements. An excessive
copper overload has been linked to various psychiatric syndromes. A
green stain in the sink from a faucet drip, or in a teakettle,
suggests excessive copper in drinking water, leached from copper
plumbing.
Prohaska, Joseph R. and Failla, Mark L., "Copper and Immunity,"
in Human Nutrition--A Comprehensive Treatise, vol. 8 of
Nutrition and Immunology, Klurfeld, David M., ed. New York:
Plenum Press, 1993.
Also, included from: Minerals in Animal and Human
Nutrition
By Lee Russell McDowell
Copper Physiology
Copper is required for cellular respiration, bone formation,
proper cardiac function, connective tissue development, myelination
of the spinal cord, keratinization, and tissue pigmentation. Copper
is an essential component of several physiologically important
metalloenzymes including cytochrome oxidase, lysyl oxidase,
superoxide dismutase, dopamine-beta-hydroxylase, and
tyrosinase.
1. IRON METABOLISM AND CELLULAR RESPIRATION
Along with Fe, Cu is necessary for hemoglobin synthesis. Copper
is not contained in hemoglobin, but a trace of it is necessary to
serve as a catalyst before the body can utilize Fe for hemoglobin
formation. Anemia can develop with either a Fe or Cu deficiency.
With Cu deficiency there is an apparent delay in maturation and
shortened life span of red blood cells (Baxter and Van Wyk, 1953).
Copper plays a key role in Fe absorption and mobilization. Serum
Fe levels tend to be low in Cu deficiency, and hypochromic anemia
develops while intestinal mucosa and liver Fe levels are higher than
normal. Ceruloplasmin (ferroxidase), which is synthesized in the
liver and contains Cu, is necessary for the oxidation of Fe,
permitting it to bind with the Fe-transport protein, transferrin.
Ceruloplasmin (Evans, 1978) is a multifunctional enzyme involved in
Fe metabolism, transport of Cu, and regulation of certain amines.
Iron must be converted to the ferrous form to be mobilized from
stored ferritin and/or to be incorporated into hemoglobin or
myoglobin. For storage as ferritin or for transport as transferrin,
Fe must be converted to the ferric form (Curzon, 1961), a reaction
performed by ceruloplasmin.
Copper is a constituent of the important metalloenzyme,
cytochrome oxidase. This enzyme is the terminal oxidase in the
respiratory chain; it catalyzes the reduction of 0, to water, an
essential step in cellular respiration.
2. CROSS-LINKING OF CONNECTIVE TISSUE
With a Cu deficiency, there is failure of collagen to undergo
cross-linking and maturation (Harris and O'Dell, 1974). The key
Cu-containing enzyme in the formation of the cross-links in collagen
and elastin is lysyl oxidase, which is necessary to add a hydroxyl
group to lysine residues in collagen, allowing crosslinking between
collagen fibers. These cross-links give the proteins structural
rigidity and elasticity. Aortic aneurysms and ruptures result from
failure to convert lysine to desmosine, the cross-linking residue in
elastin.
3. PIGMENTATION AND KERATINIZATION OF HAIR AND WOOL
Achromotrichia (lack of pigmentation) is a principal
manifestation of Cu deficiency in many species. It is commonly
observed in the hair and wool of mammals, and is usually attributed
to lack of tyrosinase (polyphenyl oxidase) activity. A breakdown in
the conversion of tyrosine to melanin is the probable explanation.
Impaired keratinization of hair and wool are noted in
Cu.-deficient animals. The characteristic physical properties of
wool, including crimp, are dependent on disulfide groups that
provide cross-linkages or bonding of keratin and on alignment or
orientation of long-chain keratin fibrillae in the fiber. Straight
steely wool has more sulfhydryl groups and fewer disulfide groups
than normal (Marston, 1946). Copper is required for formation or
incorporation of disulfide groups in keratin synthesis.
4. CENTRAL NERVOUS SYSTEM
The link between Cu deficiency and the integrity of the central
nervous system, i.e., swayback (enzootic ataxia) of lambs, results
from a reduction in cytochrome oxidase activity and thus incomplete
myelin formation (Howell and Davidson, 1959). Myelin is composed
largely of phospholipid. Loss of cytochrome oxidase in Cu deficiency
leads to depressed phospholipid synthesis by liver mitochondria. The
inhibition of myelin synthesis results in the ensuing neurological
disturbances. Other central nervous system effects of Cu deficiency
are reduction of at least two neurotransmitters, dopamine and
norepinephrine (O'Dell, 1984).
5. REPRODUCTION
Reproductive failure is commonly observed in mammals fed
Cu-deficient diets (Underwood, 1977). For rats and guinea pigs, Cu
deficiency has resulted in fetal death and resorption. Embryos from
Cu-deficient hens exhibited anemia, retarded development, and a high
incidence of hemorrhage after 72 to 96 hours of incubation, and a
reduction in monoamine oxidase activity. The anemia, hemorrhages,
and mortality are probably caused by defects in red blood cell and
connective tissue formation during early embryonic development.
6. IMMUNE SYSTEM
Copper metabolism affects T and B cells, neutrophils, and
macrophages. An impaired humoral immune response (i.e., decreased
numbers of antibody-producing cells) was observed in mice with
hypocuprosis (Prohaska et al., 1983). The magnitude of this
impairment was highly correlated with the degree of its functional
deficiency. In a literature review, Miller et al (1979)
concluded that the relationship of Cu to the immune system is
through superoxide dismutase, a Zn-, Cu-, and Mn-dependent enzyme,
and its role in the microbial systems of phagocytes.
In cattle affected by Cu deficiency induced by Mo, neutrophils
were impaired in their ability to kill ingested Candida albicans
(Boyne and Arthur, 1986). The ability of polymorphonuclear
leukocytes to phagocytose C. albicans in sheep with low Cu
status is comparatively lower than that of sheep on a normal Cu diet
(Olkowski et al 1990). A decreased resistance to infection
has been observed in sheep affected by Cu deficiency (Wooliams et
A, 1986).
7. LIPID MATABOLISM
A number of studies have demonstrated the effect of Cu deficiency
on lipid metabolism. Petering et al (1977) reported that Cu
deficiency results in elevated levels of serum triglyceride,
phospholipids, and cholesterol in the rat. Altered heart function of
rats fed low Cu is associated with alterations in lipid and
long-chain fatty acid metabolism (Cunnane et al., 1987), which may
be attributable to the predominant role of Cu in the superoxide
dismutase enzyme system.ool r Physiology
COPPER: The Missing Link in Your Diet
By Sherry A. Rogers, M.D.
When we think of copper, we often think of toxic or high levels
from copper tubing and water pipes. In reality, the majority of
Americans are deficient in copper. The National Institutes of Health
did a study showing that 81 percent of people have less than
two-thirds of the recommended daily allowance of copper. Another
study revealed that hospital meals provide only 0.76 mg of copper
per day, whereas people need 2-4 mg for health, and even more for
healing.
A study by the Food and Drug Administration showed that, in an
analysis, 234 foods that constitute the core of the American diet
provided less than 80 percent of the RDA of copper. A study of 270
United States Navy SEAL trainees, all of them highly selected
healthy young men, revealed that 37 percent had low plasma copper
levels, and plasma copper, as you will see, is a very insensitive
indicator of copper status.
One study showed that 80 percent of Americans get 1 mg of copper
per day, and another study, which analyzed 20 different types of
U.S. diets, showed that only 25 percent of the people got 2 mg of
copper a day and the majority of the diets provided 0.78 mg of
copper per day.
So all copper studies seem to point to the majority of people
being deficient.
When we studied 228 of our patients, 165 (or 72 percent) were
deficient in copper. So, no matter whose studies you look at over
the last 20 years, there is a wealth of data showing that copper
deficiency is rampant in the United States. But the best test for
copper deficiency is intracellular, or red blood cell (RBC), while
serum or plasma copper tests are too insensitive, and hence not
worth obtaining.
Why Copper Is Needed
So why do we need copper? Copper is present in about 21
different enzymes, and its importance has been known since 1928. For
example, one important enzyme is histaminase, which breaks down
histamine. So all allergic people, who overproduce histamine,
certainly need to ensure that they have normal copper levels.
Another copper-dependent enzyme is cytochrome oxidase, which is
necessary for energy metabolism. Indeed, some people with weakness
and chronic fatigue have marked copper deficiencies.
Copper is also present in superoxide dismutase, an enzyme which
is useful in protecting us from developing chemical sensitivity. For
example, a 33-year-old lab technician for years could not tolerate
shopping malls, auto exhaust fumes and many businesses because of
chemical sensitivity. She felt confused, suffered from headaches,
and became weak and tired when she breathed the higher levels of
chemicals commonly encountered in these environments. When we found
that she had a copper deficiency and corrected it, within one month
she was no longer as chemically sensitive, and could tolerate these
exposures without symptoms.
Remember that chemical sensitivity requires multiple factors, one
of which is that the person must be deficient in certain nutrients
that are necessary for the detoxification pathways to operate
normally. Once the deficiencies in these pathways are corrected many
times, the chemical sensitivity is corrected.
As well, the enzyme superoxide dismutase (SOD) plays a role in
the retarding of aging, arthritis and general body deterioration.
In fact, in nearly all diseases, lower than normal levels of SOD
are found. For example, people with colitis were found to have
much lower levels of superoxide dismutase in the bowel, and people
with Alzheimer's disease were found to have much lower levels of
superoxide dismutase in the brain. In other studies, chemically
induced tumors were analyzed and found to be low in
copper-containing protective superoxide dismutase.
Detoxification
There are many other enzyme pathways where copper is used for
the detoxification of chemicals besides superoxide dismutase. For
example, it is in polyphenol oxidase, which is necessary for the
breakdown of phenols that emit gas from common household cleaning
products. Also copper is necessary for the action of glutathione
peroxidase and catalase pathways, even though it is not directly
used in those enzymes. Studies on rats show that those which were
deficient in copper developed severe liver necroses (tissue death)
when exposed to carbon tetrachloride. But when the copper deficiency
was corrected, they did not develop the expected chemical toxicity
and suffer death.
Just as important, copper has a very important role in mood
chemistry. For example, the enzyme dopamine beta-hydroxyl is
responsible for the metabolism of norepinephrine, which affects
depression and fatigue. It is also important in the synthesis of
other mood hormones, like dopamine and serotonin (the one that many
antidepressants -like Prozac -work on), and in the major stress
(adrenal) hormone, epinephrine. And copper has an even' greater
influence on our moods, for it is necessary for the action of
aminoxidases, which influence the metabolism of many
neurotransmitter proteins in the brain that are responsible for
moods and thoughts.
The Heart Protector
With all of these benefits, copper is still essential for
many more enzymes. It is very important in protecting against
arteriolosclerosis and hypercholesterolemia; aneurysms (weakened
blood vessels that burst and can cause sudden death); EKG
abnormalities; hypercoagulable states which lead to heart attacks
and strokes; and sugar metabolism. As an example, many people with
high cholesterol lack minerals like copper to properly metabolize
their cholesterol. It is an error to prescribe cholesterol-lowering
drugs without checking the RBC copper status.
For example, copper is important in an enzyme deta-9-desaturase.
This has to do with the propermetabolism of essential fatty acids
that make up the structural integrity of cell membranes. Remember
that the most important membranes are the cell walls, from which
allergic reactions, degenerative diseases and autoimmune diseases
emanate.
Calcium channel blockers are commonly prescribed expensive drugs
to control blood pressure and heart arrhythmias, but the reason the
membrane calcium channels must be blocked has to do with minerals
and essential fatty acid deficiencies in the membranes. A
headache isn't an aspirin deficiency, so we should be less
inclined to "drug" every symptom and more inclined to find the
nutrient deficiency behind the symptom. For example, if the
mitochondrial membrane wall, where energy is created, is deficient,
we can get chronic fatigue.
Furthermore, another very important membrane is the nuclear
membrane, which protects our genetic DNA material from damage from
chemicals. When the nuclear membrane is weak, chemicals can
penetrate the nucleus and damage DNA; this is one of the mechanisms
for instigating cancers as well as other degenerative diseases.
Another Very important membrane complex is the endoplasmic
reticulum, where detoxification of everyday home, office and outdoor
chemicals must, be done.
At this point, you might be eager to run out and comer the market
on copper and consume it, but this can be dangerous without knowing
the proper level of copper, or the proper level of complementary,
but antagonistic, minerals such as (RBC) zinc, (RBC) molybdenum and
iron. By taking copper, one can lower the values of these important
minerals and create secondary deficiencies.
Foods that are high in copper include nuts, legumes (peas and
beans), seeds, organ meats and shellfish, in particular. Foods
especially low in copper are processed foods in general, especially
white flour, white sugar and fructose (fruit sugars).
Man is still trying to figure out why there are such folk
remedies as copper bracelets for the care of arthritis. Some
researchers presume that the copper is actually absorbed and
incorporated into the anti-inflammatory enzyme superoxide dismutase,
which tends to turn off inflammatory conditions like arthritis or
Lupus.
Bob, a 54-year-old engineer, had 10 years of headaches. Allergy
injections, dietary changes, and correction of nutrient deficiencies
documented on blood tests corrected other symptoms, but they did not
relieve his headaches. However, when a RBC copper deficiency was
found and corrected, within one month his headaches disappeared.
Certainly, people like this teach us that copper is the
"missing link."
About the author: Sherry A. Rogers, M.D., has a private
practice in environmental and nutritional medicine.
COPPER DEFICIENCY AND MULTIPLE SCLEROSIS
A nervous disorder in sheep characterized by uncoordination
of gait has been recognized for many years. This disorder is most
common in sheep but it has also been reported in goat kids and more
rarely in calves and piglets. Various local names have been given to
this condition but swayback is the most common. Voisin prefers the
term enzootic ataxia. In Trail, British Columbia, young dogs and
cats could not be raised without encountering similar disabilities
until more effective pollution controls were introduced in the early
1930s. More recently young foals brought into the Trail area
suffered similar problems whereas older horses survived.
These problems seemingly were all associated with a copper
deficiency in the locality or with the presence of too much lead
which element nullifies the copper present in the fodder or in the
atmosphere.
The enzootic ataxia in sheep parallels multiple sclerosis in
humans. Both diseases are characterized by demyelination, that is,
destruction of the myelin sheath.
In multiple sclerosis Plumb and Hansen found normal total copper
values both in serum and in cerebrospinal fluid but in the serum
they found reduced activity in copper oxidase. The same writers
noted "this new finding does not yet appear to have attracted
comment and its confirmation and further investigation will be
awaited with interest, since vital clues to the role of trace
minerals in myelination are badly needed."
Voisin wrote "Australian biochemists, able specialists in
deficiency diseases, set to work and found that one could prevent
the disease by administering copper salts orally to the ewes". Ruth
Allcroft obtained similar results in England.
A few years ago Dr Jean Haine, from Gloucester in England,
suggested that it might be worthwhile to add small copper
supplements in some appropriate form to those persons whose blood
contained too little copper. However this suggestion has apparently
met with no support, at least in British Columbia. This suggestion
would seem to be worth investigating.
Copper Deficiency
A variety of symptoms have been associated with copper deficiency
in animals, many of which are seen also in humans; they include
hypochromic anemia, neutropenia (low neutrophils), hypopigmentation
(graying) of the hair and skin, abnormal bone formation with
skeletal fragility and osteoporosis, vascular abnormalities and
uncrimped or steely hair. There is no single specific indicator of
copper deficiency. Measurements which, despite major limitations,
are currently considered to be of value in establishing a range for
normal copper status include serum copper (normal range 0.64-1.56 ug/ml),
ceruloplasmin (0.18-0.40mg/ml), urinary copper (32-64pg/24h) and
hair copper (10-20 ug/g), all of which are depressed in frankly
copper-deficient subjects but are less sensitive to a marginal
copper status. The possibility that a decline in erythrocyte
copper-zinc superoxide dismutase, normally 0.47 + 0.07 (SEM)
mg/g of hemoglobin, may provide a more suitable and early indication
of deficiency is being investigated.
Neutropenia is nowadays regarded as a sufficiently constant
feature of copper deficiency in humans to be of diagnostic value,
while evidence of a rapid decline in plasma enkephalins warrants
further investigation.
As late as the early to mid-1920s a new trace element, copper,
was suggested, on the basis of empirical evidence, to be of value in
the diet of rats (Bodansky, 192 1; McHargue, 1925, 1926). Copper
deficiency was subsequently shown to inhibit hematopoiesis in the
rat (Hart et al., 1928) and in exclusively milk-fed human
infants (Josephs, 1931). However, it was later discovered that
copper is required for the formation of aortic elastin (O'Dell et
al., 1961), and thus is of crucial importance for heart
functioning. Following these findings, chronic copper deficiency, or
a relative copper deficiency induced by high zinc intakes, has been
suggested to be a major etiological factor in human ischemic heart
disease (Klevay, 1975). Copper-deficient laboratory animals have
since been found to be hypercholesterolemic and hyperuricemic and to
exhibit glucose intolerance and abnormalities of cardiac function.
They also show abnormal connective tissues and lipid deposits in the
arteries. Deficient animals may die suddenly with a ruptured heart,
caused by thinning of the aortic wall. These findings have ominous
significance in the light of recent copper estimates in typical
human diets in the United States; 75% of the diets examined
furnished less than 2 mg of copper per day, the amount thought to be
required by adults (Klevay, 1982).
Tissue distribution
Copper is widely distributed in biological tissues, where it
occurs largely in the form of organic complexes, many of which are
metalloproteins and function as enzymes. Copper enzymes are involved
in a variety of metabolic reactions, such as the utilization of
oxygen during cell respiration and energy utilization. They are also
involved in the synthesis of essential compounds, such as the
complex proteins of connective tissues of the skeleton and blood
vessels, and in a range of neuroactive compounds concerned in
nervous tissue function. It has been estimated that the adult human
body contains 80 mg of copper, with a range of 50-120 mg. Tissue
copper levels range from < 1 ug/g (dry weight) in many organs to >
10 ug/g (dry weight) in the liver and brain. Copper levels in the
fetus and young infant differ from those in the adult.
Concentrations of copper may be 6-10-fold greater in the liver of
infants where, during the first 2 months of postnatal life, it
presumably serves as a store of copper to tide the infant over the
period when intake from breast milk is relatively small.
Copper in human blood is principally distributed between the
erythrocytes and the plasma. In erythrocytes, most copper (60%)
occurs as the copper-zinc metalloenzyme superoxide dismutase, the
remaining 40% being loosely bound to other proteins and amino acids.
Total erythrocyte copper in normal humans is around 0.9-1.0 ug/ml of
packed red cells.
In plasma, about 93% of copper is firmly bound to the enzyme
ceruloplasmin, believed to be involved in iron mobilization by
maintaining the supply of oxidized iron transported after its
incorporation into transferrin. The remaining plasma copper (7%) is
bound less firmly to albumin and amino acids, and constitutes
transport copper capable of reacting with receptor proteins or of
diffusing, probably in the form of charged complexes, across cell
membranes. Plasma or serum copper in normal humans is in the range
0.8-1.2 ug/ml and is not significantly influenced by cyclical
rhythms or by feeding. The mean value for females is about 10%
higher than that for males and is elevated by a factor of up to 3 in
late pregnancy and in women taking estrogen-based oral
contraceptives. |