Copper

Although copper is the third most abundant trace mineral in the body (after iron and zinc), only about 75-100 milligrams of this important mineral are found in the body, less than that contained in a copper penny. Copper was first recognized to be a normal blood constituent in the 1870s. As an essential trace mineral, it is involved in several very important enzymatic reactions. Although primarily stored in the liver, with lesser amounts found in the brain, heart, kidneys, and muscles, copper can be found in every tissue of the body.

Physiological functions of copper

• Assists in the utilization of iron
• Reduces tissue damage caused by free radicals
• Maintains the health of bones and connective tissues
• Helps produce the pigment, melanin
• Keeps the thyroid gland functioning normally
• Preserves the myelin sheath that surrounds and protects nerves

Physiological events that may signal a need for greater copper intake

• Iron deficiency anemia
• Blood vessels that rupture easily
• Fatigue and weakness
• Elevated LDL cholesterol and reduced HDL cholesterol levels
• Bone and joint problems
• Frequent infections
• Loss of hair or skin color
• Difficulty breathing
• Irregular heart beat
• Skin sores

Functions of copper

Utilization of iron

About 90% of the copper in the blood is found in a compound known as ceruloplasmin, a transport protein that carries copper to tissues throughout the body. In addition to shuttling copper throughout the body, ceruloplasmin also functions as an enzyme that is capable of catalyzing mineral oxidation. One of the minerals that ceruloplasmin oxidizes is iron, in a reaction necessary for iron to be bound to transferrin, its own transfer protein, which carries it to the tissues where it is needed. As a result of this relationship between ceruloplasmin and iron, iron deficiency anemias may be a symptom of copper deficiency.

Elimination of free radicals

Copper plays a very important role in the bodys antioxidant defense system, notably through it role as a component of copper-dependent superoxide dismutase (SOD), a molecule that catalyzes the removal of superoxide radicals from the body. Superoxide radicals are generated not only during normal metabolism but also during phagocytosis, the process by which white blood cells attack bacteria and viruses. If superoxide radicals are not quickly neutralized or eliminated, they can cause cellular membrane damage. Without adequate supplies of copper, SOD activity is diminished and damage to cellular membranes ensues. Copper actually works together with the mineral zinc when functioning in this enzyme with the important factor related to SODs activity being the ratio of copper to zinc, rather than the absolute amount of copper or zinc alone.

Bone and connective tissue development

Copper is a component of lysyl oxidase, an enzyme that participates in collagen and elastin synthesis. As a result, copper plays an important role in both bone and connective tissue health.

Other functions of copper

Copper plays a role in energy production, blood clotting and the conversion of dopamine to norepinephrine, respectively, since it is a component of the enzymes cytochrome c oxidase, Factor IV and dopamine hydroxylase. It is also necessary for the production of the thyroid hormone thyroxine as well as the synthesis of phospholipids that are part of the myelin sheaths that surround and protect nerves. Additionally, copper is a constituent of tyrosinase, which converts tyrosine to melanin, the pigment that gives hair and skin its color.

Causes and symptoms of copper deficiency

Copper deficiency can cause a host of different symptoms, yet even given the fact that most Americans consume less than recommended amounts of copper in their diet, symptoms of copper deficiency are relatively rare. However, medical conditions such as chronic diarrhea, celiac sprue, and Crohns disease can result in decreased absorption of copper. These conditions may therefore increase the risk of developing a copper deficiency.

Additionally, hypochlorhydria, compromised stomach acid, may put a person at risk for copper deficiency. This is because, unlike many other minerals that are absorbed in the small intestine, copper is absorbed in the stomach and is dependent upon hydrochloric acid for its absorption. Regular consumption of antacids can therefore also put someone at risk for copper deficiency.

As zinc competes with copper in the small intestine, interfering with its absorption, very high levels of zinc supplementation without appropriate copper supplementation can also increase the risk of copper deficiency.

Children with low protein intake as well as infants fed only cows milk without supplemental copper have been observed to experience inadequate copper status.

Since copper is an essential component of many different enzymes, deficiency can manifest as a broad range of symptoms including: iron deficiency anemia, ruptured blood vessels, joint problems, osteoporosis, frequent colds, flu and infections, elevated LDL and reduced HDL cholesterol levels, brain disturbances, weakness, fatigue, breathing difficulties, skin sores, poor thyroid function, irregular heart beat and loss of pigment in the hair and skin. It is important to note that while these symptoms can occur, signs of copper deficiency are rare in the general U.S. population, although it can occur under special circumstances as noted above.

Causes and symptoms of copper toxicity

Since many municipalities have switched from galvanized water pipes to copper water pipes, the amount of copper found in drinking water has increased. This has caused nutritionists in recent years to become more concerned about copper toxicity than about copper deficiency.

Nausea, abdominal pain and cramps, diarrhea, vomiting and liver damage are signs of excessive copper intake. Some experts also believe that elevated copper levels concomitant with depleted zinc levels may be a contributing factor in various medical conditions including hypertension, joint and muscle pain, headaches, fatigue, childhood hyperactivity, autism, stuttering, depression, insomnia, senility, schizophrenia, and premenstrual syndrome.

Elevated copper levels have also been linked to postpartum depression since copper concentration tends to increase throughout pregnancy to approximately twice the normal values, and it usually takes up to three months after delivery for the copper levels to return to normal. Since excess copper can be excreted through the bile, toxicity is thought to be more common in individuals with liver disease or other medical conditions that manifest in compromised bile function.

Wilsons disease is a medical condition where the toxic effects of high tissue levels of copper can seen be clearly seen. Wilsons disease is a genetic disorder characterized by copper accumulation in various organs secondary to the inadequate synthesis of ceruloplasmin (a transport protein that carries copper throughout the body) by the liver. This condition primarily affects the liver, kidneys, and brain, causing degenerative physiological changes such as liver cirrhosis, muscular rigidity and spastic contractions, and emotional disturbances. These effects are fatal if left untreated. Avoiding foods rich in copper and copper-containing supplements is part of the treatment for Wilsons disease in addition to therapy with chelating agents that remove the excess copper from the body.

In 2000, the Institute of Medicine at the National Academy of Sciences established the following Tolerable Upper Intake Levels (UL) for copper:

• 0-12 months: not possible to establish a UL, sources of copper must be from food and formula only
• 1-3 years: 1000 micrograms
• 4-8 years: 1000 micrograms
• 9-13 years: 5000 micrograms
• 14-18 years: 8000 micrograms
• 19 years and older: 10,000 micrograms
• Pregnant women 14-18 years: 8000 micrograms
• Pregnant women 19 years and older: 10,000 micrograms
• Lactating women 14-18 years: 8000 micrograms
• Lactating women 19 years and older: 10,000 micrograms

The effect of cooking, storage and processing on copper

Vegetables and whole grains today tend to have lower levels of copper than they did during the mid-1900s with reduced copper levels suggested to be related to soil copper depletion.

Long-term cooking of food can substantially reduce copper content. The processing of wheat significantly reduces the grains copper content; the conversion of whole grain wheat into 60-70% extraction wheat flour, results in approximately 70% reduction in copper content. Legumes are another food whose copper content can be affected by cooking with the cooking of navy beans, for example, able to reduce copper content by 50%.

Cooking with copper cookware can increase the copper content of foods while the leaching of copper from copper water pipes can increase the copper content of drinking water.

Interactions between medications and copper

Medications that may decrease copper levels:

• AZT (Azidothymidine, Zidovudine, Retrovir)
  • may reduce blood levels of copper
• Histamine blockers such as Famotidine (Pepcid, Pepcid AD) and Nizatidine (Axid, Axid AR)
  • decreases stomach hydrochloric acid levels, a substance required by copper for proper absorption
• Antacids (i.e., Tums)
  • decreases stomach\'s secretion of hydrochloric acid, a substance required by copper for proper absorption
• Penicillamine (Cuprimine, Depen)
  • chelating agent used to reduce toxic copper deposits in people with Wilsons disease

Medications that increase the absorption of copper include:

• Birth control pills (oral contraceptives)

Medications whose anti-inflammatory effects may be enhanced by copper:

• Non-steroidal anti-inflammatory medications (NSAIDs) including etodolac (Lodine), ibuprofen, nabumetone (Relafen), naproxen, and oxaprozin

Interactions that occur between copper and other nutrients

Copper interacts with a variety of other nutrients. Copper absorption is inhibited by vitamin C, iron and manganese. Since copper and zinc compete for absorption, high supplemental doses of zinc may cause a copper deficiency. Copper may also be reduced by molybdenum and sulfur since these two minerals form complexes with copper. Copper deficiency has been shown to reduce the activity of selenium-dependent enzymes, while calcium and phosphorous increase copper excretion.

Health conditions thast require special emphasis on copper

Individuals who have the following health conditions should pay special attention to their copper status:

• Allergies
• Anemia
• Baldness
• Bedsores
• Coronary heart disease
• HIV/AIDS
• Hypothyroid disease
• Leukemia
• Osteoporosis
• Periodontal disease
• Rheumatoid arthritis
• Stomach ulcers

Forms in which copper is found in dietary supplements.

Copper is primarily found in a chelated form in dietary supplements, complexed with organic acids such as gluconic acid or picolinic acid as well as amino acids such as glycine and lysine. It can also be found in its inorganic form, such as copper sulfate. Each of these delivery forms seems to have merit with the type to use dependent upon whether there is a need for the specific organic acid or amino acids to which the copper is chelated.

Foods that are concentrated sources of copper

Excllent sources of copper include calfs liver, crimini mushrooms, spirulina and turnip greens. Very good sources include asparagus, blackstrap molasses, kale, summer squash and Swiss chard while foods that are good sources of this mineral include cashew nuts, eggplant, mustard greens, sunflower seeds and tempeh.