Copper is a trace mineral that plays an important role in your metabolism, largely because it allows many critical enzymes to function properly. Although copper is the third most abundant trace mineral in the body (behind iron and zinc), the total amount of copper in your body is only 75-100 milligrams, less than the amount of copper in a penny. Copper is present in every tissue of your body, but is stored primarily in your liver, so concentrations of the mineral are highest there, with lesser amounts found in your brain, heart, kidney, and muscles.

Copper is an essential component of many enzymes. Each of the copper-containing enzymes has a distinct function, indicating that copper plays a role in a wide range of physiological processes. Copper can:

• Help your body use iron: Copper works together with iron in the formation of hemoglobin and red blood cells. Approximately 90% of the copper in your blood is incorporated into a transport protein called ceruloplasmin, which carries copper to tissues that need it. In addition, ceruloplasmin also acts as an enzyme, catalyzing the oxidation of minerals, especially iron, which enables iron to be bound to its transport protein (called transferrin) so that it can be carried to tissues that need it. Because your body needs copper to use iron, anemia may be a symptom of copper deficiency.
• Reduce tissue damage caused by free radicals: Superoxide dismutase (SOD) is a copper-dependent enzyme that catalyzes the removal of superoxide radicals from the body. Your body generates superoxide radicals during normal metabolism, as well as when white blood cells attack invading bacteria and viruses (a process called phagocytosis). If not eliminated quickly, superoxide radicals can damage cell membranes. When copper is not present in sufficient quantities, the activity of superoxide dismutase is diminished, and the damage to cell membranes caused by superoxide radicals is increased. When functioning in this enzyme, copper works together with the mineral zinc, and it is actually the ratio of copper to zinc, rather than the amount of either mineral alone, that helps the enzyme function properly.
• Maintain the health of your bones and connective tissues: Copper reduces some of the pain and swelling of rheumatoid arthritis because it is important in a number of anti-inflammatory and antioxidant enzymes. In addition, copper is a component of lysyl oxidase, an enzyme that helps synthesize collagen and elastin, the substances that provide structure, strength, and elasticity in blood vessels, bones, and joints.
• Help your body produce the pigment called melanin: Tyrosinase, a copper-containing enzyme, converts tyrosine to melanin, which is the pigment that gives hair and skin its color.
• Keep your thyroid gland functioning normally: Copper is also important for the production of the thyroid hormone called thyroxine.
• Preserve the myelin sheath that surrounds and protects your nerves: Copper is necessary for the synthesis of phospholipids for myelin sheaths that cover and protect nerves.
• Promote energy production: As a part of the enzyme cytochrome c oxidase, copper helps your mitochondria produce energy.
• Regulate mood: Dopamine is important in the regulation of your mood, and is involved in pleasure, delusions, psychosis, and drug abuse. As a part of the enzyme dopamine β-hydroxylase (DBH), copper plays a role in the conversion of dopamine to norepinephrine. When released, norepinephrine has an impact on the “fight-or-flight” response, which is your body’s biological response to stress. In addition, norepinephrine is also involved in pain, cognition, mood, emotions, movement and blood pressure.

Because copper is involved in many functions of the body, copper deficiency produces an extensive range of symptoms. These symptoms include anemia, ruptured blood vessels, osteoporosis, joint problems, brain disturbances, elevated LDL cholesterol and reduced HDL cholesterol levels, increased susceptibility to infections due to poor immune function, loss of pigment in the hair and skin, weakness, fatigue, breathing difficulties, skin sores, poor thyroid function, and irregular heart beat. Certain medical conditions including chronic diarrhea, celiac sprue, and Crohn’s disease result in decreased absorption of copper and may increase the risk of developing a copper deficiency. Unlike most minerals, copper is absorbed from the stomach, and proper levels of stomach acid are important for this absorption. People with low stomach acid (hypochlorhydria) or those who take antacids may be at increased risk of copper deficiency. Because zinc can compete with copper and interfere with its absorption, people who supplement with inappropriately high levels of zinc and lower levels of copper may increase their risk of copper deficiency. Inadequate copper status can also occur in infants fed only cow’s milk without supplemental copper.

Excessive intake of copper can cause abdominal pain and cramps, nausea, diarrhea, vomiting, and liver damage. In addition, elevated copper levels, especially when zinc levels are also low, may be a contributing factor in many medical conditions including schizophrenia, hypertension, stuttering, autism, fatigue, muscle and joint pain, headaches, childhood hyperactivity, depression, insomnia, senility, and premenstrual syndrome. Postpartum depression has also been linked to high levels of copper. This is because copper concentrations increase throughout pregnancy to approximately twice normal values, and it may take up to three months after delivery for copper concentrations to normalize. Because excess copper is excreted through bile, copper toxicity can occur in individuals with liver disease. In 2000, the Institute of Medicine at the National Academy of Sciences established the Tolerable Upper Intake Levels (ULs) for copper for people 19 years and older at 10,000 micrograms.

The leaching of copper from copper water pipes can increase the copper content of drinking water. Cooking with copper cookware can also increase the copper content of foods. Conversely, foods that require long-term cooking can have their copper content substantially reduced. The cooking of navy beans, for example, can result in the loss of half their original copper content. The processing of whole grains can also dramatically reduce copper content. White flour contains about 70% less copper than whole wheat. Many vegetables and whole grains now appear to be lower in copper than they were during the mid-1900’s, likely due to the depletion of copper from soils.

Copper reacts with a variety of other nutrients, including iron, zinc, molybdenum, sulfur, selenium, and vitamin C. However, there’s no evidence that nutrients from food interfere with the absorption of copper or its interaction with a variety of minerals after it has been absorbed into your body. Supplements, however, often provide vitamins and minerals in much higher doses than you would get from food. Zinc supplements, when taken at 50 milligrams or more on a daily basis over an extended period of time, can lower the availability of copper. There’s also some evidence that vitamin C supplements of 1,000 milligrams per day or more may also decrease copper availability. Likewise, too much iron in infant formula can lower absorption of copper from the formula.

Excellent sources of copper include sesame seeds, cashews, soybeans, sunflower seeds, barley, tempeh, chickpeas, lentils, lima beans, crimini mushrooms, pumpkin seeds, peanuts, spelt, almonds, and walnuts. Very good sources include turnip greens, olives, spinach, chard, blackstrap molasses, asparagus, buckwheat, green peas, tofu, and kale. Good sources of copper include sweet potato, pineapple, flax seeds, winter squash, mustard greens, shiitake mushrooms, tomatoes, leeks, raspberries, and beets.

Food Sources of Copper

Copper works together with iron in the formation of hemoglobin and red blood cells.

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