Copper is an essential trace mineral necessary for survival. It is found in all body tissues and plays a role in making red blood cells and maintaining nerve cells and the immune system.

It also helps the body form collagen and absorb iron, and plays a role in energy production.

Most copper in the body is found in the liver, brain, heart, kidneys, and skeletal muscle.

Both too much and too little copper can affect how the brain works. Impairments have been linked to Menkes, Wilson's, and Alzheimer's disease

Deficiency is rare, but it can lead to cardiovascular disease and other problems.

This article looks at the health benefits of copper, sources, and any potential health risks.

Fast facts about copper:

  • Copper is necessary for a range of bodily functions.
  • Copper deficiency is rare except in specific conditions, such as Menkes disease.
  • Copper supplements are not usually necessary and may lead to an imbalance.
  • A copper imbalance has been linked to Alzheimer's disease.
  • Anyone who is considering copper supplements should first speak to a doctor.

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Copper is a useful material, but it is also a valuable mineral found in food.

Copper is an essential nutrient for the body.

Together with iron, it enables the body to form red blood cells.

It helps maintain healthy bones, blood vessels, nerves, and immune function, and it contributes to iron absorption.

Sufficient copper in the diet may help prevent cardiovascular disease and osteoporosis, too.

Cardiovascular health

Low copper levels have been linked to high cholesterol and high blood pressure. One group of researchers has suggested that some patients with heart failure may benefit from copper supplements.

Animal studies have linked low copper levels to CVD, but it remains unclear if a deficiency would have the same impact on humans.

Neuron signalling

In 2016, Prof. Chris Chang, a chemist who is part of the Sackler Sabbatical Exchange Program at Berkeley, CA, devised and used a fluorescent probe to track the movement of copper in and out of nerve cells.

Prof. Chang says: "Copper is like a brake or dimmer switch, one for each nerve cell."

His team found that, if high amounts of copper enter a cell, this appears to reduce neuron signaling. When copper levels in that cell fall, signaling resumes.

Immune function

Too little copper can lead to neutropenia. This is a deficiency of white blood cells, or neutrophils, which fight off infection.

A person with a low level of neutrophils is more likely to get an infectious disease.

Osteoporosis

Severe copper deficiency is associated with lower bone mineral density and a higher risk of osteoporosis.

More research is needed on how marginal copper deficiency may affect bone health, and how copper supplementation might help prevent and manage osteoporosis.

Collagen production

Copper plays an important role in maintaining collagen and elastin, major structural components of our bodies. Scientists have hypothesized that copper may have antioxidant properties, and that, together with other antioxidants, a healthful intake may help prevent skin aging.

Without sufficient copper, the body cannot replace damaged connective tissue or the collagen that makes up the scaffolding for bone.

This can lead to a range of problems, including joint dysfunction, as bodily tissues begin to break down.

Arthritis

Animal studies have indicated that copper may help prevent or delay arthritis, and people wear copper bracelets for this purpose. However, no human studies have confirmed this.

Antioxidant action

Copper may also have an antioxidant function. It may help reduce the production of free radicals.

Free radicals can damage cells and DNA, leading to cancer and other diseases.

The recommended daily allowance (RDA) is around 900 micrograms (mcg) a day for adolescents and adults.

The upper limit for adults aged 19 years and above is 10,000 mcg, or 10 milligrams (mg) a day. An intake above this level could be toxic.

Both copper deficiency and copper toxicity are rare in the United States (U.S).

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A high intake of vitamin C supplements can cause copper deficiency.

While a copper deficiency is rare, some health conditions and other factors can increase the risk.

These include:

  • genetic defects of copper metabolism
  • absorption problems
  • too high an intake of zinc or vitamin C supplements
  • some conditions, such as central nervous system (CNS) demyelination, polyneuropathy, myelopathy, and inflammation of the optic nerve

Since copper is stored in the liver, deficiencies develop slowly over time.

Zinc and vitamin C

A high intake of zinc (150 mg a day or above) and vitamin C (over 1,500 mg a day) may induce copper deficiency by competing with copper for absorption in the intestine.

Causes of deficiency in infants

Copper deficiency has been seen in infants who consume cow's milk instead of formula. Cow's milk has a low copper content. Children under 1 year should be ideally breast fed and if not, fed manufactured formula. Cow's milk does not have the required nutrients for a human infant.

Low levels of copper can lead to:

Metabolic diseases can affect the way the body absorbs vitamins and minerals.

Menkes disease

Menkes disease, an X-linked recessive disorder, adversely affects how the brain metabolizes copper. This can result in failure to thrive and neurodevelopmental delays in infants from around 6 to 8 weeks of age. A child with this disease may not survive to the age of 3 years.

Subcutaneous copper injections can help normalize blood copper levels, but whether these help to normalize brain copper levels depends on the type of genetic mutation involved.

One clinical trial has found that treating infants before symptoms begin may help to improve gross motor skills, fine motor and adaptive skills, personal and social skills, and language neurodevelopment in children. It also improved growth.

Other effects of copper deficiency

Copper deficiency has also been linked to:

  • an increased risk of infection
  • osteoporosis
  • depigmentation of the hair and skin
  • anemia, as copper contributes to the creation of red blood cells

Too little or too much copper can damage brain tissue.

In adults, neurodegeneration has been observed as a result of a copper imbalance. This may be due to a problem with the mechanisms involved in metabolizing copper for use in the brain.

High levels of copper can lead to oxidative damage in the brain. In Wilson's disease, for example, high levels of copper collect in the liver, brain, and other vital organs.

Possible link with Alzheimer's

An excessive accumulation of copper has also been associated with Alzheimer's disease.

Prof. Chang and colleagues have hypothesized that when copper accumulates in unusual ways, this may cause amyloid plaques to build up on a nerve cell.

A buildup of amyloid plaques can lead to Alzheimer's and other neurodegenerative disorders.

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Cashew nuts contain copper.

Copper is found in a wide variety of foods.

Good sources include:

  • oysters and other shellfish
  • whole grains
  • beans
  • potatoes
  • yeast
  • dark leafy greens
  • cocoa
  • dried fruits
  • black pepper
  • organ meats, such as kidneys and liver
  • nuts, such as cashews and almonds

Most fruits and vegetables are low in copper, but it is present in wholegrains, and it is added to some breakfast cereals and other fortified foods.

Copper supplements are available, but it is best to first try to obtain essential vitamins and minerals through food in order to reduce the risk of an imbalance. Very few people need to take a copper supplement.

Additionally, the nutrients in food work together to create an effect that is more significant than that achieved by taking individual nutrients in isolation.

Most multivitamin supplements contain 2 mg of copper, which is halfway along the Safe and Adequate Range of Intake fixed by the Food and Nutrition Board (FNB).

Copper supplements can interact with the following:

  • birth control pills and hormone therapy
  • non-steroidal anti-inflammatories (NSAIDS), such as aspiring and ibuprofen
  • penicillamine, used to reduce copper levels in Wilson's disease
  • allopurinol, a gout treatment
  • cimetidine, or Tagamet, use for gastric ulcers and gastric reflux
  • zinc supplements

These products may reduce or increase levels of copper in the blood, leading to an imbalance.

Copper toxicity

No adverse effects have been reported from normal dietary consumption of copper, but symptoms can appear if there is:

  • excessive supplementation
  • high levels of copper in drinking water, such as well water or water that is stored in copper pipes
  • exposure to chemicals containing high levels of copper
  • use of copper cooking pots

Signs of copper toxicity include:

  • nausea, vomiting, diarrhea, and stomach pain
  • headache
  • dizziness
  • weakness
  • a metallic taste in the mouth

More serious effects are rare, but they include:

Increased serum copper levels have been linked with a higher risk of cardiovascular disease.

Water that contains more than 6 mg of copper per liter may cause stomach problems. If drinking water appears to trigger symptoms, the individual should see about getting it tested.

A copper deficiency can have negative effects on health, but it is rare in healthy people who follow a balanced diet.

Nutrient requirements should first be met through foods, and then supplements can be used as a backup.

Anyone who is considering taking a supplement should first check with a health care provider. Supplements are not monitored by the food and drug administration (FDA) for quality or purity.