Other common name(s): none

Scientific/medical name(s): Cu, cupric oxide, copper sulfate, copper gluconate, copper picolinate, cupric acetate, alkaline copper carbonate

Description

Copper is a required nutrient. It is found naturally in foods such as seafood, liver, green vegetables, whole grains, wheat bran, lentils, and nuts. Copper helps regulate blood pressure and heart rate and is needed to absorb iron from the gut. It is used to make many important compounds in the body.

Overview

Some laboratory and animal studies have found that copper has antioxidant properties and may have some anti-cancer effects. Other studies have found that high copper levels in the blood were linked with cancer and other diseases. More extensive human studies are needed to determine what role copper may play in the prevention or treatment of cancer.

How is it promoted for use?

There are claims that copper aids in the healing process, helps to expel toxins from the body, and helps prevent heart problems. Copper is also used in some preparations of Iscador, a commercially prepared mistletoe extract sold as a complementary therapy in Europe for tumors of the liver, gallbladder, stomach, and kidneys.

There are also claims that copper actually promotes cancer growth. Proponents of this theory recommend a diet low in copper and the use of chelating agents that bind to copper and promote its elimination from the body (see our document, "Chelation Therapy").

What does it involve?

Copper supplements are available in pill or capsule form. Copper is often added to vitamin supplements. However, most people are able to get enough copper in their bodies by eating balanced meals. Fruits and vegetables can provide up to 30% of a person's total copper intake. Some copper is also present in drinking water, and copper pipes can leach extra copper into the water they carry.

The minimum recommended dietary allowance (RDA) for copper is 0.9 milligrams per day for most adults, 1 milligram for pregnant women, and 1.3 milligrams for women who are breast-feeding. The RDA is enough to meet the needs of most people in these groups. Some people may not get enough copper from foods, especially if they take zinc supplements, which can partly block copper absorption. Large doses of vitamin C supplements can also block copper uptake. People who take zinc supplements or large doses of vitamin C may need to take extra copper to absorb enough. Those with malabsorption diseases or malnutrition may also need extra copper.

What is the history behind it?

While research into the antioxidant properties of copper is quite recent, healing properties have long been attributed to copper in folk medicine. Some people wear copper bracelets, for example, to help with arthritis. Today, many multivitamins and other herbal and mineral supplements include copper.

What is the evidence?

Copper is a trace mineral that is needed for many important body processes. Animal studies have shown that copper is useful in maintaining antioxidant defenses. Antioxidants block the actions of free radicals, activated oxygen molecules that can damage cells. While the role of copper in the cancer process is still unclear, copper complexes have been shown to have anti-cancer properties in laboratory studies.

Other laboratory and animal studies suggest that high copper levels may be linked to liver cancer and brain tumors. More recently, many studies have shown that patients’ blood copper levels are higher in several types of cancer and other diseases. To add to the confusion, blood tests can show high copper levels even when there is little copper in the tissues. These high copper levels may be due to injury, disease, or inflammation.

Because copper is needed to form new blood vessels, and because cancer needs new blood vessels in order to grow, some researchers are interested in copper’s possible impact on cancer. One group of researchers looked at whether a copper-lowering drug could help patients with advanced kidney cancer. Some patients’ cancer stopped growing during the 6-month treatment period. A few people had low white blood counts during treatment, requiring that treatment be stopped until they recovered. This was a small study, and further research is needed to find out whether copper can help more people with advanced cancer.

Another study noted high copper levels in the blood of people who died from heart disease. It is not known whether the laboratory tests accurately reflected copper levels in the body tissue or exactly what caused the high levels. In contrast, a recent study gave copper supplements to healthy women with no signs of copper deficiency. Their cholesterol and triglyceride levels improved, as did some other markers of heart disease risk. This small study did not look at actual heart disease, however. Further research is required to determine whether copper can affect heart disease risk.

Many people wear copper bracelets for their arthritis, and some people report improvements in their arthritis symptoms. However, available scientific evidence does not support claims that the bracelets are effective. A gel form of copper salicylate (an aspirin-copper compound) was found to be no more effective at relieving pain than sham gel, although the copper gel produced more rashes. Further research may help determine whether any form of copper might be helpful in arthritis.

One laboratory study showed that the white blood cells of men who had been on a low-copper diet did not attack germs as effectively as they had when the same men were receiving enough copper. An older study in a group of children recovering from malnutrition showed that those who got copper supplements had significantly fewer lung infections than those who got sham supplements. While severe copper deficiency is known to result in poorer immune function, further studies are needed to find out what effect, if any, milder deficiency might have. These studies are hindered by the fact that copper levels in the blood do not always reflect nutritional status.

There is some evidence that trace metals, including copper, iron and zinc, may have a role in forming the brain plaques associated with Alzheimer’s disease. However, there is not enough evidence to define the role of copper in this process.

At this time, it is hard to say how each nutrient or nutrient combination affects a person’s risk of cancer. On the other hand, large population studies have shown that those whose diets are high in vegetables and low in animal fat, meat, and/or calories have lower risks for some of the most common types of cancer. Until more is known about this, the American Cancer Society recommends eating a variety of healthful foods--with most of them coming from plant sources--rather than relying on supplements. Supplements may be helpful for some people, such as pregnant women, women of childbearing age, and people with restricted food intakes. If a supplement is taken, the best choice for most people is a balanced multivitamin/mineral supplement that contains no more than 100% of the "Daily Value" of most nutrients.

Are there any possible problems or complications?

This product is sold as a dietary supplement in the United States. Unlike companies that produce drugs (which must provide the FDA with results of detailed testing showing their product is safe and effective before the drug is approved for sale), the companies that make supplements do not have to show evidence of safety or health benefits to the FDA before selling their products. Supplement products without any reliable scientific evidence of health benefits may still be sold as long as the companies selling them do not claim the supplements can prevent, treat, or cure any specific disease. Some such products may not contain the amount of the herb or substance that is written on the label, and some may include other substances (contaminants). Though the FDA has written new rules to improve the quality of manufacturing processes for dietary supplements and the accurate listing of supplement ingredients, these rules do not take full effect until 2010. And, the new rules do not address the safety of supplement ingredients or their effects on health when proper manufacturing techniques are used.

Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Copper toxicity is rare, and copper supplements are considered safe when taken in recommended amounts. However, adults are advised not to take more than 10 milligrams per day due to increased risk of liver damage. The maximum recommended dosage is lower for children, depending on age. Copper overdoses can cause serious problems such as liver damage, kidney failure, coma, and death. Early symptoms of overdose may include nausea, vomiting, diarrhea, abdominal pain, problems with coordination or movement, and sleepiness. There may also be behavioral problems, such as trouble concentrating or emotional disturbances.

People with Wilson’s disease (a genetic disorder that allows copper to build up in the body) should not take copper supplements or multivitamins containing copper. Diabetics should also avoid these supplements because copper can affect blood sugar levels.

Problems may also happen when a person has too little copper. Copper is required for iron to be absorbed into the body and is necessary for babies to develop normally. Osteoporosis can develop in infants and adults with too little copper. In adults, low copper levels can result in anemia and low white blood cell counts. Low copper levels in adults have been reported to cause muscle spasms in the legs and trouble walking.

Copper can interfere with some medicines. Talk with your doctor or pharmacist about all medicines, herbs, and supplements that you are taking. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional Resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).

• Guidelines for Using Complementary and Alternative Methods

• How to Know What Is Safe: Choosing and Using Dietary Supplements

• The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

• Complementary and Alternative Methods for Cancer Management

• Placebo Effect

• Learning About New Ways to Treat Cancer

• Learning About New Ways to Prevent Cancer

References

Araya M, Olivares M, Pizarro F, Méndez Ma, González M, Uauy R. Supplementing copper at the upper level of the adult dietary recommended intake induces detectable but transient changes in healthy adults. J Nutr. 2005;135:2367-2371.

Bügel S, Harper A, Rock E, O’Conner JM, Bonham MP, Strain JJ. Effect of copper supplementation on indices of copper status and certain CVD risk markers in young healthy women. Br J Nutr. 2005;94:231-236.

Cassileth B. The Alternative Medicine Handbook: The Complete Reference Guide to Alternative and Complementary Therapies. New York, NY: W.W. Norton; 1998.

Castillo-Durán C, Fisberg M, Valenzuela A, Egaña JI, Uauy R. Controlled trial of copper supplementation during the recovery from marasmus. Am J Clin Nutr. 1983;37:898-903.

Copper. PDRhealth Web site. http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/cop_0083.shtml. Accessed June 4, 2008.

Davis CD, Feng Y. Dietary copper, manganese and iron affect the formation of aberrant crypts in colon of rats administered 3,2’-dimethyl-4-aminobiphenyl. J Nutr. 1999;129;1060-1067.

DiSilvestro RA, Sakamoto K, Milner JA. No effects of low copper intake on rat mammary tissue superoxide dismutase 1 activity and mammary chemical carcinogenesis. Nutr Cancer. 1998;31:218-220.

Eaton-Evans J, Mellwrath EM, Jackson WE, McCartney H, Strain JJ. Copper supplementation and the maintenance of bone mineral density in middle-aged women. J Trace Elem Exp Med. 1996;9:87-94.

Finefrock AE, Bush AI, Doraiswamy PM. Current status of metals as therapeutic targets in Alzheimer's disease. J Am Geriatr Soc. 2003;51:1143-1148.

Ford ES. Serum copper concentration and coronary heart disease among US adults. Am J Epidemiol. 2000;151:1182-1188.

Kelley DS, Daudu PA, Taylor PC, Mackey BE, Turnlund JR. Effects of low-copper diets on human immune response. Am J Clin Nutr. 1995;62:412-416.

Kumar N, Gross JB Jr, Ahlskog JE. Copper deficiency myelopathy produces a clinical picture like subacute combined degeneration. Neurology. 2004;63:33-39.

Higdon J. Copper. Linus Pauling Institute Micronutrient Information Center. Oregon State University Web site. http://lpi.oregonstate.edu/infocenter/minerals/copper/. Updated July 2007. Accessed June 4, 2008.

Mártin-Lagos F, Navarro-Alarcón M, Terrés-Martos C, López-G de la Serrana H, López-Martínez MC. Serum copper and zinc concentrations in serum from patients with cancer and cardiovascular disease. Sci Total Environ. 1997;204:27-35.

Milne DB, Nielsen FH. Effects of a diet low in copper on copper-status indicators in postmenopausal women. Am J Clin Nutr. 1996;63:358-364.

Percival SS. Copper and immunity. Am J Clin Nutr. 1998;67:1064S-1068S.

Redman BG, Esper P, Pan Q, Dunn RL, Hussain HK, Chenevert T, Brewer GJ, Merajver SD. Phase II trial of tetrathiomolybdate in patients with advanced kidney cancer. Clin Cancer Res. 2003;9:1666-1672.

Renault E, Deschatrette J. Alterations of rat hepatoma cell genomes induced by copper deficiency. Nutr Cancer.1997;29:242-247.

Scheinberg IH, Sternlieb I. Wilson disease and idiopathic copper toxicosis. Am J Clin Nutr. 1996;63:842S-845S.

Shackel NA, Day RO, Kellett B, Brooks PM. Copper-salicylate gel for pain relief in osteoarthritis: a randomised controlled trial. Med J Aust. 1997;167:134-136.

Spencer JW, Jacobs JJ. Complementary/Alternative Medicine: An Evidence-Based Approach. St. Louis, MO: Mosby; 1999.

Strain JJ. Putative role of dietary trace elements in coronary heart disease and cancer. Br J Biomed Sci. 1994;51:241-251.

US Congress, Office of Technology Assessment. Unconventional Cancer Treatments: OTA-H-405. Washington, DC: US Government Printing Office; 1990.

Wu T, Sempos CT, Freudenheim JL, Muti P, Smit E. Serum iron, copper and zinc concentrations and risk of cancer mortality in US adults. Ann Epidemiol. 2004;14:195-201.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 11/01/2008
Last Revised: 11/01/2008