Copper is a naturally occurring metal found in soil, water and rocks. Nutritionally, it is an essential trace mineral found in certain foods and supplements. It works to help various enzymes that produce energy for the body, break down and absorb iron, and form red blood cells, collagen, connective tissue, and brain neurotransmitters. Copper also supports normal brain development and immune function, and is a component of superoxide dismutase, an antioxidant enzyme that dismantles harmful oxygen ‘free radicals’. Copper is absorbed in the small intestine and is found primarily in bone and muscle tissue.
GDR: The Recommended Dietary Allowance (RDA) for adults 19 years and older is 900 micrograms per day for both men and women. Pregnancy and breastfeeding in adults 19 years and older require 1300 micrograms per day, with a slightly lower amount of 1000 micrograms per day in young people 14 to 18 years old.
UL: The tolerable upper intake level (UL) is the maximum daily intake unlikely to cause adverse health effects. The UL for copper for adults 19 years and older and pregnant and breastfeeding women is 10,000 micrograms per day.
Copper and Health
Because dozens of enzymes use copper to perform metabolic processes throughout the body, it is believed that both excess and deficiency of copper can interrupt these normal processes and a stable level is necessary for optimal health. The body is generally good at stabilizing copper levels (absorption increases if copper intake is low, and vice versa).  Abnormal copper levels result from genetic mutations, aging, or environmental influences that can predispose to conditions such as cancer, inflammation, and neurodegeneration. 
Copper may have “pro-oxidant” effects that can cause stress and damage cells. The muscles of the heart contain high concentrations of copper and can be negatively affected by a deficiency or toxicity of the mineral.  Both conditions have been linked to atherogenesis, the early buildup of plaque in the heart arteries. [3,4] Some cohort studies show an association with higher self-reported copper intakes and lower blood pressure and LDL cholesterol, as well as an increased risk of heart disease with copper deficiency. [3,5] Other cohort studies show an increased risk of death from cardiovascular disease in people with higher blood levels of copper compared to lower levels, although it should be noted that the higher blood levels in these studies remained within a normal range. [4,6] Due to these mixed results, more research is needed before drawing any conclusions about the cardiovascular effect of copper.
Some research shows that people with higher copper levels have a lower risk of Alzheimer’s disease (AD), but both low and high blood copper levels have been reported in the brains of people with AD. Alzheimers.  A meta-analysis showed that people with AD had higher serum copper levels than those without AD.  However, a double-blind, placebo-controlled trial failed to show that copper supplements given for 12 months improved cognition in participants with mild AD.  Additionally, prospective observational studies have not found that self-reported dietary and total copper intakes are associated with cognitive decline.  Further research is needed to better understand if and how high or low copper levels are associated with AD risk.
Copper may play a role in cancer for several reasons. It supports angiogenesis, the growth of blood vessels that feed a tumor, and activates signaling enzymes and proteins used by cancer cells. [9,10] An emerging area of research has focused on the role of copper in metastatic cancer cells (these are cells that break away from a primary tumor and spread to other areas of the body).  Copper levels in these aggressive cells were found to be higher than in non-metastatic cancer cells. Intentionally depleting copper levels by blocking its bioavailability can reduce the energy these cells need to travel through the body. Chelation treatments that bind copper and inactivate it are being researched. 
Copper is found in greatest amounts in protein foods like organ meats, shellfish, fish, nuts and seeds as well as whole grains and chocolate. The absorption of copper in the body will increase if the diet contains less copper and will decrease if the body has enough.
Signs of deficiency and toxicity
Copper deficiency is rare in the United States in healthy people and occurs primarily in people with genetic disorders or malabsorption problems such as Crohn’s disease and celiac disease. A genetic condition called Menkes disease interferes with copper absorption, leading to a severe deficiency that could become fatal without copper injections. Additionally, it is possible to create a copper deficiency by taking high doses of zinc supplements which can block copper absorption in the small intestine.
Signs of deficiency include:
- High cholesterol
- Osteoporosis, bone fractures
- Increase in infections
- Loss of skin pigment
Toxicity is rare in healthy individuals because the body is efficient at excreting excess copper. This has been seen with Wilson’s disease, a rare genetic disorder, which prevents copper from leaving the body and therefore leads to high blood levels. Severe liver damage and digestive symptoms such as nausea, vomiting, diarrhea and abdominal pain may occur. Although very rare, it is possible to consume excess copper by continuously storing and then serving boiling liquids from corroded copper or brass vessels.
Did you know?
Although copper occurs naturally in water, excessive levels of copper in drinking water are usually caused by copper leaking from old, corroded household pipes and faucets. The risk is greater if the water is stagnant due to lack of use or by using hot tap water (copper dissolves more easily at higher temperatures). In these cases, exposure to excess copper can be reduced by running cold tap water for several minutes before use. It is also advisable to use only cold tap water for drinking and cooking, and to avoid drinking hot tap water.
- National Institutes of Health Office of Dietary Supplements: Magnesium Fact Sheet for Health Professionals https://ods.od.nih.gov/factsheets/Copper-HealthProfessional/. Accessed on 06/25/2022.
- Gromadzka G, Tarnacka B, Flaga A, Adamczyk A. Copper dyshomeostasis in neurodegenerative diseases – therapeutic implications. International Journal of Molecular Sciences. 2020 Dec 4;21(23):9259.
- Kunutsor SK, Dey RS, Laukkanen JA. Circulating serum copper is associated with atherosclerotic cardiovascular disease, but not with venous thromboembolism: a prospective cohort study. Impulse. 2021;9(3-4):109-15.
- Ford ES. Serum copper concentration and coronary heart disease in American adults. American Journal of Epidemiology. 2000 Jun 15;151(12):1182-8.
- Bo S, Durazzo M, Gambino R, Berutti C, Milanesio N, Caropreso A, Gentile L, Cassader M, Cavallo-Perin P, Pagano G. Associations of dietary and serum copper with inflammation, oxidative stress, and metabolic variables in adults . The food diary. 2008 Feb 1;138(2):305-10.
- Grammer TB, Kleber ME, Silbernagel G, Pilz S, Scharnagl H, Lerchbaum E, Tomaschitz A, Koenig W, März W. Copper, ceruloplasmin and long-term cardiovascular and total mortality (Ludwigshafen Risk and Cardiovascular Health Study). Free radical research. 2014 Jun 1;48(6):706-15.
- Squitti R, Simonelli I, Ventriglia M, Siotto M, Pasqualetti P, Rembach A, Doecke J, Bush AI. Meta-analysis of serum non-ceruloplasmin copper in Alzheimer’s disease. Alzheimer’s Disease Journal. 2014 Jan 1;38(4):809-22.
- Kessler H, Bayer TA, Bach D, Schneider-Axmann T, Supprian T, Herrmann W, Haber M, Multhaup G, Falkai P, Pajonk FG. Copper intake has no effect on cognition in patients with mild Alzheimer’s disease: a pilot phase 2 clinical trial. Neural transmission journal. 2008 Aug;115(8):1181-7.
- Copper Connections from Garber K. Cancer. Science. 2015 Jul 10;349(6244):129.
- Lelièvre P, Sancey L, Coll JL, Deniaud A, Busser B. The multiple roles of copper in cancer: A trace element with dysregulated metabolism, but also a target or a bullet for therapy. Cancer. 2020 Dec 1;12(12):3594.
- Ramchandani D, Berisa M, Tavarez DA, Li Z, Miele M, Bai Y, Lee SB, Ban Y, Dephoure N, Hendrickson RC, Cloonan SM. Copper depletion modulates mitochondrial oxidative phosphorylation to impair triple-negative breast cancer metastasis. Nature communication. 2021 Dec 15;12(1):1-6.
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