Copper toxicity can result from chronic or long-term exposure to high levels of copper through contaminated food and water sources. Symptoms of this condition include diarrhea, headaches, and in severe cases, kidney failure.
Certain genetic disorders, such as Wilson’s disease, can also lead to copper toxicity.
In this article, we define copper toxicity, along with its causes, symptoms, and treatments. We also discuss ways of preventing this condition and when to contact a doctor.
About copper
Copper is a heavy metal and an essential mineral that supports the following body functions:
- metabolizing iron
- forming enzymes that produce energy
- building connective tissues
- developing new blood vessels
- balancing hormones that make nerve cells
- regulating gene expression
- promoting healthy immune system functioning
While many plant and animal food sources naturally contain copper, the human body only stores about 50–120 milligrams (mg) of the substance. The body excretes excess copper in bile, a digestive fluid produced by the liver.
A doctor can check a person’s copper levels through blood tests. Typical copper concentrations range from 63.5–158.9 micrograms (mcg) per deciliter of blood.
The recommended dietary allowance (RDA) of copper ranges between 340–890 mcg per day for children 18 years of age or younger and 900 mcg/day for adults, according to the 2015-2020 Dietary Guidelines for Americans.
According to the National Institutes of Health (NIH), adults should not consume more than 10 mg of copper per day. Excessive amounts of this metal can lead to adverse health effects.
Causes
People rarely develop copper toxicity. However, it can occur when a person ingests high levels of the substance from contaminated water, food, or air.
According to the Agency for Toxic Substances and Disease Registry, industries released an estimated 1.4 billion pounds of copper into the environment in 2000.
Copper in water
In 1991, the Environmental Protection Agency (EPA) published a regulation called the Lead and Copper Rule, which states that public drinking water should not contain more than 1.3 mg of copper per liter of water.
Tap water that runs through copper pipes or brass faucets can absorb copper particles, particularly if these parts have corroded. Farm and industrial waste can also run off into public reservoirs, contaminating drinking water.
The Centers for Disease Control and Prevention (CDC) recommend flushing household water systems contaminated with copper before drinking or cooking with water. They also suggest running water through each faucet for at least 15 seconds if the faucet remains unused for six or more hours.
Copper in food
Many foods naturally contain copper. Examples of copper-rich foods include:
- animal meat, such as beef and turkey
- organ meats, such as liver and giblets
- shellfish, such as oysters, crab, and lobster
- grains, such as millet and cereal
- vegetables, such as spinach, asparagus, and tomatoes
- dairy products, such as milk and yogurt
- seeds, nut, and legumes
- tofu
- potatoes
- mushrooms
- raw avocado
- chocolate
People eat and drink about 1 mg of copper every day. The body effectively prevents high levels of the substance from entering the bloodstream. However, a person can develop copper toxicity if they eat food served on or prepared with corroded copper cookware, dishes, or utensils.
Copper in air
Trace amounts of copper exist in the air. On average, air contains 1–200 nanograms (ng) of the metal per cubic meter (m3) of air. However, copper concentrations can reach as high as 5,000 ng/m3 in areas near copper smelters and industrial mines.
People who work in agriculture, water treatment, and mining industries may breathe copper particles and fumes during a workday.
The Occupational Safety and Health Administration state that copper dust concentrations in workroom air should not exceed 1 mg/m3 during an 8-hour shift.
Medical conditions
Medical conditions that reduce the liver’s ability to remove excess copper from the body can lead to copper toxicity. Some of these conditions include:
- Wilson’s disease, a rare genetic disorder involving mutations of the ATP7B gene, which moves excess copper into bile
- Menkes disease, an inherited disorder due to a mutation in the ATP7a gene, which transports copper throughout the body.
- liver disease
- hepatitis, or inflammation of the liver
- Hodgkin lymphoma, or cancer of the lymph nodes
- leukemia, or blood cell cancer
- brain cancer
- liver cancer
- breast cancer
- diabetes
Copper IUDs
Intrauterine devices (IUDs) are long-acting, reversible birth control devices. They consist of a T-shaped piece of plastic with thin threads.
The IUD’s arms hold itself in place inside the uterus, while its core contains a synthetic form of the hormone progesterone. In non-hormonal IUDs, a thin copper wire wraps around the body.
The copper wire triggers inflammation in the uterus, which kills sperm and eggs.
Current evidence does not suggest that copper IUDs increase the risk of copper toxicity. In a 1980 study, researchers found that long-term use of these devices did not change copper levels present in blood or urine.
In a more recent 2017 rat study, researchers observed the effects of copper IUD exposures at 20, 40, and 60 times the recommended dosages. After 26 weeks, the researchers found no signs of copper toxicity or organ damage.
However, the rats had increased white blood cell counts, which the researchers explained as part of the body’s natural inflammatory response to copper. These findings support the safety of long-term copper IUD use.
However, these results are not directly applicable to humans. With this in mind, the researchers encourage further clinical studies.
According to The Academy of Breastfeeding Medicine, copper IUDs have no known impact on breast milk production or secretion.
Symptoms
Copper is present in almost every type of tissue in the body. High concentrations of the substance accumulate in the:
- bones
- muscles
- brain
- liver
- kidneys
Copper toxicity can lead to various symptoms, including:
- stomach pain
- nausea and vomiting
- diarrhea
- blue- or green-colored stool
- dark, sticky stool containing blood
- headache
- dizziness
- fatigue
- fever or chills
- aching muscles
- extreme thirst
- tachycardia or abnormally fast heart rate
- changes in taste that can lead to decreased appetite or anorexia
Copper toxicity can also trigger the following neurological and psychological symptoms:
- sudden changes in mood
- symptoms of depression or anxiety
- feeling irritable or overexcited
- difficulty focusing
Copper toxicity can have severe health effects, such as:
- kidney failure
- heart failure
- loss of red blood cells
- liver disease
- brain damage
- death
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