Copper (Cu)

What is copper?

Copper is an important mineral that supports our red blood cells, immune system, brain health, and skin, among other things. We are unable to produce copper in our bodies, so we must get this mineral through our diet.

Why we need it

The functions of copper are largely attributed to its role as a cofactor, which is a substance required by an enzyme for a reaction to take place. Copper serves as a cofactor for many enzymes, including those involved in our immune system.¹ Copper is also required by antioxidant enzymes like superoxide dismutase, which protects against cell damage.² Additionally, copper is required by lysyl oxidase, an enzyme that contributes to the structure of connective tissue, helping us maintain healthy skin.¹

Another important copper-dependent enzyme is ceruloplasmin, which is involved in iron absorption.² Iron is an essential component of red blood cells, which are cells that carry oxygen throughout our bodies. This means that without copper, we would be unable to absorb iron (and thus, deliver oxygen to our tissues).

Copper also supports our brain health. Copper helps us produce neurotransmitters, which are chemical messengers that carry signals throughout the brain. Copper also helps generate energy for our brain cells, and its antioxidant effects may help protect against neurodegeneration.²

Where it’s found

Copper is found in a wide variety of foods, mainly meat, seafood, grains, and legumes. Examples of copper-rich foods include:

Organ meats
Shellfish
Nuts and seeds
Rice and pasta
Beans
Potatoes

Copper can also be taken as a supplement, either on its own or as part of a multivitamin. Additionally, we can get some copper from water, although the amount of copper in drinking water is incredibly variable.³

Daily requirements

The daily Recommended Dietary Allowance (RDA) for copper, or the amount that is likely to meet the needs of most healthy people, is 340 micrograms (mcg) for children aged 1-3 years, 440 mcg for children aged 4-8 years, 700 mcg for adolescents aged 9-13 years, 890 mcg for adolescents aged 14-18 years, and 900 mcg for adults over the age of 19.4 For pregnant or breastfeeding women, the RDA increases to 1,000-1,300 mcg per day.

If you follow a balanced, varied diet, you shouldn’t have much trouble meeting these recommendations. For reference, one cup of cooked pasta provides about 230 mcg of copper, which is about 26% of the RDA for adults.⁵

Copper deficiency

Copper deficiency can have a wide range of health consequences. It can lead to anemia, a condition characterized by low red blood cells.⁶ Copper deficiency can also cause brain and nerve damage, and it can weaken our immune system, making us more susceptible to illness and infection. Copper deficiency can negatively alter our cholesterol levels as well, and it can have dangerous consequences on our heart health. Symptoms of copper deficiency include fatigue, changes in skin color or texture, low heart rate, and loss of coordination.⁶

Certain groups of people may be at higher risk for copper deficiency. These include people with malabsorptive conditions like celiac disease, Crohn’s disease, or chronic diarrhea, as well as people living in poverty.⁶ Copper deficiency is also seen in people with Menkes disease, a genetic condition characterized by an inability to transport copper from the digestive tract into the blood.⁶

Can you get too much copper?

High amounts of copper can be harmful. Too much copper can cause gastrointestinal issues such as cramping, stomach pain, nausea, and vomiting.³ Copper toxicity can also cause liver damage, which can be life-threatening in severe cases.⁶

Copper toxicity from food is unlikely. Instead, it’s typically caused by genetic conditions like Wilson’s disease, a condition characterized by an inability to properly clear copper from the body.³ In some cases, copper toxicity is caused by drinking water that has excessive amounts of copper, as a result of issues in plumbing systems.³

To prevent toxicity, a Tolerable Upper Intake Level (UL) has been established for copper. The UL for copper is 10,000 mcg per day for adults.⁴ This value represents the maximum amount of copper that is unlikely to cause harm.

Fun facts

Ever wonder why apples turn brown once they’re cut open? Copper plays a role! The enzyme polyphenol oxidase (PPO), which catalyzes the browning reaction, requires copper to function. In fact, some of the methods used to prevent fruit from browning work by targeting the copper in PPO.⁷

Copper has an interesting relationship with zinc, another essential mineral. Copper and zinc are absorbed in our digestive tract through the same mechanism, via a protein called metallothionein. When zinc is present in high amounts, it can lower the amount of copper that we absorb. Because of this, excessive zinc consumption is a possible cause of copper deficiency.