Copper (Cu) is a naturally occurring element recognized as an essential trace mineral, meaning the human body requires it in small quantities for proper function. This reddish-brown metal has been utilized by humans for thousands of years due to its durability, malleability, and high conductivity. Copper is found throughout the environment, present in rocks, soil, and water, making it widely accessible for both biological systems and industrial applications. Its ubiquitous nature means it is incorporated into countless objects and processes, from the natural world to modern technology.
Copper’s Role in Biological Processes
The element functions primarily as a cofactor, assisting many enzymes in performing their biological work. One of its primary functions is in energy production, where it is a component of cytochrome c oxidase. This enzyme complex is necessary for aerobic respiration within the cell’s mitochondria, converting oxygen into water to release cellular energy.
Copper also plays a necessary role in iron metabolism, facilitating the body’s ability to utilize and transport iron. It is required for the proper function of ceruloplasmin, a protein that oxidizes iron so it can bind to its plasma carrier, transferrin, for transport. Another element is copper’s involvement in maintaining the structural integrity of tissues. It is a cofactor for lysyl oxidase, an enzyme that forms cross-links between collagen and elastin fibers, the main components of strong connective tissue found in blood vessels, bones, and skin.
Foods Rich in Copper
Since the body cannot produce copper on its own, it must be obtained through diet to meet the Recommended Dietary Allowance of 900 micrograms per day for adults. The highest concentration of copper is found in organ meats, with a single serving of beef liver providing well over the entire daily requirement. Seafood, particularly shellfish like oysters and crab, are also exceptionally rich sources of the mineral.
For those seeking plant-based sources, nuts and seeds are nutrient-dense options. Legumes and certain vegetables also contribute significantly to copper intake.
- Nuts and seeds, such as cashews and sunflower seeds
- Legumes, including chickpeas and lentils
- Shiitake mushrooms
- Dark leafy greens
- Dark chocolate that is 70% cocoa or higher
Everyday Non-Dietary Sources
Copper’s high electrical conductivity makes it fundamental to electrical wiring in homes and electronic devices globally. In construction, its resistance to corrosion means it is widely used for water pipes and plumbing systems. If the water traveling through these pipes is acidic, small amounts of copper can leach into the drinking water, especially in new or recently installed plumbing.
The metal is a primary component in several common alloys found in everyday objects. Brass, an alloy of copper and zinc, is often used for door handles, musical instruments, and plumbing fixtures. Bronze, a mixture of copper and tin, is prized for its hardness and is used in sculptures, bearings, and marine hardware.
The agricultural sector relies on copper compounds, such as copper sulfate and copper hydroxide, which are utilized as fungicides and bactericides. These treatments release positively charged copper ions onto plant surfaces to disrupt the cellular processes of pathogens. In the kitchen, copper cookware is valued for its superior heat transfer, but most modern versions are lined with stainless steel or tin to prevent the reactive copper from leaching into acidic foods during cooking.
The Body’s Management of Copper Levels
The body possesses refined mechanisms to maintain copper homeostasis, which is the balance between absorbing enough copper and eliminating any excess. The liver is the central organ in this process, taking up newly absorbed copper and incorporating it into proteins like ceruloplasmin before distributing it throughout the body. Any surplus copper that is not needed is excreted from the liver primarily into the bile.
Disruptions to this careful balance are usually the result of rare genetic conditions that affect copper-transporting proteins. Menkes disease is a disorder that impairs the body’s ability to transport copper out of the intestine, leading to a systemic copper deficiency. Conversely, Wilson’s disease prevents the liver from properly excreting excess copper into the bile, resulting in a toxic accumulation in the liver, brain, and other organs.