Recommended Nutrient Intakes for Vitamin and Minerals

Copper

Functions

Copper has many functions in the body and is an important constituent of enzymes. These diverse functions include, erythropoiesis, connective tissue synthesis, and thermogenesis. All the reactions that copper is involved in consume oxygen or oxygen radicals. Copper is also important for iron metabolism. It is essential for the mobilisation of iron as a complex with transferrin. 

Recommended Intakes

Table: Recommended Intakes for Copper (mg/day)

Food Sources

Copper is distributed in a wide range of foods. Rich sources of copper are oysters, other shellfish, liver and kidney. Other good sources are nuts, high protein cereals, dried fruit and legumes. The concentration of copper in water is variable. Copper pipes may contribute substantially to copper intake from water.

Other nutrients affect the absorption of copper. The absorption of copper is enhanced by organic nutrients such as amino acids. Conversely, absorption is inhibited by excess of ions such as zinc and iron. Dietary fibre and phytic acid do not inhibit copper absorption.

Deficiency

Copper deficiency is rare. It has been observed in malnourished children with protein energy malnutrition, in patients on long-term copper-free parenteral nutrition and in premature infants. Excess zinc interferes with copper absorption and can cause deficiency. Copper deficiency can severely disturb growth and metabolism.

Symptoms include anaemia, neutropenia, skeletal demineralisation, decreased skin tone, connective tissue aneurysms, hypothermia, neurological symptoms, and depigmented hair.

There are also defects in copper metabolism. Menkes' disease is a copper-related disorder where intestinal copper absorption is impaired. A characteristic of this disease is kinky hair.

Another condition termed acaeruloplasminaemia has been seen in patients who lack plasma caeruloplasmin. Symptoms include decreased blood levels of copper and iron, and increased iron concentrations in tissues and impaired copper absorption.

Toxicity

Copper toxicity from food is unlikely, although it can occur from supplements.  Acute copper toxicity can occur due to accidental ingestion of large doses of copper or in industrial accidents. Chronic copper toxicity is rare.

Symptoms of copper toxicity caused by small doses include vomiting and nausea. Larger doses induce hepatic necrosis and haemolytic anaemia.