Copper

Foods high in copper include legumes, mushrooms, chocolate, nuts and seeds, and liver(2). Due to their relative abundance in the diet, bread, potatoes and tomatoes also make substantial copper contributions (2).

An inadequate copper intake has adverse effects on glucose and cholesterol metabolism, blood pressure control and heart function, immunity and bone mineralization (2). Low copper is associated with osteoporosis, also in infants and children (5, 6). It has been shown that copper administration can improve bone mineral density in post-menopausal women, though it is unknown whether the osteoporosis itself is due to copper deficiency (2).

Overt copper deficiency is rare in humans. Symptoms include normocytic, hypochromic anaemia, leucopoenia and neutropenia, and osteoporosis in children (3). The impact of diet may be particularly pronounced in neonates as digestive function and homeostatic regulation of biliary copper are immature (2).

Copper toxicity is relatively rare, since humans have evolved with precise homeostatic mechanisms for copper due to its reactivity (2). Copper exists almost always bound to proteins. People most at risk are those with a hereditary defect in copper homeostasis (Menkes’ disease), characterised by a reduced copper uptake and placental copper transport (3). Those with Wilson’s disease (see below) are also at higher risk of copper toxicity due to liver damage resulting from the disease (3).

Idiosyncratic copper toxicity is otherwise usually acute and has been associated with copper salts in supplements and drinking water (3); symptoms include gastrointestinal distress. Alternatively, exposure can be through metal fumes, bringing about an influenza-like syndrome (7).

is a rare autosomal-recessive disorder of a copper-transporting ATPase resulting in abnormal copper storage (5). Its global prevalence is estimated to be 1:30,000 (8). The defect results in a failure to excrete copper effectively in bile, and an impaired incorporation of copper into ceruloplasmin. Thus, copper is deposited in various tissues including the liver causing cirrhosis, the brain leading to neurological symptoms, the kidneys, and the eyes causing damage. Chelation therapy is very effective however liver cirrhosis and neurological damage are permanent.