Copper

A trace mineral used in iron metabolism, connective tissue and nerve function. Its story is mostly told alongside zinc, because the two compete and an excess of one produces a shortage of the other.

Needed to use iron, to form connective tissue, and for nerve function and energy production.

• Liver
• Oysters and shellfish
• Dark chocolate
• Cashews and sesame
• Mushrooms

900 µg for most adults. The upper limit, past which harm becomes likely, is 10 mg.

Reference intakes are population figures. Pregnancy, illness, age and medication all move an individual’s needs, which is one of several reasons this page is information rather than advice.

Most at risk: People taking high-dose zinc for long periods, and after bariatric surgery.

Most often self-inflicted through prolonged high-dose zinc supplementation. Also after bariatric surgery, in malabsorption, and rarely from genetic causes.

Anaemia that does not respond to iron, low white cell count, bone abnormalities, and nerve damage.

Every sign here has other, often likelier, explanations. A list of symptoms is a reason to look into something, never a diagnosis.

Serum copper and ceruloplasmin are the usual tests. Both rise with inflammation, oestrogen and pregnancy, so they need interpreting in context.

Liver, shellfish, nuts, seeds, wholegrains, dark chocolate and mushrooms. Ordinary varied eating supplies it without effort.

Rarely needed on its own. The commonest reason to think about copper is to stop something else — reviewing a high-dose zinc regimen rather than adding a second supplement.

Nausea and liver damage. Wilson disease causes accumulation regardless of intake.

Interactions: High zinc intake blocks it — the commonest cause of copper deficiency in practice.