Copper: needs, supplements and excess risk

Copper is an essential trace mineral involved in energy production, iron metabolism, connective tissue, the nervous system and immunity. A physiological role does not prove that extra copper improves health when intake is adequate. [1]

EFSA proposes adequate intakes of 1.6 mg/day for adult men, 1.3 mg/day for adult women and 1.5 mg/day during pregnancy and lactation. US NIH reference values differ: 0.9 mg/day for adults, 1.0 mg during pregnancy and 1.3 mg during breastfeeding. These are population references, not personal prescriptions. [1][2]

Copper is found in shellfish, organ meats, nuts, seeds, whole grains, chocolate, potatoes, mushrooms, avocado, chickpeas and tofu. Most adults can meet needs through varied food. Drinking water can contribute when copper plumbing leaches metal; WHO gives a 2 mg/L guideline for drinking water. [1][3]

Deficiency is uncommon but may occur with malabsorption, digestive surgery, severe undernutrition, genetic disorders or prolonged high-dose zinc, which can reduce copper absorption. Symptoms are nonspecific, and blood copper or ceruloplasmin require clinical interpretation. [1]

Common supplement forms include cupric oxide, sulfate, gluconate and amino-acid chelates. No form has proven generally superior in bioavailability or clinical outcome. Read the elemental copper amount and add every product source. [1]

Regularly high intake can cause nausea, vomiting, abdominal pain, cramps, diarrhoea and liver damage. NIH sets an adult upper limit of 10 mg/day from all sources; this is not a target dose. Wilson disease causes copper accumulation and requires specialist medicines, not a copper cure. [1][6]

Cochrane found moderate-certainty evidence of little or no cognitive benefit from long-term zinc and copper supplementation in cognitively healthy adults. Do not turn normal nutrient functions into promises against fatigue, arthritis, cardiovascular disease or dementia. [5]