Mineral
Copper
You can eat plenty of iron and still be anaemic if copper is short, because the enzyme that loads iron onto its transport protein is a copper enzyme. It is a small requirement with an outsized failure mode.
What it does
Copper sits at the active site of enzymes that do jobs nothing else can. Cytochrome c oxidase, the last step of the chain that extracts energy from food, is one. Lysyl oxidase, which cross-links collagen and elastin so that connective tissue and blood vessel walls hold together, is another.
Ceruloplasmin, a copper protein, oxidises iron so it can bind to transferrin and be moved around the body. Without enough copper, iron accumulates where it is stored and never reaches the marrow — producing an anaemia that iron supplements do not fix.
It is also needed for the pigment melanin, and for several steps in neurotransmitter synthesis.
How much you need
| Who | Per day | Note |
|---|---|---|
| Infants, 0–6 months | 200 µg | Adequate Intake |
| Infants, 7–12 months | 220 µg | Adequate Intake |
| Children, 1–3 years | 340 µg | — |
| Children, 4–8 years | 440 µg | — |
| Children, 9–13 years | 700 µg | — |
| Ages 14–18 | 890 µg | — |
| Adults, 19 and over | 900 µg | — |
| Pregnancy | 1,000 µg | — |
| Breastfeeding | 1,300 µg | — |
Micrograms, not milligrams. Copper is needed in quantities about a thousand times smaller than calcium, and the upper limit for adults is 10 mg — roughly eleven times the recommendation.
From our own data
The foods highest in copper
Liver and shellfish lead by a wide margin, followed by seeds, nuts, cocoa and wholegrains. Dark chocolate is a genuine source rather than a wishful one.
- 1
Veal liver, pan-fried1,672% · DV - 2
Wild Atlantic oysters, cooked634% · DV - 3
Sesame paste468% · DV - 4
Unsweetened baking chocolate359% · DV - 5
Soy flour, full-fat324% · DV - 6
Winged beans, dry320% · DV - 7
Squid, cooked261% · DV - 8
Cashews247% · DV - 9
Vine leaves, canned205% · DV - 10
Sunflower seeds, unsalted203% · DV - 11
Brazil nuts194% · DV - 12
Hazelnuts192% · DV
Per 100 g, from our copy of USDA FoodData Central, against a Daily Value of 1mg. Ranked by amount, not by how much of it your body actually takes up — read the next section before you act on the order.
The table above is per 100 g. The app weighs the portion you actually ate.
What helps, and what gets in the way
Helps
- A varied diet including any of shellfish, offal, nuts, seeds or cocoa
- Wholegrains over refined, as with most trace minerals
Gets in the way
- High-dose zinc supplements — the single most common cause of copper deficiency in practice
- Very high vitamin C supplementation, modestly
- Bariatric surgery and other causes of malabsorption
The zinc interaction is the one worth knowing. Zinc induces a gut protein called metallothionein, which binds copper and carries it out with the shed cells. Taking 50 mg of zinc a day for months — a dose sold over the counter — can produce a copper deficiency anaemia that looks exactly like iron deficiency and does not respond to iron.
Who tends to fall short
Groups where intake or absorption is commonly lower than the reference. It is a list of populations, not a list of symptoms — it cannot tell you anything about yourself.
- People taking high-dose zinc supplements over long periods
- People after gastric bypass or other bariatric surgery
- Infants fed cow’s milk exclusively, which is low in copper
- People with Menkes disease, a rare inherited transport disorder
Cook it
Dark chocolate and toasted seed bark
Makes one tray; twenty minutes plus setting
Ingredients
- 200 g dark chocolate, 70% or higher
- 3 tbsp sunflower seeds
- 3 tbsp pumpkin seeds
- 2 tbsp sesame seeds
- A pinch of flaky salt
Method
- 1Toast the seeds separatelyThey are different sizes and burn at different rates. Sesame goes first and fastest — thirty seconds past golden and it is bitter.
- 2Melt gentlyA bowl over barely simmering water, off the heat before the last pieces have gone. Chocolate seizes above about 50°C and there is no recovering it.
- 3Spread thinOnto baking paper, about 5 mm. Thicker and it is a slab rather than a bark, and it takes a hammer to break.
- 4Scatter and setSeeds and salt over while the chocolate is still wet, then an hour at room temperature. The fridge makes it bloom grey.
Cocoa and seeds are both genuinely good copper sources, which makes this one of the few recipes on this site that is also a confection.
Sources
- NIH Office of Dietary Supplements — Copper
- Dietary Reference Intakes for Vitamin A, Vitamin K, Copper, Iron, Zinc and others
- USDA FoodData Central
This page is education, not medical advice. It does not diagnose anything and it is not a substitute for a clinician who knows your history. If you think you are short of copper, the answer is a blood test and a conversation, not a supplement bought on the strength of an article.
Every food above, and 12,601 more, with the full panel — in the app.