Foods high in copper, ranked by micrograms

The daily copper target is 900 mcg for adults, and beef liver, oysters, dark chocolate, cashews, and seeds are the densest sources. The mcg-per-serving ranking, why one serving of liver covers a week, and how too much zinc can drain it.

1. 01

   Beef liver: ~12,000 mcg per 3 oz, the outlier

   Beef liver is the single densest source by a wide margin: a 3 oz serving carries roughly 12,000 mcg of copper, more than a week's worth of the 900 mcg target in one sitting (USDA). Liver concentrates copper because it is the body's main storage organ for the mineral in animals, just as it is in humans. This is the rare food where a little goes a very long way, so a serving once or twice a month is a reliable top-up rather than something to eat weekly. The same portion also delivers extreme amounts of vitamin A and B12, which is the other reason to keep liver occasional rather than routine.

2. 02

   Oysters and shellfish: ~4,850 mcg per 3 oz

   Cooked oysters supply ~4,850 mcg of copper per 3 oz, several times the daily target in one modest serving, with Dungeness crab (~624 mcg per 3 oz) and other shellfish contributing usefully further down (USDA; NIH ODS). Shellfish concentrate copper along with zinc, selenium, and iodine, so a serving covers a cluster of trace minerals at once. Oysters in particular carry so much copper that a few of them clear the day comfortably, which makes them the most practical dense source for anyone who does not eat organ meats.

3. 03

   Nuts and seeds: ~290-630 mcg per ounce

   Cashews (~629 mcg per oz) and sunflower seeds (~615 mcg per oz) lead the plant sources, with sesame seeds and tahini, hazelnuts, and almonds (~290 mcg) filling in behind (USDA). An ounce of cashews covers roughly two-thirds of the daily target, which makes a handful of mixed nuts one of the easiest ways to reach the number without animal foods. Seeds and nuts are the backbone of copper intake on a plant-based diet, and because they arrive with magnesium, healthy fats, and plant protein, they do more than one job per serving.

4. 04

   Shiitake mushrooms and potatoes: ~650-675 mcg per serving

   Cooked shiitake mushrooms carry ~650 mcg of copper per half cup, and a medium potato eaten with the skin supplies ~675 mcg, each covering the better part of a day in one ordinary portion (USDA). These are the quiet staples that keep copper intake steady in people who eat neither organ meats nor shellfish. Mushrooms are unusually copper-dense for a vegetable, and potatoes deliver most of their copper in and just under the skin, which is one more reason to leave it on rather than peel it away.

5. 05

   Dark chocolate and cocoa: ~500-940 mcg per ounce

   Cocoa is genuinely copper-rich: an ounce of 70-85% dark chocolate provides ~500 mcg, and unsweetened baking chocolate or cocoa powder reaches ~900-940 mcg per ounce (USDA). This is the rare case where a small amount of a treat food makes a real nutritional contribution, since an ounce of good dark chocolate delivers roughly half to a full day of copper. It is also a large part of why cocoa scores so high in our roundup of foods high in antioxidants, as the same flavanols travel alongside the mineral. The catch is portion: chocolate brings sugar and calories, so it is a bonus source, not a base to build on.

6. 06

   Legumes and whole grains: ~350-580 mcg per cup

   Cooked chickpeas (~578 mcg per cup), lentils (~497 mcg), and other beans, plus whole grains like quinoa, buckwheat, and whole wheat, form the dependable middle of the ranking (USDA). None is a standout on its own, but a cup of legumes covers more than half the daily target and arrives with fiber, potassium, and plant protein, so building meals around beans and intact grains keeps copper topped up as a side effect. This is why plant-forward diets are rarely short on copper as long as they include legumes, nuts, and whole grains rather than refined staples.

7. 07

   Why zinc, not food, is the real risk

   The most common threat to copper status is not a poor diet but high-dose zinc. Zinc and copper compete for absorption, and chronic zinc intake above roughly 40 mg/day, the tolerable upper limit, induces a gut protein called metallothionein that traps copper and blocks it from entering the body (NIH ODS). Long-running use of high-strength zinc lozenges or supplements is the textbook cause of acquired copper deficiency, which shows up as an anemia unresponsive to iron plus a low white-cell count. The fix is not more copper but less supplemental zinc: staying at or below 40 mg/day of zinc from supplements keeps the two minerals in balance and protects copper status.