Some authorities believe that our average intake is higher than our actual needs, that low intakes are uncommon, and that toxicity is a potential problem. Others believe that a low intake is more common because soil depletion has decreased the copper level in many foods and because many people avoid natural, copper-containing foods.
Copper is found in many natural foods in small amounts with oysters and nuts being the richest sources. Foods with good supplies of copper are the whole grains, particularly buckwheat and whole wheat; shellfish, such as shrimp and other sea food; liver and other organ meats; most dried peas and beans; and nuts, such as Brazil nuts, almonds, hazelnuts, walnuts, and pecans. Oysters have high amounts, about five times as much as other foods. Soybeans supply copper, as do dark leafy greens and some dried fruits, such as prunes; cocoa, black pepper, and yeast are also sources. In addition to food sources, copper can come from water pipes and cookware.
The RDA for copper is 2mg per day for adults, 1-2mg for children and 0.5-1mg for infants. The average adult intake had been estimated at 2.5-5mg per day, although there are reports suggesting lower levels. Whenever copper is deficient, which it can be for many reasons, it should be supplemented. If you take a copper supplement, you should consider also taking zinc, unless you are treating high zinc levels or a copper deficiency.