Copper Interactions

Zinc and copper share an intestinal absorption pathway through metallothionein, so chronic high-dose zinc (50 mg or more daily) progressively depletes copper, causing anemia, neutropenia, and myelopathy. Co-supplementing copper at roughly 1 mg per 15 mg zinc preserves balance and allows long-term zinc use without copper deficiency.

Copper is required to synthesize ceruloplasmin, a ferroxidase that oxidizes ferrous iron to ferric iron so it can bind transferrin and be transported to bone marrow for hemoglobin production. Without adequate copper, dietary or supplemental iron cannot be mobilized effectively and copper-deficiency anemia develops even when iron stores are normal.