Evidence Level
Moderate
Copper research primarily focuses on deficiency and toxicity rather than therapeutic supplementation. The most clinically relevant finding is zinc-induced copper deficiency: Prasad et al. (1978) and subsequent studies confirmed that zinc supplementation above 50mg/day for extended periods reliably induces copper deficiency, manifesting as anemia, neutropenia, and neurological symptoms. Willis et al. (2005) reported cases of copper deficiency myelopathy mimicking B12 deficiency following chronic zinc supplementation. Current clinical practice recommends 1-2mg supplemental copper whenever zinc exceeds 30mg/day.