Copper deficiency
Symptoms, at-risk groups, and clinical context for copper deficiency. Sourced from NIH Office of Dietary Supplements and StatPearls.
Copper deficiency is uncommon in healthy adults eating a typical diet because copper is widespread in food (organ meats, shellfish, nuts, seeds, dark chocolate). When deficiency occurs, the most common cause is excess zinc supplementation — chronic zinc intake above 40 mg/day blocks copper absorption. Other causes include bariatric surgery and rare genetic conditions.
Common symptoms
- Anemia that doesn't respond to iron supplementation (often microcytic or sideroblastic)
- Low white blood cell count (neutropenia) — increased infection risk
- Numbness, tingling, or loss of sensation in hands and feet
- Difficulty walking, balance problems (myeloneuropathy)
- Bone fragility, increased fracture risk
- Pale skin, premature graying of hair (hypopigmentation)
- Fatigue and weakness
- Vision changes (optic neuropathy in severe cases)
- Connective tissue weakness
At-risk groups
- People taking high-dose zinc supplements long-term (>40 mg/day, especially common in 'immune support' products)
- People who've had bariatric surgery, especially gastric bypass or biliopancreatic diversion
- People on long-term total parenteral nutrition without copper
- People with celiac disease or other severe malabsorption
- Excessive denture cream users (some contain zinc that blocks copper absorption)
- People with Menkes disease (rare X-linked genetic disorder of copper transport)
- Premature infants
- People with chronic diarrhea or short-bowel syndrome
When to see a doctor: Unexplained anemia that doesn't respond to iron, low white blood cell count, or progressive numbness in hands and feet warrants serum copper and ceruloplasmin testing. CRITICAL: if you take a high-dose zinc supplement long-term, you should know that 40+ mg/day of zinc can cause copper deficiency. Many cases are misdiagnosed because the connection isn't well known. The neurological damage may not fully reverse, so early recognition matters.
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Related deficiencies
Nutrients with overlapping symptoms — useful when investigating an unclear clinical picture.