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Zinc, copper, iodine, selenium and chromium, each with a characteristic syndrome
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| Element | Deficiency | Notes |
|---|---|---|
| Zinc | Periorificial and acral dermatitis, alopecia, diarrhoea, impaired taste and wound healing, immune dysfunction | Acrodermatitis enteropathica is the inherited form |
| Copper | Anaemia, neutropenia, myelopathy resembling B12 deficiency | Excess causes Wilson disease |
| Iodine | Goitre, hypothyroidism, cretinism | Commonest preventable cause of intellectual disability worldwide |
| Selenium | Cardiomyopathy (Keshan disease), myopathy | Component of glutathione peroxidase |
| Chromium | Impaired glucose tolerance | |
| Manganese, molybdenum | Rare |
At risk: patients on long-term parenteral nutrition, after bariatric surgery, with malabsorption, alcohol dependence, or severe burns.
Two interactions worth remembering: excess zinc induces intestinal metallothionein and causes copper deficiency, which is a recognised cause of a B12-like myelopathy with normal B12; and copper deficiency is easily missed after bariatric surgery.
Wilson disease is the copper overload counterpart, with hepatic and neuropsychiatric disease, Kayser-Fleischer rings and a low caeruloplasmin.