<unk>  can cause a syndrome of anemia or pancytopenia and a neurodegeneration in humans or other mammals.  The neurodegenerative syndrome of<unk>  has been recognized for some time in ruminant animals, in which it is commonly known as “swayback.”  Affected animals develop ataxia and spasticity.
Cases of human anemia caused by<unk>  are rare, but have been known of for many years.  More recently, a syndrome similar to ruminant swayback has been seen.  Affected persons develop progressive spasticity, ataxia, and a neuropathy.  This may be accompanied by anemia as well.  The clinical syndrome is nearly identical to subacute combined degeneration, a long-recognised and relatively common condition caused by vitamin B12 deficiency.<unk>  in ruminants can be caused by<unk> -poor grazing lands or<unk> -poor feed.  In humans,<unk>  can occur through<unk> -deficient parenteral nutrition or as a result of gastric bypass surgery. The recommended daily intake of elemental<unk>  for an adult is 0.9 mg daily and typical American diets may be deficient in<unk> . Zinc competes with<unk>  for absorption by the gut.  Chronic excessive zinc consumption, such as may occur in those who overuse denture adhesive compounds, can cause<unk> .
Copper deficiency
Biotin deficiency
Zinc deficiency
Manganese deficiency 
Chromium deficiency
Vitamin D deficiency
Lead poisoning
Vitamin B12 deficiency