Causes include Severe childhood protein deficiency Persistent infantile diarrhea (usually associated with a diet limited to milk) Severe malabsorption (as in sprue or cystic fibrosis) Bariatric surgery (where vitamin B12 deficiency may also be present) Excessive zinc intake Deficiency may cause neutropenia, impaired bone calcification, myelopathy, neuropathy (with symptoms similar to vitamin B12 deficiency), and hypochromic anemia not responsive to iron supplements.