B12 and folate deficiency dementia.

Both B12 and folate deficiency have been linked to a dementia syndrome. In the case of B12, the neurologic sequelae may precede the hematologic by months to years. Treating a B12 deficient patient with folate or conversely a folate deficient patient with B12 may exacerbate the neurologic consequences of either deficiency. Iron deficiency is a frequent concomitant of both B12 and folate deficiency, often developing during replacement therapy. Patients with borderline B12 deficiency states have shown biochemical evidence of megaloblastosis and B12 replacement is recommended for those patients.