How do I prevent anemia? Cook with cast iron?

Multivitamin. Most commonly anemias are deficiency driven- vitamin b12, folate (folic acid) or iron. If you take a multivitamin daily you will help to replace these items. If however, you have an anemia currently, then it is better to have it evaluated then to self-treat as there are additional reasons for anemia such as thyroid dysfunction, kidney dysfunction or bone marrow dysfunction diagnosed by a physician.