Diet is always the best way to get any nutrient.  If your baby is suffering from an iron deficiency she is probably not getting the foods she needs.  Baby cereals are fortified with iron but many babies don't like them.  If your baby is old enough to eat real cereal, many are also fortified with iron and babies often like dry cereal (such as Cheerios) as a snack.  Red meat is an excellent source of iron.  Other options include black strap molasses, soy, dried fruit, quinoa, and beans. 

Brenna Leah Cashman, RNCP