I recommend you go to your doc and speak to him or her about your concerns. Just because the nutrient isn't listed on the label doesn't mean it is not in that item. Most labels only list Vit A and C, Calcium and iron. Anything other than that isn't listed. Also, if you are specifically concerned about iron, consider eating an item with vitamin c with your item with iron. Vit C helps the body absorb more iron. You can also cook in cast iron.
Other than that, I don't suggest adding a multi without speaking with a medical professional. Going above some nutrients can be harmful.