If you are donating your own blood or if you have anemia, you may need extra iron. Your doctor may prescribe an iron supplement. Take it with vitamin C so it will be absorbed better. Some foods, medicines, and supplements can interfere with absorption of iron from the intestines. Eating foods that contain iron may also help you. Iron-rich foods include red meat, beans, nuts, and raisins. In some cases, you may need I.V. (intravenous) iron to help you prepare for surgery. Follow your doctor's specific instructions.