Iron is a mineral with several important functions, the main function of which is to carry oxygen throughout the body as part of red blood cells. It is an essential nutrient, which means you need to get it from food. The Daily Value (DV) is 18 mg. Interestingly, the amount of iron your body absorbs depends in part on how much you store. Deficiencies can occur if your intake is too low to replace the amount you lose each day.