A. Iron is a nutrient which the body needs only in minute amounts. However, without the small amounts of iron our bodies contain, we would not be able to survive. Iron is necessary to build hemoglobin in the blood, which is responsible for carrying oxygen from your lungs to every cell in your body. Iron also helps our muscle cells store oxygen, aids the body in creating and using energy, and plays a role in the production of DNA. If we are iron deficient, we feel fatigued.

Iron deficiency is rare among men and postmenopausal women, and too much iron can cause iron overload (hemochromatosis). To play it safe, men and postmenopausal women should look for a multivitamin/mineral with no, or less than 10 mg, iron. In contrast, premenopausal women, and vegetarians who avoid all animal products, should look for 100% of the Daily Value (18 mg) of iron in a multivitamin.

This Q&A was written by Heather Jones, a registered dietitian, freelance writer, and nutrition professional based in Washington, D.C.