Carlson Labs - Kid's Chewable Iron Superior Absorption Natural Strawberry 15 mg. - 60 Tablets Iron is an essential mineral and an important component of hemoglobin, a substance in red blood cells that carries oxygen from our lungs to the rest of our body. Hemoglobin uses about two-thirds of our body's total iron. If we're lacking iron, our body can't produce enough red blood cells, which can affect our oxygen level and make us feel tired.