Every molecule of hemoglobin has four ions of iron in it. Hemoglobin is the compound in red blood cells that carries oxygen from the lungs to the tissues. Hemoglobin causes our blood to look red. A deficiency of iron in the diet results in fatigue, reduced resistance to disease, and increased heart and respiratory rate. A healthy adult needs about 18 mg of iron each day.
Dietary iron is found in large amounts in organ meats such as liver, kidney, and heart.
It is also present naturally in egg yolks, some vegetables, and shellfish. Vitamin C can increase the amount of iron absorbed into the body. Cereals are fortified with food grade iron filings as a food supplement. In the stomach the metallic iron is oxidized and eventually absorbed through the small intestine. If all of the iron from your body was extracted, you would have enough iron to make up only two small nails.