Dietary iron has three forms: inorganic, heme, and ferritin. About 25 percent of the iron in the body is stored as ferritin, found in cells and circulates in the blood. The average adult male has about 1,000 mg of stored iron (enough for about three years), whereas women on average have only about 300 mg (enough for about six months).
The red blood cell pool is the largest functional iron compartment in the body. Its requirements therefore have a dominant influence on studies of iron transport and storage.
The body requires iron for the synthesis of its oxygen transport proteins, in particular hemoglobin and myoglobin, and for the formation of heme enzymes and other iron-containing enzymes involved in electron transfer and oxidation-reductions.
Hemoglobin is a large molecule made up of proteins and iron. It consists of four folded chains of a protein called globin, designated alpha 1 and 2, and beta 1 and 2 (Figure 3a). Each of these globin molecules is bound to a red pigment molecule called heme, which contains an ion of iron (Fe2+)
Almost two-thirds of the body iron is found in the hemoglobin present in circulating erythrocytes, 25% is contained in a readily mobilizable iron store, and the remaining 15% is bound to myoglobin in muscle tissue and in a variety of enzymes involved in the oxidative metabolism and many other cell functions.
The best source of iron is animal-based foods, especially red meat and offal (such as liver). Chicken, duck, pork, turkey, eggs and fish also have iron. Iron is also found in many plant-based foods such as: green vegetables, for example spinach, silverbeet and broccoli.
Iron for
blood circulation
