Iron absorption is affected by the iron status of the individual, the type of food eaten and vitamin C intake. Requirement Iron has many different roles in the body. About 65 to 75 percent of the body's iron is in the blood in the form of hemoglobin. Myoglobin, the compound that carries oxygen to the muscle cells, also requires iron. In addition, iron is involved in reactions within the body that produce energy.
Any excess iron is stored in the body as a reserve.
If iron is lacking in the diet, iron reserves in the body are used. Once this supply is depleted the formation of hemoglobin is affected. This means the red blood cells cannot carry oxygen needed by the cells. When this happens, iron deficiency occurs and anemia results. The greatest need for iron is during growth or periods of blood loss.