Functions: The primary function of iron in the body is the formation of hemoglobin. Iron is the central core of the hemoglobin molecule, which is the essential oxygen-carrying component of the red blood cell (RBC). In combination with protein, iron is carried in the blood to the bone marrow, where, with the help of copper, it forms hemoglobin. The ferritin and transferrin proteins actually hold and transport the iron. Hemoglobin carries the oxygen molecules throughout the body. Red blood cells pick up oxygen from the lungs and distribute it to the rest of the tissues, all of which need oxygen to survive. Iron's ability to change back and forth between its ferrous and ferric forms allows it to hold and release oxygen. Each hemoglobin molecule can carry four oxygen molecules. This large protein molecule makes up approximately 30 percent of the RBCs. Amazingly, there are some 20 trillion RBCs in the average human body (men have more than women), and about 115 million red blood cells are made every minute. As mentioned before, approximately 90 percent of the iron needed to make those cells comes from recycled RBCs that are normally destroyed by the spleen at the end of their 120-day life span.

Myoglobin is similar to hemoglobin in that it is an iron-protein compound that holds oxygen and carries it into the muscles, mainly the skeletal muscles and the heart. It provides our ability to work by increasing oxygen to our muscles with increased activity. Myoglobin also acts as an oxygen reservoir in the muscle cells. So muscle performance actually depends on this function of iron, besides the basic oxygenation by hemoglobin through normal blood circulation.