Iron is an important component of hemoglobin, which consists of red blood cells (erythrocytes). Hemoglobin contains about two thirds of the iron in the body. It combines with oxygen, and red blood cells carry it from the lungs throughout the body. This mineral is also included in many elements responsible for cholesterol metabolism, the conversion of calories into energy, and the fight against toxins. Thanks to iron, the immune system copes better with its functions, and red blood cells use it to send carbon dioxide to the lungs for processing. It is also essential for maintaining healthy cells, skin, hair, and nails.