Iron, a trace mineral, supplies energy to every cell in the body. It is a key component of hemoglobin, the blood's oxygen-carrying pigment. Iron is also found in myoglobin, which supplies oxygen to muscles, and in compounds that keep the immune system strong. This mineral is critical to sharp mental functioning. Even slight deficiencies in iron can shorten attention span and make concentration difficult.
Normally, the body gets sufficient amounts of iron from the foods you eat. It manages to self-regulate itself, storing amounts you will need by automatically absorbing more iron when the need is high, and less when levels are adequate. Nonetheless, iron deficiency is still a significant public health problem. It can occur during periods of rapid growth--infancy, adolescence, and pregnancy--which increase the body's demand for this mineral. In addition, women who menstruate heavily tend to have lower iron levels.