Effect of Iron Deficiency on the Increased Blood Divalent Metal Concentrations

The apical divalent metal transporter 1 (DMT1) and the iron exporter ferroportin 1 (FPN1) are responsible for the absorption of iron and other divalent metals (manganese, lead, and cadmium). Thus, an iron-deficient diet can lead to excess absorption of manganese, lead, and cadmium, and high blood concentrations of these metals. Relative to males, females of childbearing age have higher blood concentrations of manganese because of their lower blood concentrations of ferritin. Moreover, relative to premenopausal women, menopausal women have lower blood manganese levels because their higher concentrations of ferritin. There is also a significant increase in the whole blood manganese level throughout pregnancy due to the upregulation of iron absorption at this time. Several previous studies reported a temporal relationship between iron deficiency and increased blood lead concentrations in children. However, this association does not occur in postmenarcheal or postmenopausal women because estrogen promotes bone mineralization and redistributes blood lead into the bone, overshadowing the effect of ferritin on blood lead level. Although blood cadmium concentrations are higher in females of childbearing age because of their lower ferritin concentrations, there is no association of blood cadmium and iron levels in infants and postmenopausal women.