Iron. Historically, it has been thought that low thyroid
function may cause anemia. Recent studies suggest that low
thyroid function may be secondary to low iron status or
anemia. The reason for this is because TPO is a glycosylated
heme enzyme that is iron-dependent. The insertion of heme
iron into TPO is necessary for the enzyme to translocate to
the apical cell surface of thyrocytes (or thyroid epithelial
cells), thus assisting TPO to catalyze the two initial steps of
thyroid hormone synthesis (Zimmermann, 2006). A full
assessment of iron status could likely help to identify the
cause of many cases of thyroid malfunction