Low Iron and Thyroid Dysfunction- is there a link ?
A growing body of evidence suggests that Iron Deficiency may play a significant role in the pathogenesis of thyroid dysfunction. Several studies have reported a high prevalence of ID in patients with thyroid diseases, particularly hypothyroidism and thyroid autoimmunity (TAI), which can impair the synthesis and function of thyroid hormones [6]. The production of thyroid hormones is negatively affected by ID, and their deficiency reduces the proliferation of erythrocyte precursors, both directly and through reduced secretion of erythropoietin by the kidneys [7,8]. Additionally, ID can affect the hypothalamic–pituitary–thyroid axis, leading to altered thyroid hormone levels and a decreased response to thyroid-stimulating hormone. Iron is also essential for the activity of thyroid peroxidase, an enzyme that catalyses the iodination of tyrosine residues in thyroglobulin, a precursor protein for thyroid hormone synthesis [9]. Correlation between ID and hypothyroidism is likely due to impaired thyroperoxidase (TPO) hemoprotein biosynthesis, as shown in a rat study in which ID reduced TPO activity [4]. Furthermore, animal studies have shown that ID can interfere with thyroxine deiodinase activity by reducing the conversion of thyroxine (T4) to triiodothyronine (T3) and with the regulation of thyroid metabolism at the central level [10,11]. Moreover, the interaction between thyroid hormones and iron is bidirectional since, through the TRα receptor, TH directly stimulates erythropoiesis [12,13].
•Clinical Manifestations
•Common symptoms of iron deficiency: fatigue, weakness, pale skin.
•Symptoms of hypothyroidism: weight gain, cold intolerance, depression, dry skin.
•Overlapping symptoms and the challenge of differential diagnosis.
Impact of Low Iron on Thyroid Function
•Reduced activity of thyroid peroxidase (TPO) due to iron deficiency.
•Decreased production of T3 and T4 hormones.
•Potential development of hypothyroidism (underactive thyroid).
(Thyroid UK, nd)
