Thyroid Function Test Alterations Due to Supplements

Iodine Supplements

Standard prenatal supplement doses (150 mcg daily) are generally safe in iodine-sufficient populations, according to the American College of Obstetricians and Gynecologists 1
In iodine-deficient populations, supplementation programs (150-200 mcg/day) have been associated with increased incidence of iodine-induced hyperthyroidism, subclinical hypothyroidism, and thyroid autoimmunity, as reported by the Clinical Nutrition society 2
Chronic excess iodine exposure induces autoimmune thyroiditis and is associated with elevated TSH, lower thyroid hormone levels, and increased thyroid autoimmunity leading to hypothyroidism and goiter, as stated by the Clinical Nutrition society 2
Iodinated contrast agents used for radiologic studies, topical iodine disinfectants (povidone-iodine), and amiodarone (anti-arrhythmic medication) are common sources of excess iodine, according to the Clinical Nutrition society 2

In populations with high prevalence of thyroid disorders, iodine status should be assessed by 24-hour urinary excretion combined with thyroid function tests, as recommended by the Clinical Nutrition society 2