Micronutrient Supplementation for Hypothyroidism Management

Introduction to Micronutrient Supplementation

The American Thyroid Association recommends increasing iodine, selenium, and iron intake to help manage hypothyroidism only when specific deficiencies of these micronutrients are documented, not as a general therapeutic strategy for all hypothyroid patients 1, 2

Iodine supplementation is beneficial only in iodine-deficient hypothyroidism and can be harmful in iodine-sufficient populations 1, 2
The recommended daily iodine intake is 150 mcg/day for adults, with requirements increasing to 220 mcg/day in pregnancy and 290 mcg/day during breastfeeding 2, 3
Assess iodine status through 24-hour urinary iodine excretion (normal: 100-300 mcg/24hr), not serum TSH, as TSH remains normal despite frank iodine deficiency 1, 3

Selenium supplementation (50-200 mcg/day) reduces thyroid peroxidase antibodies and may improve thyroid function in selenium-deficient patients with autoimmune thyroiditis 1
Healthy thyroid function depends on adequate selenium provision at any age, as Type 1 5'-deiodinase (which converts T4 to active T3 in the liver) is a selenoenzyme 1, 2, 4
Daily selenium requirements for patients receiving enteral nutrition are 50-150 mcg, with higher requirements (150-200 mcg) in parenteral nutrition patients with increased losses 5

Iron deficiency impairs thyroid hormone metabolism and should be corrected in hypothyroid patients, particularly menstruating women 1, 2
Daily iron requirements for enteral nutrition are 18-30 mg, with standard parenteral nutrition providing only 1 mg/day (insufficient for deficiency correction) 5

Assess baseline status before supplementation: 24-hour urinary iodine, serum selenium (if available), serum ferritin, and complete thyroid function tests (TSH, free T4, free T3) 1, 3
Monitor for non-dietary iodine sources including iodinated contrast agents, povidone-iodine disinfectants, and amiodarone, which can deliver massive iodine loads 3