What it does
The thyroid incorporates iodine into its hormones. Requirements rise during pregnancy and lactation because iodine supports fetal and infant development. Deficiency and excess can both disrupt thyroid function.
Food sources and absorption
Iodized salt, seafood, dairy products, eggs, and some fortified foods can contribute. Specialty salts are not automatically iodized. Seaweed content varies widely, so it is an unreliable way to dose iodine precisely.
Safety and individual context
People with thyroid disease, those avoiding dairy and seafood, pregnant people, and anyone considering kelp or high-dose iodine supplements should seek individualized advice. More is not safer.
Primary reference
NIH Office of Dietary Supplements consumer fact sheet
How to use this information
Reference values describe population needs and are not a diagnosis. Food patterns, health conditions, pregnancy, laboratory results, and medications can change what is appropriate. Avoid high-dose supplementation unless there is a clear reason and qualified guidance.