Iodine (Thyroid) — Frequently Asked Questions
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Frequently Asked Questions
Can too much iodine cause thyroid problems?
Can too much iodine cause thyroid problems?
Yes. Excess iodine intake (above 1,100mcg daily) can trigger both hypothyroidism (Wolff-Chaikoff effect) and hyperthyroidism (Jod-Basedow phenomenon), particularly in people with underlying thyroid conditions like Hashimoto's thyroiditis or Graves' disease. High-dose iodine protocols (e.g., 12.5-50mg daily) promoted by some practitioners lack safety evidence and can cause harm. Stick to the RDA of 150mcg unless directed otherwise by a physician.
Should I take iodine with selenium?
Should I take iodine with selenium?
There is evidence that selenium supports thyroid health by enabling the conversion of T4 to T3 and protecting thyroid tissue from oxidative damage. In iodine-deficient populations, selenium deficiency can worsen the effects of low iodine. Taking both together at appropriate doses (150mcg iodine, 100-200mcg selenium) is a reasonable approach for thyroid support, particularly if dietary intake of either mineral is low.
Do I need an iodine supplement if I use iodized salt?
Do I need an iodine supplement if I use iodized salt?
For most people using iodized salt regularly, additional supplementation is unnecessary. One-half teaspoon of iodized salt provides approximately 150mcg of iodine (the full RDA). However, if you use sea salt, Himalayan salt, or kosher salt (which are not iodized), avoid dairy and seafood, or follow a vegan diet, you may be at risk for insufficiency and could benefit from supplementation.