iodine
4 interactions related to iodine
cabbage + levothyroxine
Cabbage releases thiocyanates from glucosinolates that compete with iodide uptake at the thyroid sodium-iodide symporter. Case reports tie very heavy raw cabbage intake (1+ kg/day) to severe hypothyroidism, but typical cooked portions do not measurably affect levothyroxine requirements when iodine is adequate.
selenium + iodine
Iodine is the raw material for thyroid hormones T4 and T3, but selenium is required to build the deiodinase enzymes that convert inactive T4 into active T3 in peripheral tissues. Selenium also powers glutathione peroxidase, which protects thyroid follicular cells from the oxidative damage of iodine handling.
methimazole + iodine
Methimazole blocks new thyroid hormone synthesis but does not prevent the gland from using iodide already inside it. Adding a large iodine load (kelp, iodine drops, iodine-containing contrast, amiodarone) can fuel hormone production, blunt methimazole's effect, and in some cases precipitate worsening hyperthyroidism or thyroid storm.
cauliflower + levothyroxine
Cauliflower contains glucosinolates that can release thiocyanates competing with iodine uptake, theoretically increasing thyroid hormone demand. In practice, a comprehensive systematic review found brassica vegetables at normal dietary intakes do not impair thyroid function when iodine is adequate.