Iodine deficiency is primarily caused by goitrogens like sulforaphane and other isothiocyanates that compete with iodine at the ionic level in the thyroid.

“One of the things that I see that many people do not talk about when it comes to iodine and thyroid is there's compounds known as goitrogens. And these goitrogens are neither good nor evil, but they're actually kind of a nice check and balance. You need more iodine if you consume more goitrogens. And some examples of these are some of my favorite foods-- cruciferous vegetables. Boron is also a goitrogen.”

“these are Melanesian women a high is the high consumption of cruciferous vegetables among Melanesian women a group of maya iodine deficiency may contribute making it may explain the exceptionally high incidence of thyroid cancer in this group so this is fascinating that in this Melanesian population they are concerned about goitrogenic foods these are cruciferous vegetables that have isothiocyanates like so for a fame which compete with iodine and level the thyroid and they this may be a correlation between higher rates of thyroid cancer”

“my concern is that consumption of goitrogenic vegetables broccoli cauliflower turn-up collard greens is going to lead risk of hypothyroidism because these thiocyanate these isothiocyanates and Goran compete with iodine at the level of the thyroid”

“iodine deficiency is the result of goitrogens it's the result of compounds like sulforaphane and other isothiocyanates that are going to steal iodine or compete with ionic level thyroid”

“unless they were doing something that significantly inhibited their iodine absorption and uptake at the level of the thyroid like tons of broccoli because we know that the isothiocyanates in that whole family kale Collard cabbage charred Etc the entire Brasa family those are going to inhibit the absortion of iodine level of thyroid that's one of their main mechanisms of toxicity”

“Grogenic substances, such as isothiocyanates. These occur in the brassica family, the mustard family. So kale, cauliflower, cabbage, all these foods, Brussels sprouts, soy is high”