Goitrogens compete with iodine - Flax seeds
The Crucifers family Brussels sprouts, cabbage, kale... compete too
Steaming reduces goitrogens 1/3, boiling 90%
Fermenting sauerkraut activates the goitrogens
Rosaceae family cherries, almonds, peaches, apricots, strawberries... are also goitrogenic
Lima beans too
"You know, eat these foods in moderation, and make sure that you compensate for their inclusion in the diet with eating more seafood, perhaps some occasional seaweed..."
Chris Masterjohn PhD in Nutrition