In this article, Debbie Whitaker states that certain vegetables contain a group of chemicals called goitrogens which may trigger hypothyroidism in certain people. These chemicals are partially deactivated by cooking the vegetable. These vegetables are "Broccoli, Brussels sprouts, cabbage, cauliflower, cassava root, horseradish, kale, millet, mustard, mustard greens, peaches, pears, radishes, rutabagas, soybeans, spinach, and turnips." Apparently raw peanuts are another culprit.
The author is not saying that eating raw vegetables will cause hypothyroidism. She's saying that if you have it or are at risk of having it, a specific diet can help.
I wonder if fermenting or pickling would deactivate the goitrogens in these foods? It seems that while 100% raw is wonderful for those who benefit from it, each person should customize their optimal diet according to their unique needs.