Thiocyanates are found in all cruciferous vegetables, not just kale, and rutabaga is the vegetable with the most. Runners-upâalongside kaleâare turnips, cabbage and Brussels sprouts, but the rest of the cruciferous family has very little. If youâre still worried, ask your doctor to check your thyroid. Itâs a simple blood test. If youâre taking thyroid hormone for an underactive thyroid or have a predisposition to thyroid problems, you are more susceptible to the effects of thiocyanates. Donât banish kale.