Raw Kale Can Cause Thyroid Dysfunction: Yes but only in large quantities raw in salads.
Raw kale has goiter causes substances that can cause thyroid dysfunction but only in larger quantities.Cooked kale is safe. Raw Kale contains progoitrin, a compound that can interfere with thyroid hormone synthesis, as well as thiocyanate ions, which can overwhelm the iodine uptake.
Cabbage related thyroid disease
88-year-old woman in China fell into a coma in 2010 after a case of cabbage-related thyroid dysfunction. In an attempt to avoid diabetes, she had been eating 3 pounds of raw bok choy every day for months. So, the good news seems to be that moderation is best in all things, including kale.