Relationship between iodine and thyroid diseases br Many of the diseases of the thyroid gland are associated with iodine, more precisely with its deficiency or its excess. br This trace element is actively involved in important biochemical processes of the thyroid gland. With endemic goiter and thyrotoxicosis, nutrition with the required amount of iodine is a very important measure, but with thyroiditis, foods high in iodine should be limited.