Iodine is considered a trace mineral. Today we have lots of iodine deficient individuals due to not having iodized salt. Many individuals take pink salt which lacks iodine.
Iodine major use is for the thyroid gland but also for proper immune system function. It has anti cancer effects, it is a potent antioxidant and and modulated estrogen response on breast cancer cells
Iodine protects the cell and DNA damage. Japanese women have been shown that they have the lowest incidence of breast cancer. as they consume 25 x higher iodine consumption In studies with as low as 5 mg of iodine have shown increased cell apoptosis, decreased proliferation and decrease in the estrogenic effects on cells.
So you should take iodine especially if you have breast cancer or know someone who does. You need to consult your health care practitioner about the exact amount as it is individualized