Iodine is usually involved in goiters, but the problem is, it can be due to too much Iodine or due to too little. You have to check the diet to be sure which it is.
If the diet is full of salt that has been supplemented with Iodine (iodized salt) and shellfish, fish, organ meats, seaweed, kelp, kombu, then you have been getting too much iodine and need to back off.
If your diet is completely lacking these things, you need more iodine.