Iodine is classified as a trace mineral and it certainly plays a very important role in thyroid function as well as the production of certain hormones which are needed in order to convert food into energy. Those who are on a diet will certainly want to consider eating more tuna on a regular basis because of the many different health benefits which it offers.
Seafood in general tends to be rich in iodine and you will be able to get it from things like shrimp, seaweed, and many different saltwater fish. It is important not to get too much iodine because doing so could mean a toxic reaction which lowers thyroid function.