Sadly, the feds banned most iodine products from pharmacies because it can be used as a stage in meth production. You can't easily even buy iodine crystals for chem labs without serious paperwork. The old days of making nitrogen triiodide for fun contact explosives are gone too. It's that neat stuff so unstable that if you touch it, it blows up. A little goes a long way.

Table salt however is available containing enough iodine to be of nutrient use.