Is Iodine Deficiency The Conscientious Gourmand's Disease?

Me shoveling seaweed in Scotland on the Isle of Mull, where it is used as a soil fertilizer and conditioner

Three months ago I got an alarming test result: my TSH (thyroid stimulating hormone) was 5.36, which is a marker for hypothroidism. I looked through past medical records and it had been about 3 the year before and a little above 1 in 2010. My other thyroid markers were normal and I had no anti-thyroid antibodies, so my doctor told me we should wait and see and then re-test. I mentioned that I didn't use iodized salt and she said it might be worth trying adding that back in.

The problem is that I don't salt my food that much when I cook at home. I also like gourmet salt, which has varying levels of iodine. Since moving to Chicago, which is not exactly the seafood capital of the world, and being more aware of safety and environmental issues with seafood, I don't consume a ton of seafood. I like seaweed, but I'm not that consistant with eating it. I also eat at restaurants quite a bit and while restaurant food has a ton of salt, chefs often use sea salt at the higher end places I eat at. 

Seaweed can aggrevate thyroid issues if you have autoimmune thyroid disease (which anti-thryoid antibodies indicate), so I wouldn't have taken it if my other numbers had been off, but because they weren't, I did take kelp and selenium supplements for two months and then I re-tested and it was 2.22. Still not ideal, but better than 5.36. It could have been a blip, but the fact it had an upward trend over time indicated to me that it possibly was tracking with diet. 

Few doctors will consider iodine. To them, it's just not on the radar and they won't test for deficiency. Most of their patients probably don't use weird expensive salt, but as people eat out more and more and eat more processed foods (which almost never contain iodized salt), it's likely to become a problem for everyone. The American Academy of Pediatrics has warned that one-third of pregnant women in the United States are iodine-deficient.

I'll keep tracking and see where my TSH goes, but I'm probably going to have to keep supplementing given my paltry seafood intake and penchant for gourmet salts. Visiting Scotland, it was clear to me that my ancestors enjoyed a life full of seafood and seaweed (we used it for fertilizing the fields and people used to eat it more there), which is just not something I have in Chicago. Milk, meat, and eggs may contain iodine, but the amount varies and considering a. I eat mainly local products b. I live in a geographical area once known as the goiter belt c. dairying practices now use less iodine, I don't think these are a reliable source for me.