Iodine is a mineral that is a component of our thyroid hormones. If you have a look at the image of the molecular structure of a thyroid hormone you’ll see that several iodine atoms are needed (I) on each molecule (see image below). Deficiency can cause serious problems like goiter or cretinism. Iodine deficiency affects large numbers of people globally, especially in in-land populations where food sources are rare, and soil is iodine-depleted. Our bodies are unable to make iodine, so it is considered an essential nutrient that needs to be acquired through diet.
So if it’s so important, then why is there any controversy? It turns out that if you are one of the people suffering from Hashimoto’s, then taking iodine can be very problematic. Some practitioners will suggest that seaweeds or other foods with iodine should not be consumed. But this is where things get confusing, because for every practitioner who says you shouldn’t consume iodine there is another one who says you should.
Iodine can be the trigger for Hashimoto’s because it can reduce the activity of an enzyme called thyroid peroxidase (TPO). TPO is needed for thyroid hormone production (Source). Restricting iodine has been shown to be beneficial for Hashimoto’s (Source).
But what about those people who say iodine is beneficial for Hashimoto’s. They are right too!
Iodine + Selenium
Just looking at iodine doesn’t give us a complete picture of what is happening with Hashimoto’s. Selenium also has a significant role in thyroid health, and when it is deficient thyroid function can be impaired (Source). Selenium is needed to convert T4 to T3 (the active form of the hormone) and it also helps to regulate the immune response seen in Hashimoto’s (Source).
The combination of low selenium with high iodine is the problem. For people who have good selenium levels, iodine supplementation can be beneficial. For those who have deficient selenium, iodine can be problematic on its own.
It’s important to know your iodine and selenium levels if you are struggling with Hashimoto’s. Deficiency in these important nutrients could be a contributing factor to your condition. Or maybe you have high iodine levels, and supplementing with selenium is the missing puzzle piece.
If you have Hashimoto’s, it's important to be on a Paleo-AIP (autoimmune protocol) diet. Equally important is figuring out your iodine and selenium levels. Knowing these levels will help you determine if seaweeds and other iodine rich foods should or should not be part of your diet. The controversy is there for a reason, and you need to find out which route will benefit your health. I would suggest you go visit a naturopathic or functional doctor who can test both your iodine and selenium levels and develop a supplement protocol that is right for you.
Happy, Healthy Eating,