Why High Iodine Foods Aren’t Always the Best for a Healthy Thyroid Diet

Why High Iodine Isn't A Good Idea if you have hyperthyroidism or an autoimmune thyroid disease like Graves Disease or Hashimotos and want a healthy thyroid diet.

Hello lovelies:

I have a confession – I LOVE seaweed. Like eat 3 packages in one sitting before I realize what I’ve done love seaweed! This time last year, seaweed was a go to snack… I may have cleaned out a few store shelves throughout the summer. I couldn’t get enough… but seaweed and I have since parted ways. While I miss it, I know that our breakup was for the best. Why? Because, while there is no such thing as a perfect thyroid diet, excess iodine is not a good idea.

When it comes to iodine heavy foods, Graves Disease, Hashimotos and Hyperthyroidism do not respond well.

If you have one of these illnesses and/or enjoy iodine heavy foods like seaweed or spirulina, you have to read this:

Why High Iodine Isn't A Good Idea if you have hyperthyroidism or an autoimmune thyroid disease like Graves Disease or Hashimotos and want a healthy thyroid diet.

 What does iodine have to do with thyroid health?

Iodine plays a fantastical role in thyroid function. It’s a key component in thyroid hormone production, and those little hormones dictate the speed of every cell in your body… needless to say, they’re pretty darn important. Balance is key, as too little or too much iodine can affect thyroid function (even if you don’t have a disease).

But deficiency is far more common than you might think! In the early 1920s people were so prominently iodine deficient that parts of Canada and the United States became known as the “Goiter Belt” – People were becoming hypothyroid and developing goiters at a distressing rate. At the time the best response was to iodize table salt… and since many of us LOVE salt, the problem was practically eliminated in North America. This was a step in creating a healthy thyroid diet; it made a huge difference.

However, according to the American Thyroid Association, Iodine Deficiency continues to be a global problem, with approximately 40% of the world’s population at risk.

Iodized salt shouldn’t be your only source of dietary iodine (we shouldn’t be overloading on salt, after all). And if you have non-autoimmune hypothyroidism or an iodine deficiency a little extra nutritional support for your thyroid is a wonderful thing. So where do you get it?

Here are some awesome dietary sources of iodine:

  • Eggs
  • Beans (Pinto, Navy, Black-Eyed, Lima, Kidney)
  • Green Peas
  • Corn
  • Rice
  • Oats
  • Meat (Turkey, Beef, Chicken, Pork)
  • Fish (Cod, Haddock, Tuna)
  • Spirulina and Chlorella
  • Seafood (especially seaweed)

Seaweed, spirulina and chlorella take the cake in the Iodine front.

The average adult needs approximately 150 micrograms of iodine per day. Seaweed, however, can contain up to 2984 micrograms of iodine per sheet! That’s up to 1,989% of your daily recommended intake (source)! And a serving of spirulina can have up to 4500 micrograms Talk about iodine overload!

Too much iodine isn’t great for anyone. It’s been linked to hyperthyroidism and even thyroid cancer.

“The number of reported cases of thyroid cancer, particularly papillary thyroid cancer, has also increased following iodine supplementation in some studies, including a nearly 20-year study in northeastern China and a >50-year study in Denmark.” (Consequences of Excess Iodine, Angela M. Leung and Lewis E. Braverman [source])

However, if you don’t have an autoimmune thyroid disease, hyperthyroidism or another medical reason to avoid eating high levels of iodine, you can still have a healthy thyroid diet and occasionally enjoy high iodine foods.

There’s even a way to help keep things balances. Add goitrogens to the mix when you enjoy high iodine foods (like kale, broccoli, cauliflower, spinach. Find out how goitrogenic foods play a role in a healthy thyroid diet here).

Just remember, there is such a thing as too much of a good thing; balance is key. Overwhelming your system with an overabundance of iodine can affect anyone’s thyroid health.

But why avoid it if you have Hyperthyroidism, Graves Disease or Hashimotos?

Iodine is a key component in diagnosing Graves Disease.

In fact, a Radioactive Iodine Uptake test is part of how Graves Disease is diagnosed. Graves Disease causes that thyroid to suck up iodine like candy! That’s also why Radioactive Iodine is often used to destroy the gland if remission can’t be achieved. Your poor gland can’t say no to iodine, but the radiation takes it down from the inside. Think of it as a thyroid hating SWAT team.

Even if you’re in remission an overabundance of iodine is still not desirable.

“Euthyroid patients previously treated with antithyroid drugs for Graves’ disease are prone to develop iodine-induced hyperthyroidism” (Iodine Excess and Hyperthyroidism, Roti E, Uberti ED. US National Library of Medicine, National Institutes of Health – source). That doesn’t mean that you avoid iodine like the plague; I’m certainly not planning on giving up eggs (which have 24 micrograms of Iodine per egg).

But overloading is not an option if you want a healthy thyroid diet – and it’s impossible to eat seaweed without doing just that.

If you’re currently Hyperthyroid (even if you don’t have an autoimmune disease)

Excess iodine intake can reduce the effectiveness of your anti-thyroid medication (source). And euthyroid individuals who battled non-autoimmune hyperthyroidism in the past may be more likely to experience a relapse if iodine is consumed in excess.

It’s also important to note that excess iodine can potentially interact with some medications for high blood pressure and Potassium-sparing diuretics (source) – talk to your doctor if you’re on one of these medications and are concerned about iodine intake.

What about Hashimotos?

You would think that Hashimotos, Graves Disease’s autoimmune hypothyroid cousin, would be the opposite. Especially since non-autoimmune hypothyroidism can be caused by iodine deficiency.

But unfortunately that isn’t necessarily the case. Autoimmune thyroid diseases (Graves and Hashi’s alike) are more prominent in areas with excess iodine intake (source). Some studies have shown that iodine could potentially effect thyroid auto-antibody production and definitely influences the production of thyroid hormones.

Even small amounts (250 micrograms per day, 100 micrograms more than the daily recommended intake) had an effect on Hashimotos patients in this study (Effects of small doses of iodine on thyroid function in patients with Hashimoto’s thyroiditis residing in an area of mild iodine deficiency, Reinhardt W, Luster M, Rudorff KH, Heckmann C, Petrasch S, Lederbogen S, Haase R, Saller B, Reiners C, Reinwein D, Mann K. US National Library of Medicine, National Institutes of Health).

Want to learn more about what foods affects your thyroid health? Click here for to learn what foods make for a healthy thyroid diet.

As a Graves Disease Warrior happily living in remission, I broke up with seaweed and I try to keep my iodine consumption under wraps. This is a key component in creating a healthy thyroid diet and thriving with Graves. My fellow Autoimmune Thyroid Disease and hyperthyroid fighters may want to follow my lead.

I won’t lie, I’m a little envious of those who can enjoy delicious seaweed snacks…

Please remember that while changing your diet will do wonders for your wellbeing and help your body function as optimally as possible… But it is in no way a replacement for medical treatment!

Continue to work with your doctor and receive regular checkups and testing.

Health and love,


Thought of the day: Good for you does not necessarily mean good for me.

Have you had to break up with a favourite food for the sake of your health? Let me know in the comments below.


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Want to learn more about iodine and thyroid health? Here’s some links to explore.












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