5 Foods that Can Wreck Your Thyroid

I have had thyroid issues on and off throughout my life and have heard that foods can affect your thyroid health. These 5 Foods Could Be affecting thyroid disease.  Are you eating any of them?  What do you think of this list--do you think it's accurate or should anything be taken off or added? I wonder if they would have the same effect on someone with hypothyroidism as with hyperthyroidism.


{Hypothyroidism. It’s a big topic these days. Seems almost everyone has thyroid problems and adrenal fatigue these days .  In fact, I’ll be writing about my own thyroid issues soon, hopefully, and will share some of what I’ve learned. Today, let’s learn about 5 Foods that might be a problem for hypothyroidism.  Are YOU eating these?}

So, you’ve recently found out that you have hypothyroidism.

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What you eat can impact your thyroid function—for better or worse.

Your doctor probably won’t tell you about this, but knowing how the foods you put in your body impact your thyroid function is just as important as getting the right tests and getting on the proper dosage of thyroid medication.

5 Foods to Avoid if You Have Hypothyroidism

1. Soy

Soy is everywhere. Soy burgers, soy cheese, soy milk. It isn’t the health food it’s been made out to be, however.

The problematic compound in soy (for your thyroid) are the isoflavones. In fact, a study in the Journal of Clinical Endocrinology and Metabolism reported that researchers fed some subjects 16 mg of soy isoflavones, which is the amount found in the typical vegetarian’s diet,  and others 2 mg soy isoflavones, which is the amount found in most omnivore’s diets. The subjects fed 16 mg were 3 times more likely to cause patients to convert from subclinical hypothyroidism to overt clinical hypothyroidism (Sathyaplan, 2011).

Cooking does not destroy soy isoflavones. Eliminate soy as much as you are able from your diet. 

What about soy formula?

Soy is not a friend of babies. Check out what the researchers in this study found:

Infants fed soy formula are at higher risk for hypothyroidism and for later development of autoimmune thyroid diseases. In humans, goiter has been detected in infants fed soy formula; this is usually reversed by changing to cow milk or iodine-supplemented diets . After the 1960s, manufacturers reportedly began adding iodine to formulas to mitigate thyroid effects.” (Doerge, 2002)

Soy formula should not be your go-to option if you are having difficulties breastfeeding. Watch out, because even formula that isn’t labeled “soy formula” can contain soy. If you are having trouble breastfeeding, be sure to check out these natural ways to increase your breast milk or try some of these lactogenic herbs.

Finding donor milk is also a far superior option to formula as is making your own cow’s milk formula or goat’s milk formula. .

2. Gluten

If you have a thyroid problem and you’re eating wheat or other forms of gluten, you need to stop. Now.

Nearly 90% thyroid disorders are autoimmune in nature (that means that about 90% of all hypothyroid patients have an autoimmune disease).

There is a strong connection between gluten-intolerance and autoimmune thyroiditis. There are even some doctors who are prescribing a gluten-free diet for all of their patients with thyroid disorders. Check out this post to find out more about the thyroid-gluten connection..

3. Cruciferous Vegetables

Broccoli, cauliflower, cabbage, kale, brussels sprouts, radishes, turnips, collard greens… and the list goes on (You can find the complete list of cruciferous vegetables here). Some of my favorite veggies are in this list. But these vegetables can indeed cause problems with your thyroid.

These vegetables are considered to be goitrogenic foods. That is, these are foods that cause an enlargement or goiter of your thyroid. They also slow down the function of the thyroid by making it difficult for your body to use iodine, a necessary building block of thyroid hormones.

Good News: Cooking Helps

Does this mean you need to completely give up some of your favorite vegetables? NO! Yay.

Finally some good news, right :)?

In fact, many of the enzymes in cruciferous vegetables can be partially destroyed by heating foods. So, if you’re going to eat cauliflower, cabbage, or kale – be sure to cook the vegetables before eating them.


4. Fluoridated Water

Until the 1950s, fluoride was prescribed to those suffering from hyperthyroidism as a thyroid inhibitor… and it worked in surprisingly low doses. This may sound strange, but fluoride exacerbates the impact of iodine deficiency. As was discussed earlier, iodine is essential for the body in order to create thyroid hormones (Gas’kov 2005Hong 2001Wang 2001Zhao 1998Xu, 1994).

The National Research Council, put together a 500-page review of fluoride and toxicology. Here’s what they had to say about fluoride’s impact on thyroid disease:

“The effects of fluoride on various aspects of endocrine function should be examined, particularly with respect to a possible role in the development of several diseases or mental states in the United States. Major areas of investigation include . . . thyroid disease (especially in light of decreasing iodine intake by the U.S. population).” (National Research Council, 2006)

There are other studies that are somewhat mixed, but if you’re not avoiding fluoride because of goiterigenic properties there are plenty of other reasons to try to eliminate fluoride from your diet.

How to Get Rid of Fluoride?

• Stop drinking fluoridated water. Check out this comparison of different filtration options: they range from very pricy to very affordable. (Surprisingly, the price is not always indicative of the quality of the filtration system.)

• Stop using fluoridated toothpaste and mouthwash. You can find a number of healthy toothpaste’s you can purchase or recipes to make your own!

• Don’t forget to check your medications. You might be surprised to learn that many common medications are fluorinated. Antidepressants, antacids, arthritis medications, and more contain fluoride. Be sure to check this site to find out if the medication you’re taking is on the list.

  • (Note from Adrienne:  I use a Berkey filter to get fluoride out of our family’s water.  I am a dealer and would be happy to help you with getting one of these at a great price.)

5. Processed Foods and Foods Containing Sugar

Sugar and processed foods cause inflammation in the body. Inflammation inhibits T4 to T3 conversion.

Moral of the story: decrease foods that cause inflammation.

Eat plenty of fruits, veggies, free-range eggsgrass-fed meats, and healthy fats.

(Hint: inflammation is just another reason to avoid wheat and other grains.)

For more thyroid information, see the following:

– Why Your Thyroid Test is Wrong-And What to Do About It

– Got Hypothyroidism? 5 Questions You NEED to Ask Your Doctor

Could THIS Be the Cause of Your Thyroid Disease?

Please note  – many of the links in this post are affiliate or referral links. If you click on them and make a purchase, I might make a commission. Your support is oh so appreciated, and it helps keep this free resource up and running – thanks!

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I so wish I had had this resource when I first got sick.

The following book is a fabulous resource for those with thyroid issues.  Did you know that it’s estimated that 90% or more of those with hypothyroidism have Autoimmune Hashimoto’s?

I devoured this book totally in just a few sittings after getting it.  It’s so full of great information and it’s one of those “keeper” books.

Other books I take out of the library, but “keeper” books are for buying and taking notes in and going back to over and over again.

I met the author this year and she knows what she is talking about.

One of the best books on thyroid health in my opinion.

One of the best books on thyroid health in my opinion.

Please remember: neither Adrienne nor I are doctors, so please do not make changes to your diet, supplements, or exercise program without first consulting with your physician.

So what do you think?
Did you know that all of these foods are problematic for good thyroid health?

Luke-Trisha-150x150Trisha Gilkerson is a homeschooling mom to four crazy boys. She blogs with her awesome hubby Luke at Intoxicated on Life where they talk about faith, homeschooling, and health. They’ve authored the Write Through the Bible curriculum and family Bible Studies and have recently released their first healthy living book – Weeding Out Wheat: A Simple Faith Based Guide. They love connecting with their readers, so be sure to follow them on their blogFacebookTwitterGoogle+, and Pinterest.


    Speak Your Mind


  1. I don’t agree with your claim that the healthiest vegetables interfere with thyroid function. I could not find any real evidence that supports your claim. My Dr also disagrees about this claim as well. were is the actual research and by whom was it done by.

    • Hi Tracy,
      I wanted to make sure you noticed that the recommendation in this post wasn’t to completely eliminate these vegetables, but to make sure that most of the time when you’re eating them to cook them and not eat them raw. In fact, I have hypothyroidism, and I very frequently eat these vegetables cooked and very occasionally will eat them raw. Of course, I don’t think they are one of the worst offenders on the list, but it’s good to be aware that they can contribute to problems if you eat them in great quantities raw.

      Below, I’m listing just a few journal articles that you can check out for further reading on this topic:
      Impact of flavonoids on thyroid function. Food and Chemical Toxicology, Volume 49, Issue 10, October 2011
      Chandra AK et al. Goitrogenic content of Indian cyanogenic plant foods and their in vitro anti-thyroidal activity. Indian J Med Res 2004; 119(5): 180-5.
      Ferreira AC et al. Inhibition of thyroid type 1 deiodinase activity by flavonoids. Food Chem Toxicol 2002; 40(7): 913-917.
      Oregon State University’s Site on Micronutrients: http://lpi.oregonstate.edu/infocenter/foods/cruciferous/

      • This is only harmful if you have iodine deficient thyroidism…which is rare. Eat your kale and enjoy.

        • I personally think that most people are deficient in iodine, do you not think so? I am doing more reading on cruciferous veggies so hope to have more information soon.

  2. I’m curious as to whether fermented soy products like tempe, miso, and soy sauce cause these same issues. Have you seen any research on this?

    • The Weston A Price Foundation has literature on this. Correct me if I am wrong but I believe that they are saying that a small amount of soy foods such as soy sauce, miso, natto, tofu, etc. as long as they are made in the traditional manner (use them as a guide for this) used in small quantities such as a condiment are fine. They say that this is the way that they are used in traditional Asian diets anyway. Things like soy milk, edammes, textured vegetable protein would have a thyroid antagonizing and hormone disrupting effect. I know from personal experience that about 2 months a breakfast drink that had soy protein in it had may hair falling out and a benign growth developing. My brother drinking the same drink for a few months had a benign growth on his finger removed. In my personal case adding a daily 10,000 iu of Vitamin A (not beta-carotene) to my already established D3 and K2 regime suddenly allowed me to stop taking my 100mcg of T4.

  3. Thank you for this informative article. I do eat cruciferous vegetables but cook them after seeing this information before. Unfortunately I had to give up cole slaw, which I love. The past several years I have been making sauerkraut and am wondering what your opinion is on eating raw cabbage that has been fermented and it’s effect on the thyroid. Thanks!

  4. My mom gave me soy formula – she was told her milk “wasn’t good” so she couldn’t nurse me……..I was the oldest of 5 kids and I find it interesting that she was able to nurse all of the others after me. Hmmm….. I have had allergies and other issues that we have wondered if they could have been impacted by all of the soy I ingested as a baby and now, in our family, we avoid it for all of us. Thank you for posting this.

    • I can say that breastfeeding is HUGE for gut health. I hope to write more about that soon. I am so sorry to hear. I was barely nursed as well and have suffered for it.

  5. Maria Aguilera says:

    Hi, I am interested to do a comparison on all the water filtration systems, specifically to remove as much of fluoride, chemicals, pesticides, heavy metals and all destructive modern day contaminants found in water, but your link takes me to a website under construction. Please provide a better link as I want to purchase the best water filtration system.
    Thank you,
    Maria Aguilera

    • Hi Maria,

      I apologize for the inconvenience, we were undergoing some changes on our site that is why you received the notice when you got there. The site is now back up and you should be able to check out the post on various water filtration methods.

  6. Thanks for this list! Does the breaking down of enzymes in lactofermentation make a difference for cruciferous vegetables? Also, does souring or soaking wheat/spelt/kamut/rye/any other gluten-containing grains in forgetting make any difference in the connection to inflammation?

  7. Nathalie says:

    Hi Trisha. I think of the 5 foods you’ve listed to avoid, I would put processed foods and man-made sweeteners (like HFCS and aspartame) at the top of the list. Not only for those with hypothyroidism, but really anyone. Soy would probably be 2nd on my list, unless it was being used as a condiment (like soy sauce, for example) if it were brewed or fermented in a traditional method. Fluoridated water is definitely next as there is no way to ensure that you’re getting what is considered an “optimal dose” by pro-fluoridationists, and not getting too much. So even if you believe in fluoride (which personally I do not) you could easily be going way over what is considered safe (by the pro-fluoride groups). And again, I think that all 3 of these: processed foods (and man-made sugar), soy (except as a condiment), and fluoride should be avoided as much as possible by anyone. But that’s just my opinion. Good article, Trisha.

  8. I have hyperthyroidism, which is seldom discussed… Do you suppose that if I eat these foods it might actually help to suppress my thyroid?

    • Yes, unfortunately “hyperT” is rarely discussed…I have Graves’ disease and have spent the better part of 3 years fighting western medical practices and researching how to address my autoimmune disease. And yes, eating high levels of cruciferous veggies could have a mild helpful suppressing effect for iodine uptake….though there is much speculation on the validity of them causing issues “hypoT”. There is much research showing the anti-inflammatory effects of these veggies greatly outweigh any minor suppressing effectshttp://www.drfuhrman.com/library/cruciferous_vegetables_and_thyroid.aspx. This author gives good basic highlights of certain elements that can aggrevate thyroid (either side of thyroid issues)….it is actually much more complex and anyone with thyroid issues…should take great care to eat clean, unprocessed, non GMO foods..as well as look at vitamin, mineral deficiencies, gut flora and digestive enzyme balance.
      Lastly, (if you haven’t already found her)…..Elaine Moore’s website is invaluable for hyperthyroid issues.

  9. My Slavic grandmother and her family practically lived on cabbage and never had thyroid problems.

  10. What if you don’t have a thyroid? I had mine completely taken out 8 years ago this month… my dr says im on enough thyroid replacement to handle veggies such as cale, broccoli, etc. raw. Is this not true? I LOVE raw veggies and juice kale daily. (I also love radishes and eat them like candy, daily… had NO idea they are bad for us!) Ugh. Anyway, can you help me figure out if I shouldnt eat these things even without a thyroid in my body please? I am so lost on this topic. Thank you.

    • That’s a very good question. I don’t know. I will see if Trisha can come and chime in. I did just read on one site that you don’t need to be particularly concerned about this if your thyroid has been removed.

    • Hi Wendy,

      Since you don’t have a thyroid, I think you can enjoy all of those raw veggies in abundance. :) You don’t have to worry about those veggies slowing down your thyroid function, since you don’t have one. :)

  11. Wow, cruciferous vegetables! I did not know this! Thanks for the education!

  12. So frustrating…all anyone ever talks about is hypothyroidism and Hashimoto’s while it is virtually impossible to find anything on hyperthroidism and Graves’ disease. Also frustrating, is how often information on diets for thyroid disease contradict themselves. I don’t know whether I’m coming or going with all the information out there.

    • It is hard. However from the limited research I’ve done the dietary lists seem similar. I think so many people don’t know what they are doing w/ thyroid disease. Looking into Th1 and Th2 is crucial too I think.

  13. booooo on the cruciferous vegetables I so ? them. No more raw kale salads (having toddler like meltdown). I understand cooking helps, what about fermented? I love me some sauerkraut, kimchi and horseradish? Do you know if the fermentation process makes the veggies less taxing on the body?

    • I am reading mixed things on this. Some say that if you have iodine rich foods you can handle some goitrogenic foods and others say since you are eating fermented foods in small quantities that you shouldn’t worry about it. I also read that fermenting increases goitogrens but decreases nitriles which is more dangerous. So I would say eat them in small quantities and not worry about it. But that’s not medical advice of course. Thanks! I am not firmed up about all of this but I think moderation is likely the key.

  14. JudyG Van.BC says:

    I am relatively new to this whole thyroid thing and it all seems very complex. I have recently been diagnosed with non-symptomatic nodules in my thyroid, one of which being larger needs to be biopsied (waiting). Apparently my blood work was fine and did not show hyper, hypo, Hashimoto’s, Graves etc. Am I at risk to develop these? Do I need to avoid cruciferous/goitrogenic foods? Have been doing a lot of online research, but this is not an easy topic!!! I am glad to have found this site.?PS just started adding organic fermented foods to my diet?!

  15. I’m interested in the Berkley filter that was mentioned in an article I read about removing fluoride from diet. Am I asking the right person?

  16. I was diagnosed with Hypothyroidism when I was about 44 yrs old – Took 2 yrs to finally get it straightened out but gained 50 lbs. Then found out I had feet problems (plantar fisistas (spelling)) had breast cancer, mastectomy, reconstructive surgery & ended up gaining more weight.

    As for soy products – I feel that is why I developed hypothyroidism – because I had begun eating lots of prepared Soy-based meals because I kept hearing that soy was ‘good’ for you. – they tasted so bad I had to add Salsa. Thankfully I quit but just about a month later is when I developed hypothyroidism. – I had decided to lose 5 lbs in a week (just eating a salad at night) – no problem before. Instead of losing I gained 5 lbs and within 2 days I was extremely tired- worse than I had ever felt before became depressed & kept gaining weight.
    It was this that had me searching for what caused the thyroid problem & found out problems with Soy so have done my best for over 15 yrs to not eat anything with any soy products.

    – Fast forward to 2014 – I began watching Know The Cause with Doug Kaufman & in April, 2014 began the Phase 1 diet – even with some ‘cheating’ – I have lost 40 lbs without trying & I was eating full-fat greek yogurt; full-fat cream cheese, etc. while also eating Quinoa, grass-fed & grass-finished meats, & organic produce, etc. My biggest surprise with this diet – I began to eat & like veggies that I usually only ate sometimes & then not much.
    As for the cruciferous veggies, I’ll make certain they are cooked before eating – which is good to know because I kept thinking I should eat more raw.

    I still get tired but at 63 yrs old & to be able to lose weight that I’ve not been able to for years is fantastic! (and without even trying to lose – Honestly, I had just given up on that)

    So if there is anyone even without a thyroid problem but want to lose weight – go Gluten-Free, eat the right meats & veggies. Of yes, and NO Sugar.

    • I used to eat a lot of soy as well….but that was well after when I had hypothyroidism in college. It was just borderline then. I’m glad to know I’m not the only one who “cheats” :)! Good for you for doing so well! I think iron is a crucial thing to check – and vitamin D. Have you done that? Take care!

      • No haven’t checked iron or vit. D. Couldn’t even get doc to do a complete thyroid test – T3 & T4 – I was told they only do that to determine whether someone has thyroid problems & since I have this – no reason to do the test again…. – despite why I asked.

        But I may buy some iron & just get in the sun more to check those out myself.

        • That, in my opinion, is really irresponsible of your physician. Did he check for TPO? I would personally be going to a different doctor, if that is an option.

          I would be careful about iron overdosing – not medical advice, but please look that up. And maybe you can find a physician who will test your vitamin D and iron. You are paying him, right? They need to do things to help you get better. You can order your own tests if you can afford it, through other labs. I did that this past time. My doctor wouldn’t order everything I wanted.

          • No blood work this visit and I will be going to another doctor just haven’t looked for one yet.

            Yes I know to check the iron part so I’ll be careful. I have thought of ordering my own tests for a couple of years but no I can’t afford them. So I’ll just wait & see.

  17. AJFlamingo says:

    I was first diagnosed w/ thyroid cancer 30 years ago. It recurred 5X. I was familiar with most of the concepts you present.

    I haven’t had any healthy thyroid tissue left for years. I had a “total” thyroidectomy at 27. Married only 18 months. Little did we know how fast and forever our life could and would change. However, the first surgeon only “got as much as [he] could given the incision [he] made.”
    I would have a neck section within a year. It would not be the last.

    I have changed my diet over the years: getting healthier and healthier. Now that I’m listening to my body, I find I actually DON’T like cruciferous veggies. Never have.

    I supplement with Vit.D and drink more or less 4 glasses/cups of 2% organic milk/day. I have -0- signs of bone loss. Losing bone mass and osteoporosis are common side effects for ThyCa patients and more so for women.

    Whenever I felt a new tumor, I always headed to my oncologist and we got started immediately (verifying there was a “real”
    cause for alarm by scheduling a biopsy immediately). He actually never discovered new tumors, I did.
    And honestly, I had dreams I was “sick again” and when I woke up, my hand flew to the new one on my neck.

    You’ve done an excellent job presenting the facts on nutrition
    as it relates to the thyroid.

  18. Disagree with Gluten Free
    This is true for the US, but not for Germany or other EU Countries.(I am from Germany)
    No Doctor will advise you there to stay of Bread or other Food containing Gluten.
    Gluten is a vital part of a Healthy Diet. Unless you are Gluten intolerant or suffer from Celiac there is no reason to eat not bread.

  19. Would it make a difference in my reboot if I were to cook these particular veggies prior to juicing them. Or should I just stick to the short list until I’m done? Thank You so much for your time.

    • Research shows that cooking deactivates many of the goitrogens so … the answer is it all depends. There are some thyroid issues that are due to too much iodine and others that are due to too little so it really depends on your situation. I’m not sure what kind of a reboot you are talking about.

  20. This is great and all true. However, I have tried for years to fix my thyroid but could not get it completely working properly. I then had my mercury fillings removed. I got rid of my restless leg syndrome, restored my eye sight, and I was finally able to get my temperature up near normal, 97.8 up from around 91. The mercury in your mouth is probably causing your thyroid problems. There is also mercury in high fructose corn syrup.

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