Thyroid Problems & Cruciferous Vegetables

Do Cruciferous Vegetables hurt the Thyroid

Cruciferous vegetables are some of the healthiest foods on the planet, and some of my personal favorites to eat. When I was diagnosed with Hashimotos, I found out there was a lot of confusion on whether or not those with thyroid problems should continue eating them.

Some sources claim cruciferous veggies should be avoided, especially raw, while others say they are fine to eat but recommend taking a natural iodine supplement to support the thyroid when eating cruciferous veggies.

I needed an answer to this question for myself.

When my doctor recommended eating broccoli sprouts, I asked his opinion on cruciferous vegetables. His answer and my research made me comfortable consuming these vegetables regularly… here’s why:

Glucosinolates and Goitrogens, oh my?

Cruciferous vegetables contain glucosinolates; which are metabolized into isothiocyanates (ITC) in the body. Research shows that these compounds are protective against various types of cancer. (1) Cruciferous veggies are also an excellent source of vitamins, minerals and phytochemicals that support the body in various ways.

At the same time, these veggies contain goitrogens, which can inhibit the body’s uptake of iodine. Research in animals showed that this blocking of iodine uptake may contribute to the development of a goiter, which is the reason that cruciferous veggies are often not recommended for those with thyroid disease.

So what is a person with thyroid disease to do?

In my opinion? Eat the greens.

Iodine, Selenium and Animal Studies

Dr. Joel Fuhrman explains:

Animal studies suggested the hypothetical thyroid issue from eating very large amounts of cruciferous vegetables years ago. However, no human study has demonstrated a deficiency in thyroid function from consuming cruciferous vegetables. Only one such study seems to have been conducted as of yet; in that study, no effects on thyroid function were observed in subjects eating 150 grams of cooked Brussels sprouts daily for 4 weeks. Raw cruciferous vegetables have not been investigated, however the only case report relating cruciferous vegetables to thyroid harm suggests that it would be almost impossible to consume enough cruciferous to harm the thyroid. This case was that of an 88-year old woman who developed hypothyroidism after eating 1-1.5 kg (2.2-3.3 pounds) of raw bok choy every day for several months; an excessive and unreasonable intake of raw cruciferous. In other words, a person would have to consume an insane amount of raw cruciferous to have a negative effect on thyroid function.

In fact, the opposite is actually true.

In today’s world, it is easy to have too much iodine, which as I explained before can be just as detrimental to the thyroid (and was for me). This is especially problematic if there is a deficiency in selenium as well. (2)

My doctor explained that if a person’s thyroid disorder is not caused by iodine deficiency, the iodine blocking properties of cruciferous vegetables are nothing to worry about (especially if the person is eating a nutrient dense diet that contains natural sources of iodine and selenium). He estimates that over 90% of thyroid patients have autoimmune thyroid disease and not simply low thyroid function because of iodine deficiency so cruciferous vegetables are almost always a non-issue.

In fact, too much iodine can actually be a factor in increased risk of autoimmune disease. In countries where iodine was added to the food supply to combat thyroid disease, rates of autoimmune thyroid disease increased. (3)

An excess of iodine, especially in supplemental form, can increase autoimmune attack on the body by inhibiting the ability of an enzyme called thyroid peroxidase (TPO). In these cases, the mild iodine inhibition from cruciferous vegetables can actually be helpful for those with thyroid problems.

Additionally, cruciferous vegetables may help the body produce glutathione, an antioxidant that is important for thyroid health and for mitigating autoimmune disease. Broccoli and broccoli sprouts contain sulforaphane, a cancer-fighting compound that has been extensively studied for its anti-cancer properties.(4)

Bottom Line?

Cruciferous vegetables are healthy and provide a variety of benefits, even (and especially) for those with thyroid disease. Of course, anyone with thyroid disease or any other health problem should work with a qualified doctor or functional medicine practitioner to find the best diet, medication, and lifestyle answers, but the existing medical evidence does not suggest that avoiding cruciferous vegetables is helpful.

In fact, cruciferous vegetables may be especially helpful for those with autoimmune thyroid disease because of their iodine-mitigating action. Consuming 2-3 pounds per day of raw green veggies would probably not be advisable, but then again, consuming 2-3 pounds of any single food group daily isn’t the best idea. If you’re concerned or think you might have non-autoimmune low-thyroid, just cook the veggies as this is shown to deactivate most of the goitrogens.

Personally, I eat a lot of green vegetables daily and consume about 75% of them cooked and only 25% raw. I also make sure that my diet contains natural sources of selenium and don’t supplement with iodine.

“Eat food, not too much, mostly plants.” -Michael Pollan

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Reader Comments

  1. Interesting. I just ordered a big 1kg bag of maca powder and chose raw because it retains all the nutrients in it. But then I read another post about it being a cruciferous root and possibly a goiterogen so that particular blogger recommended the gelatinized version. I don’t have thyroid issues (that I know of) but I still wondered if I had made the wrong choice. This post makes me feel much more comfortable with the raw powder now! Thanks for the info 🙂

  2. Have you checked out Izabella Weitz book on Hashi’s? Great read!

      • Yay, bravo!

  3. What foods are natural sources of iodine and selenium?

    From a quick Google search on iodine, the following comes up: Eggs, Dairy, Seafood.

    If one happens to be allergic to all those items, is supplementation suggested?

    (my 2yo is allergic to all of them… except can now tolerate butter)

    • brazil nuts are a great source of selenium. Dairy is only a good source of iodine if it is commercially produced non-organic milk – the iodine content gets into the milk from a substance they use to clean the milking equipment, not from the milk itself. commercial dairy produce is not recommended for anyone with autoimmune or thyroid issues as it also contains antibiotics and hormones that were injected into the dairy herd. levels of iodine in seafood can vary greatly and I don’t think can be easily predicted. levels of iodine in seaweed is high. I have graves rather than hashi’s so do not try to increase the iodine in my diet, but I do cook (and lacto-ferment) using himalayan pink salt – I believe the color comes from its iodine content – although salt shouldn’t be used as a means to supplement iodine or other minerals, it is a way to include trace minerals in the diet (which are not found in table or highly processed salt)

  4. Thanks for this valuable piece of information, Katie! I, too, have read much about how people with low thyroid should avoid crucifers. It’s very good to find out that I can eat them with impunity.

    The tip about too much iodine is also a revelation to me. What is your take on what a person should include in their diet if they are seeking to restore their thyroid gland to normal function? As Hippocrates said, let your food be your medicine..

  5. With due respect to your research. I have to disagree with your results. I also have Hashimoto’s. It wasn’t until I did my own research, then met with a couple of ladies with Graves’ that I did the opposite. They had increased their intake of cruciferous vegetables and were controlling their Graves’ naturally that way. I on the other hand, love those green but left them alone for almost year. Not taking any meds for thyroid, just having an occasional dish of those greens, now my thyroid has recovered and is in the normal level. My endocrinologist couldn’t be how I did but the lab showed the truth.
    I’m not saying you aren’t correct, just that not all fit into what some docs believe. As I did, sometimes you have to get to know what the body is saying instead of treating the symptoms. We are still learning a lot about our bodies but doctors can be ‘blind’ to alternatives from what they have learned. Just my experience.

    • Hello 🙂 I have Hashimotos as well. Would you kindly comment if perhaps you are doing anything else that has helped maintain your healthy thyroid levels. I am desperately trying to stay off of meds but my numbers keep rising. I tend to stay away from crustiferous greens and supplement with selenium, vitamin D, curcumin, fish oil and probiotics. I’d appreciate any input, thanks

      • Hi Michelle,
        It was when I stopped trying to find balance by just focusing on my Hashi’s that I began to build from the inside out. By that I mean, if the thyroid is out of balance, then the body will try to compensate somehow, so I began with my immune system to strengthen it first. I didn’t start with anything more than lowering my blood pressure. Which I did, then I discovered that learning just what I am eating really did make a difference. I’m not talking just carbs, proteins etc, but down to the nutrients our food has and what each food did for the body. I included especially the herbs and spices I cook with. I have been amazed at the nutritional and health benefits that such small amounts and combinations of these do so much for my health.
        I make my own herbal/spice blends now so I know there are no bulked up mixes in my food. I eat whole foods, and very important.y, I’ve learned to listen/feel what my body is telling me. This didn’t happen quickly, but the time of learning sure has paid off. I now enjoy the foods I eat because I know how they are helping my body. I’ve now taught my daughter to do the same thing. She’s learning faster than me. 😉 lol I don’t do supplements because I can get everything needed from the food I eat. Vitamin D? Did you know if you leave a couple of mushrooms on a kitchen window for the day and cook with them for the evening meal, you can receive from them a week’s worth of Vitamin D? True and they seem to taste better too. 🙂 Fish oil? Once a week I include a can of sardines in my menu and it’s all my body needs for the fish oil. I have increased the amount of pickled and fermented foods which I hadn’t been eating before. I did this when I discovered the body has taste buds for sweet, sour, salty, and bitter for a reason, assist us in knowing how much of each we need daily. So start with a detox, then begin to learn one food at a time, just how YOUR body works. By all means, Katie’s help here has assisted me in my path. Keep at it Katie. 🙂

        • Windows fliter the rays that give us vitamin d.

      • Try coconut oil. It is great for the thyroid. I eat 2 tablespoons a day. I also use coconut oil in the mornings to pull toxins out of my body (research pulling to learn more). Apple cider vinegar (raw) is good as well. Be sure you are getting enough iodine; vital to thyroid health. Also, stay away from peanuts and soy.

      • Type in “Thyroid” in the search box on Wellness mama. She has many posts concerning thyroid health.

    • I have Graves and discontinued treatment after 3 months. I then spent a long time trying to figure out how to control the condition without meds. My first port of call was goitrogens, which I ate, raw, with abandon – it made no difference and I continued to become increasingly hyperthyroid. I have been a member of a number of support groups containing thousands of members and have yet to come across anyone with hyperthyroidism who has successfully controlled the condition by use of goitrogens, although many have tried. In the end the solution for me was to cut out gluten, processed foods, processed sugar, grains and pseudo-grains, pulses, dairy, commercially produced meats, and to severely limit consumption of nightshades. Cutting out gluten being the most significant of these. and to include lacto-fermented vegetables. I now also include a little lacto-fermented organic dairy – 1 ltre a week of kefired goats milk which I usually make cheese with. From my own experience, I would say if you have autoimmune thyroid disease, look to heal your immune system rather than control your thyroid. 80-90% of our immune system is made up of our gut bacteria – healing our guts and eating to ensure we have good healthy well nourished bacteria is key to healing the disease, in my humble opinion and based on my experience of what has worked for me. Good luck xx

  6. I’m so glad you gave us this information! I love broccoli and didn’t want to give it up, knowing it has many other nutrients. I was hesitating to make the sauer kraut too. Now it’s full speed ahead because I highly doubt I have an insufficiency of iodine.
    Do you regularly eat Brazil nuts for your selenium intake? If not, what? I have a smoothy almost every morning, which includes ground Brazil nuts. I’d like some variety though.

  7. What food sources of selenium do you find that have useful amounts of that nutrient?

  8. Hello Wellness Mama, thank you so much for your great posts! I enjoy the information you share.

    I read another post today that you created awhile back about the Sole drink. Do you still consume this drink daily in the mornings since it is salt? Just curious with your thyroid disease. I too have hypothyrodism and want to try to heal my thyroid the best I can naturally (I know you can’t give medical advice), just curious about the Sole and thyroid correlation for you personally.

    Thank you.

    • I do still consume it about every other day in small amounts (about a tsp)

  9. Gluten intolerance is what causes the initial breakdown of the thyroid.Study Dr. Brownsteins work (he goes agaijst the conventional thyroid theories like u mmention) and has successfully cured patients. Too long to tell here but after reading his work and success you will understand why everything you just said is completely false.

  10. Cruciferous vegetables protect against numerous cancers too, and are one of the components of the Asian diet which is thought to account for their low rate of prostate cancer progression.

  11. I had Hashimoto’s at 16 – now 61! My understanding was that it had permanently “killed” my thyroid and have taken synthroid or Thyroid strong ever since ( went to Thyroid strong for more ” natural” alternative but see no different in effect). Ideas?

  12. Hi I have nodules on my thyroid too. I’m not taking any medicine yet because they say my levels are in range. I do have higher antibodies. The docors tell me eventually it will lead to Hashimotos. I’ve been researching as well, it says all over that cruceferus veggies are not good. Well, I did an experiment with myself. At one point I was making chicken soup with Kale, and lots of other veggies in it for about a month. I would eat it 2-3 times a day and guess what I went to get my thyroid checked with blood and ultrasound (as I always do yearly) and they said the nodules actually shrunk! My thoughts are that the soup with kale and veggies might have actually helped me. This leads me to believe that there is more to this Hashimotos disease then they seem to let on. . But in conclusion, what you are saying definitely sounds correct. Thank you so much for your information it’s very informative. Keep up the info.

  13. Hi, the inhibiting affect that the goitrogens have, it only occurs if the cruciferous vegetables are eaten raw, the thing to do is to steam all the cruciferous vegetables as this stops that – yay 🙂

  14. Thank you for your valuable information!! I really enjoy reading them.

  15. Yes Erin is right, the article is okay but gets it completely wrong in relation to Iodine. We have successfully treated 1000s of thyroid and hashimoto’s using Iodine therapy alongside the functional approach

  16. Dear Katie, I love your website. I have taken many tips from it and thank you for everything. In example how you should eat to have healthy teeth. You said you have Hashimotos. Im sorry to hear that. How is it going now? I have a question. You must have heard about eating kosher? I have started eating kosher because I am a christian and want to follow God’s Law. I also stopped eating dairy and meat, fried foods, sweets and sugary beverages. My life has improved much. I hope eating Biblically might be of help to you. I personally know it would be. God bless you 🙂 thank you for putting sincere effort into your website, it shows :)!! kind regards, Helen

  17. Great article. There is a lot of confusion around whether or not those with thyroid problems should avoid cruciferous vegetables. While I think it’s best to not eat 2 lbs of raw kale in smoothies everyday, It feels wrong to think that a sauerkraut addiction could be a contributor to Hypothyroidism.

    I think it’s much more important to tackle the basic things, like making sure your water is filtered free from fluoride and not sleeping with your cell phone by your head!

  18. How would I know whether or not my issue was due to iodine deficiency? I had a hot spot/nodule on my thyroid several years ago that was causing hyperthyroidism. (It was treated with radioactive iodine therapy, which thankfully did not completely destroy my thyroid function.) I never was clear about the cause. I had always been told to avoid cruciferous vegetables, so this information was really interesting to me. Thanks for your help!

  19. Interesting article. I wonder if the same goes for using a healthy soy like Bragg Aminos. I currently avoid it now, but I often wondered how much soy is bad for the thyroid?

  20. There’s a brand of vitamins called Vitamin Code whose vitamins are all made of or contain raw cruciferous vegetables. They come in a vegetable cellulose pill. Would it be safe to take such vitamins daily such as there vitamin D3, vitamin C, etc? Thank you for your feedback!

    • Did anyone ever answer this question? I take the same vitamins and also have Hashimoto’s.

  21. I have an under active thyroid gland and have just heard to avoid all cruciferous vegetables. In checking up on line some websites say that spinach is cruciferous and some say it isn’t. Could anyone clarify this as I consume a lot of spinach in my juices and really don’t want to give them up.

  22. This is a great article! I shared it on for you 🙂

  23. This article goes against everything I have reasearched and belueve in. You are giving people permission to do the exact oposite of what wd ar supposed to do tohelp our low thyroid. I am undef tge care of my accupuncturist and on a regimine that knclodes selenium 200 mcg and 50mg of iodine/iodide…your thyroid is blocked by toxic halides (floride, bromide etc.)which mimic iodide therefore blocking it. You have to eliminate those toxic copycats before iodine can even start getting to your thyroid. Takes abpit 3 months. Don’t start iodine without knowing how to ease into it.

  24. I live in a selenium-poor area, so I supplement daily with 100mcg of selenoprecise, which is an organic selenium supplement. That along with zinc orotate has been great for me. My hair was thinning in the middle and it has made a nearly “full” recovery. Has anyone else had any good experience with selenium?

  25. If raw cruciferous veggies are fermented do you know if that is the same as cooking as far as deactivating the ant thryoid aspect?