Are Cruciferous Vegetables Bad for Thyroid?

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Do Cruciferous Vegetables hurt the Thyroid
Wellness Mama » Blog » Health » Are Cruciferous Vegetables Bad for Thyroid?

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

This is the advice most of us know to be true — that if we eat our veggies, and lots of them, we will be healthier… right?

I always thought so, until I was diagnosed with Hashimoto’s, an autoimmune condition affecting the thyroid. I read a lot of information about how people with thyroid problems should stop eating cruciferous vegetables, such as broccoli, cabbage, or cauliflower.

Unfortunately, these are some of my favorite vegetables! As I dug into the controversy, I found some sources claim that all cruciferous veggies should be avoided, while others say it’s okay to eat them if they’re cooked. I also read that it’s recommended to take a natural iodine supplement to support the thyroid when eating cruciferous veggies.

With all that conflicting information out there, I needed an answer to this question for myself.

I asked my doctor’s opinion on cruciferous vegetables, and his answer (combined with my own independent research) assured me that it’s perfectly safe to consume these vegetables regularly.

Here’s why:

What Are Cruciferous Vegetables?

First, a recap: cruciferous veggies are a hearty group belonging to the mustard family. They’re named for the Latin word Cruciferae that means “cross-bearing.” This term refers to the four petals of leaves on the plant that resemble a cross.

You might know that kale and broccoli are cruciferous veggies, but there are many more beyond those staples. Other cruciferous vegetables include:

  • Arugula
  • Bok choy
  • Brussels sprouts
  • Cabbage
  • Cauliflower
  • Collard greens
  • Horseradish
  • Mustard greens
  • Radishes
  • Rutabaga
  • Turnips
  • Watercress

These types of veggies are generally very healthy for you (read my post on broccoli sprouts if you need convincing), but you might have heard mixed things about eating them if you have a thyroid disorder.

Here’s a breakdown of why cruciferous vegetables are controversial, and why I think they’re safe to eat anyway.

Why Cruciferous Veggies Are Good For You

In my opinion, cruciferous vegetables represent some of the healthiest foods out there.

Most notably, this class of vegetables are protective against different types of cancer, including breast, lung, colorectal, and prostate cancers. This is all thanks to glucosinolates, a sulfur compound available only in cruciferous veggies. It’s what gives those veggies a pungent, slightly bitter taste.

Plus, cruciferous veggies are packed with health benefits. They’re an excellent source of minerals, like folate and fiber, and vitamins like C, E, and K. They also contain powerful phytochemicals that may help soothe chronic inflammation and reduce the risk of cardiovascular disease.

Too Much of a Good Thing?

The problem with cruciferous veggies is that they contain goitrogens, which are substances that affect the thyroid gland. Specifically, goitrogens mess with the thyroid’s ability to take in the essential mineral iodine. Your body needs it to produce thyroid hormone. If you don’t get enough iodine, it can lead to a bulge in the throat known as goiter.

This is especially problematic for people who already have an underactive thyroid and don’t want to slow it down further.

Cruciferous veggies aren’t the only foods to contain goitrogens. Other goitrogenic foods include:

  • Peaches
  • Peanuts
  • Red wine
  • Soy products
  • Strawberries
  • Sweet potatoes
  • Teas (green, white, oolong varieties in particular)

Peanuts and soy products aside, I wouldn’t go out of your way to avoid goitrogens. The health benefits of the food often far outweigh the negatives. This is because most people have an excess of iodine in their diets and not a deficit.

Why Eating Cruciferous Veggies Is Probably Safe

Despite the presence of goitrogens, I think the benefits of eating cruciferous veggies outweigh the negatives — even if you have thyroid problems.

That’s because you would have to eat enormous amounts of cruciferous vegetables to affect the thyroid. And I’m not sure many of us have the problem of overeating vegetables!

So far, there has only been one case study where too many cruciferous vegetables harmed the thyroid. In this case, an 88-year old woman developed hypothyroidism after eating two to three pounds of raw bok choy every day for several months.

So unless you’re eating several pounds of cruciferous vegetables daily, you are probably in the clear!

But What About Getting Enough Iodine?

Since cruciferous veggies mess with the thyroid’s ability to take in iodine, you might be concerned that your levels are too low. However, in today’s world it is pretty easy to have too much iodine, which 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, as selenium can help mitigate the toxic effects of too much iodine in the thyroid.

My doctor Dr. Alan Christianson 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 are clear of iodine deficiency problems, so cruciferous vegetables are almost always a non-issue.

On the other end of the spectrum, too much iodine can increase your risk of autoimmune disease. This is evidenced by higher rates of autoimmune thyroid disease in Greece after iodine was added to the food supply.

In these cases, the mild iodine inhibition from cruciferous vegetables can actually be helpful for those with thyroid problems.

Plus, cruciferous vegetables may help the body produce glutathione, an antioxidant that can boost thyroid health and fight autoimmune disease.

So in other words, cruciferous veggies might actually be helpful for thyroid disease in many cases!

How I Minimize Goitrogens

If you plan on eating a large amount of cruciferous veggies, such as in the Wahls Protocol, and are concerned about any effects on your thyroid, there are easy ways to reduce the chance of any negative side effects.

1. Cook Your Veggies

If you’re still concerned about goitrogens, just be sure to cook or ferment your veggies instead of eating them raw. This will deactivate most of the goitrogens.

For example, if you drink green smoothies, consider blanching the spinach or kale ahead of time, then freeze until ready to blend.

2. Get Enough Iodine and Selenium

It also helps to make sure you’re getting enough iodine and selenium. Some great selenium-rich foods include:

As for iodine, you don’t need to stick to table salt to get your fill. Try these healthy iodine sources instead:

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.

Why I Don’t Recommend Supplementing With Iodine

You might be tempted to add an iodine supplement to your routine so you can safely eat more cruciferous veggies.

However, I don’t suggest trying one. A large intake of iodine can mess reduces the thyroid’s ability to produce hormones.  I learned this the hard way when my chiropractor recommended that I go the supplemental route. I immediately felt worse!

In most cases, it’s best to stick with natural and healthy sources of selenium and iodine while battling a thyroid problem. Pay attention to how your body adjusts to the extra intake of nutrients, and adjust your diet accordingly.

The Bottom Line

Cruciferous vegetables provide a variety of benefits, even (and especially) for those with thyroid disease. Of course, if you or your children are hypothyroid or battling autoimmune disease, you should work closely with a qualified doctor or functional medicine practitioner to find the best diet, medication, and lifestyle to fit your needs.

This article was medically reviewed by Dr. Terry Wahls, a clinical professor of medicine and clinical research and has published over 60 peer-reviewed scientific abstracts, posters, and papers. As always, this is not personal medical advice and we recommend that you talk with your doctor.

Do you suffer from a sluggish thyroid? Do you eat cruciferous veggies? Tell us about your experience in the comments below!

Katie Wells Avatar

About Katie Wells

Katie Wells, CTNC, MCHC, Founder of Wellness Mama and Co-founder of Wellnesse, has a background in research, journalism, and nutrition. As a mom of six, she turned to research and took health into her own hands to find answers to her health problems. is the culmination of her thousands of hours of research and all posts are medically reviewed and verified by the Wellness Mama research team. Katie is also the author of the bestselling books The Wellness Mama Cookbook and The Wellness Mama 5-Step Lifestyle Detox.


53 responses to “Are Cruciferous Vegetables Bad for Thyroid?”

  1. Lea Avatar

    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!

    1. Sarah Avatar

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

  2. Chelle Avatar

    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?

  3. Crystal Avatar

    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!

  4. Heather Tupps Avatar
    Heather Tupps

    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!

  5. Helen Avatar

    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

  6. Oliver Avatar

    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

  7. Ikuko Avatar

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

  8. Tanya Townsend Avatar
    Tanya Townsend

    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 🙂

  9. Jacqui Avatar

    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.

  10. Maci Avatar

    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?

  11. Dr Sarah Brewer Avatar
    Dr Sarah Brewer

    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.

  12. Erin Avatar

    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.

    1. Naomi Aldort Avatar
      Naomi Aldort

      I too have read Dr. Brownstein’s work and I take lots of iodine daily and it is fantastic for me. He shows that actually today, many people are very low on iodine (becoming hypothyroid is an epidemic) and explains not only why it is safe, but absolutely necessary for MOST people to take, not the tiny quantities, but large quantities of iodine supplement. He teaches how to take it for most benefit, combined with other minerals and away from food. You may wish to explore his work. What you say here is more or less the mainstream thinking and the established physician point of view. I hope you explore Dr. Brownstein’s work and others like him and update your writing. Thank you for constantly learning and passing on.

  13. Lindsey Avatar

    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.

  14. Ellen Avatar

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

  15. Terry Avatar

    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.

  16. Dee Avatar

    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.

    1. Michelle Avatar

      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

      1. Dee Avatar

        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. 🙂

      2. Lindsey Avatar

        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.

      3. Terry Avatar

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

    2. mandy Avatar

      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

  17. Rene Hinds Avatar
    Rene Hinds

    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..

  18. Tanja Odzak-Goppold Avatar
    Tanja Odzak-Goppold

    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)

    1. mandy Avatar

      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)

  19. Marny Avatar

    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 🙂

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