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Is eating kale going to kill your thyroid?

By Robyn Openshaw, MSW | Jan 20, 2014

I have a number of people asking about kale, since a New York Times columnist recently implied that her diagnosis of hyperthyroidism could be related to eating kale. And flax.

Never mind all the devastating endocrine disruptors out there, like chlorine and fluoride in our water, BPA and phthalates in plastics we drink from. Those are not even mentioned in her totally unscientific opinion that I believe people are giving too much attention and credence to.

The journalist congratulates herself on being a “health nut,” I assume to establish her credibility on health topics? But she seems to have no idea that soy is bad for you. (Qualifier: mostly because it’s very genetically modified, and shows up in the food supply as processed, fractionated products.) That has been known in a pretty widespread way for 10 years, to anyone following health trends and research at all.

She is a journalist, not a researcher, practitioner, or subject matter expert. She quotes exactly zero studies or experts. It’s simply an opinion editorial—with an inflammatory title. My only point here is, don’t over-invest in this concept that kale is going to wreck your health.

Here’s one of the journalists who, in response to that editorial in one of the most widely read publications in the world, actually took the time to dig deeper and understand whether or not kale is really a problem:

Remember that it’s practically a sport in the media to stir the pot. Being controversial gets readers. Creating a maelstrom sells newspapers and causes stories to go viral.

Even in that story, above, which is a far more sensible treatment of the same subject, the author teases by saying, yes, maybe kale is bad. Then she goes on to quote a number of sources who assure us that kale is nutritionally spectacular and a good part of a healthy diet as long as you have iodine and selenium in the diet, just, don’t go crazy with it.

The sensationalism gets you to keep reading. Beware of gimmicks.

The “information age” with everyone on the internet having an opinion has led to a great need to use your critical thinking skills, consuming information.

I’ve written about goitrogens and thyroid before. I’ll boil down some salient points, in response to this latest firestorm:

1.     A number of studies show that even 5 oz. of crucifers several times a week had no negative impact on thyroid function. Surely going bonzai with bok choy isn’t the same thing as making a variety of cruciferous vegetables of your regular diet. (The “scare” stories come from people eating a ton of the same food for long periods of time.) I see this often in sensationalism in the media. (For instance, the guy who turned blue from using colloidal silver. What people don’t know is that he drank a CUP of silver daily for many years!)

2.    The New York Times columnist’s suggestion that kale somehow led to her thyroid problem is a non-sequitur logical leap and fallacy, since correlation does not prove causation. That’s Latin for “it does not follow.”

(I had several friends who got divorced in 2007. And I got divorced that same year. Research says people who have friends getting divorced are more likely to do the same. Therefore, my friends’ divorces caused mine. You shouldn’t be friends with people who get divorced. You get how problematic the logic is here?)

Let’s follow this journalist’s logic:

I was diagnosed with thyroid problems. I eat kale sometimes. Kale is part of the cruciferous family, which may or may not contribute to thyroid problems in the absence of iodine, according to a few case studies. Therefore kale caused my hypothyroidism and is bad for you.

There are so many chemicals in our environment that damage the thyroid. She couldn’t have known that her opinion piece would go viral, of course. But since the Times has a readership of millions, it sure would be nice before an editorialist maligns an amazing green food, if she would analyze the problem from a variety of angles. I would imagine that what many people got from that is, “Kale is bad for me.”

3.  Hypothyroidism is virtually an epidemic, with some experts estimating that 25-50 percent of women have low thyroid function, many of them undiagnosed. Surely that epidemic didn’t happen because Americans eat too much kale. Americans haven’t eaten too much kale in the past 50 years, period. Most Americans still don’t eat kale, ever.

4.  Many compounds in greens are nurturing to the thyroid. Abandoning them seems unwise. Goitrogenic compounds that can, in extreme cases of over-consumption, without iodine, contribute to goiter, are just one class among many of nutritional properties in this food.

5.  Getting enough iodine may negate any negative effect for the rare person who has a problem with crucifers contributing to a thyroid problem. So says Dr. Jeffrey Garber in the Commonhealth story I’ve linked to above. Dr. Barbara Jennings, in Denver, an auto-immune specialist, also referenced this issue in our live detox call last week.

The story I’ve linked to, however, also refers to Americans not having an iodine deficiency. Dr. David Brownstein, MD, says otherwise. He believes we are mostly iodine deficient and in his book on the subject calls iodine the “most misunderstood nutrient.” He advocates for iodine therapy for ADHD, autism, many cancers, and thyroid diseases like Hashimoto’s, Graves’, and hypothyroidism.

I personally take five drops of Lugol’s iodine in water daily. It’s available on the internet or health food stores, and kelp or dulse (seaweeds) are a whole-foods source. They contain natural iodine. You can season popcorn, soup, or anything savory with them, or put them in your smoothie.

(I was diagnosed at 34 as hypothyroid. My good diet has brought my thyroid back to 80% functioning. I continue to work on heavy-metals detoxification in hopes of restoring 100% function. Meantime, I take a bioidentical thyroid rather than a drug.)

You have to take careful note—if you notice a racing pulse, you may have overdone it with iodine. This is not precise, for purposes of troubleshooting your own health. My telling you that I take iodine, and how I know if I’m getting too much, shouldn’t be inferred wholesale, to your own health issues. This is just standard practical advice that practitioners give. I am mildly hypothyroid, and 135 lbs., and they say I should take 5-6 drops of Lugol’s solution, and if I notice heart racing, I should back off the dose.

Keep in mind I’ve experimented with this under the care of my bio-identical hormone practitioner (usually they are nurses with master’s degrees, and sometimes doctors).

So, best to go to a bio-identical hormone specialist for balancing the endocrine system in a far more natural way than the “Standard of Care” drug approach. (The thyroid drugs that docs prescribe are not molecularly the same as the thyroid your body produces. They also cause risk of cancer and other problems.)

Best if you can get a full blood panel test, for not just T3, but also for all the factors upstream and downstream of it, precursor hormones and hormones. A good practitioner can analyze the interplay of those factors and recommend a course of action that can have you feeling better soon.

You can google your city and “bio-identical hormone” to find a practitioner near you.

6.  Working with a good naturopathic doc who knows a lot about these issues may be helpful, if you suspect or know you have thyroid issues. (Google hypothyroid symptoms for some clues.) Find someone with more than just a cursory understanding of the issues. I have found that some practitioners say, “Cruciferous vegetables can be a problem for hypothyroid patients, so don’t eat any.” This makes me wonder if they have  a knowledgeable, balanced approach like the experts quoted in the story above, or if their knowledge of nutrition is really quite limited. Quiz them to learn how experienced and knowledgeable they really are. And don’t depend entirely on practitioners for information—be your own best advocate, and research on your own, so you can start at a higher place with working with a holistic practitioner.

Watching and measuring your own thyroid response, and overall wellness, relative to the quantity you eat, of this amazing class of greens and vegetables, may be wise.

7.  I personally have found significant quantities of greens (not all of them crucifers) to be a critical component in healing my own thyroid of radiation exposure, since I was a “downwinder” baby during the Nevada Test Site radioactive detonations in the late 1960’s. (Radiation is well known to depress the thyroid, and cause thyroid cancer.) “Goitrogenic” greens and veggies have many thyroid-nourishing compounds as well, and massive anti-cancer benefits. I use a variety. It’s fair to say I eat about 5 servings a week of kale, broccoli, cabbage, bok choy, etc.

8.  I’m not a big fan of the “cook it to neutralize the anti-nutrients” advice. Sure, you’ve addressed one issue, goitrogens—but you’ve also killed all the living enzymes and damaged or destroyed most vitamins and minerals. I’m a fan of steamed broccoli and cauliflower, by the way (otherwise I would eat those vegetables only rarely)—but also a big fan of eating 60-80% raw plant food at every meal.

9.  Why the big preoccupation with kale, specifically, anyway? There are collards, chard, beet greens, varieties of spinach, cabbages, celery, spring greens available organic year-round, and so many other choices. They are all good, and they all have a different nutritional profile. A variety helps keep us in balance. Mix it up!

I really hate to see unhealthy people bailing on a whole class of the most nutrient dense foods available to us, because of a “tempest in a teapot” buzzing on the internet.


Posted in: News, Nutrition

32 thoughts on “Is eating kale going to kill your thyroid?”

Leave a Comment
  1. Suzn Reazin says:

    Thank you for this, I love your blogs.

  2. Sophie says:

    Thank you Robyn. So much conflicting information out there to wade through. On a different food subject, agave, would you still recommend the Sun Drenchers dressing?

    1. Robyn says:

      Sophie, it’s fine….wish it were lower in agave. I like dressings to be mostly flavor, not so much sweetener and oil. But they do a good job with sourcing, and a little on a salad or steamed veggies should be fine!

  3. Janet Bell says:

    Hi Robyn, Thanks for your thoughtful comments. My husband has no thyroid (cancer 6 years ago) and takes Synthroid as thyroid replacement. He can’t do anything with iodine, so that’s out, but does it change your recommendations in terms of crucifer intake?

    1. Robyn says:

      I personally took a drug thyroid for about 8 years before I learned about bioidentical treatment. I ate tons of greens that whole time. Just because I did it doesn’t mean he shouldn’t consult a good practitioner about it. But I think at the moment it has become “conventional practice,” unquestioned, to just repeat this idea carte blanche—if you have thyroid problems, don’t eat crucifers. Seems a tragedy to me. What I’ve written hopefully gives some balance to the controversy.

  4. Thank you Robyn for writing this. It is amazing how motivated people are to find negative effects in the rare foods healthy for us to eat. I have had hypothyroid myself for a long time that I finally cured. That is true that hypothyroid is endemic, and kale consumption isn’t.
    I drink one green smoothie a day and eat green salads at every meal, and I would certainly not rule out the most fibrous green veggie of all. I wish your response was published in the New York Times.

  5. Christine says:

    Thank you for posting this! I’m a long-time fan of the NYTimes, but have noticed lately that many of their blog-style online articles are unsubstantiated opinion pieces that can be quite misleading. You did a better job of backing up your opinion as a subject matter expert with research findings. Lol – yup, our naturopath advised my hypothyroid hubby to go easy on raw cruciferous veggies. And, I’ve been handing him kelp capsules!

  6. Sheen says:

    This is not just a journalistic hoax. It’s important to have balance in your daily intake of food, including greens. Without proper guidance and a thorough understanding of your body’s individual needs you could be doing harm by overdosing on raw, cruciferous vegetables. It’s important to consult your physician or trained nutrition specialist before you make any major adjustments to your diet especially if you are on a thyroid replacement of any kind. Before you take advice from anyone do your research on the training the individual has received and determine if what they are saying feels right to you.


    1. Lauren says:

      If you have health issues that be affected by eating certain foods, then yes. Or if a person is on a medication that could be affected or altered by eating a certain type of food, then yes, I could see that.

      But honestly, the idea that we need to constantly consult doctors, nutritionists, and/or dietitians before putting healthy foods into our bodies is starting to border on ridiculous. Communities of healthy people around the world have been feeding themselves for centuries before “consulting a doctor” was ever even an option. For many even nowadays, it’s still not much of an option.

      If it happens to be a complicated issue, then I could understand that (as you mentioned with the thyroid). But we’re starting to take away the common sense and critical thinking abilities away from regular ol’ folk if we start insisting that they need to consult trained individuals for something that is as instinctual as eating. We’re turning something basic into something bordering on rocket science.

  7. Question: If you eat a lot of salty food, don’t you have a lot of iodine in your diet already? (As long as you use salt that says it supplies iodine, of course.) I’ve also heard that too much iodine can have the same effect as not enough….

    1. Katie says:

      I have been taught that the iodine they put in salt is not usable by your body and may also be toxic. I don’t have any sources to back it up, but might be worth researching. The chemically treated salt they add it too is not the best for your body either.

      1. Robyn says:

        adding synthetic iodine to refined salt is a terrible way to get our iodine—agreed, Katie!

    2. Sarah, unfortunately consuming iodine through refined iodized salt is a common misconception. Here is a great article I shared with my mom when she raised the same question. http://articles.mercola.com/sites/articles/archive/2009/10/20/Signs-Symptoms-and-Solutions-for-Poor-Thyroid-Function.aspx Hope that helps! 🙂

  8. Stuart says:

    Very well stated! Thank you!

  9. GREAT article I am so happy you addressed this!

  10. Christine says:

    I was diagnosed at 26 with Hypothyroid and at the time, I had never eaten kale. It’s a shame that these journalists write articles without really finding the time to research. Yes, I’ve been told about staying away from cruciferous foods but that has not stopped me from eating kale, broccoli, etc. Thank you for your article and setting the record straight! Love your articles and the blog!!!

  11. Janet Kent says:

    Kale in moderation is fine. I am 76 and have eaten kale all my life particularly organic, and home grown too. I have NEVER suffered ill effects from eating ANY greens but it is always wise to be moderate in all things green and rotate your greens. I am very healthy and enjoy a green smoothie every day , sometimes twice a day and am sure that this is why I enjoy good health. Always great, sensible info for which I thank you. Blessed Be.

  12. Margie says:

    Great article – posted it on my FB page!… With regards to Iodine… if one is drinking “sole” each morning, would that take care of the Iodine requirement?

  13. Judit says:

    Following a total thyroidechtomy, I have not one ounce of thyroid left in my body. I take the usual Oroxine dose (this is how they call it in Australia) and it is kind of balanced, After the initial balancing, I have no symptoms to mention. My breakfast is a smoothie with greens (this week kale), I juice vegetables usually at night. After my thyroid surgery I tried to research a more natural course of actions, but couldn’t find any natural way to go – and my doctor also assured me, that Oroxine is the best. Replacing the missing thyroid is a life-death situation and in my case at the moment Oroxine is a life-saving medicine. I wonder whether I could do better than that. I know that you are not a doctor and careful with med. advice, but you also did a lot of research and maybe found something more natural that could – if not replace, but to add to my thyroid health. There are a huge amount of literature about different thyroid problems, but not much for people who don’t have thyroid left.
    Your infos are great, I enjoy reading and in some cases following them. E.g. daily smoothie.
    Thanks for putting yourself in the frontline to improve people’s health & life.
    BTW, have you read or heard about the new Australian book ‘Mum’s not having chemo’ by Laura Bond? If not, well worth to have a look.

  14. Congratulations for your excelent articles, I have been a vegetarian for over 44 years, lived in Colombia, South America. How can I get bread or crakers without gluten, I been reading such product is bad for the digestion system, it cause me heartburn and upset stomag, how is this product add to breads crakers etc. or could the heartburn and upset stomach com from the elycobacter pilory. Green S. Girl thank you so very much for your articles and the benefits, the alert you bring to millions of people all over the earth, thank you again I apreciated a comment about gluten, have a wonderfull day Juan From Medellin, Colombia, chao girl, you are a very beautifull girl, may God bless you.

  15. Bob says:

    Correlation is not causation. This is a foundation principle of the science of statistics.

  16. Robin, I am so glad you mentioned the iodine deficiency issue in your post! An obvious (yet most assuredly overlooked) conclusion of the original journalist’s post was that IODINE DEFICIENCY is really what can lead to thyroid problems. But notice she didn’t harp on that too much – just on the kale. 😉 Thanks for a great post, and for reminding everyone that we really must read between the lines when reading and researching!

  17. Jill says:

    LOVE your blogs! I am also hypothyroid (Hashimoto’s) and I just saw a naturopath last week for help. It is comforting to know I not the only one dealing with this issue and there is hope. Thank you for sharing your wisdom, Robyn. You are a gift!

  18. Becki says:

    Hi Robyn, I have struggled with hypothyroidism for years and am currently on synthroid. Would you consider sharing with me the bio-identical hormone practitioner you use? I live in the Salt Lake area.

    1. Robyn says:

      Becki, I’ve gone to several. I don’t have one that I would necessarily recommend.

  19. Nikki says:

    Hi Robyn, A few months ago my OB found a nodule on my thyroid. I’ve since had it biopsied twice with the same results of atypical cells, inconclusive. The doctors say I need to take it out so they can biopsy the whole thing but I really don’t want to take out half my thyroid if I don’t have to. For the last six months I’ve been working with a chiropractic office (Dr. Stockwell) and their bio meridian machine to try and get my gut healthy and everything else and hopefully get rid of this nodule, but it’s still there. My blood work is normal, I’m not hypo or hyper. I’m currently doing your detox in hopes that will help too. Taking iodine along with a lot of other supplements to help speed the process, and before your detox I was on the GAPS diet for four months. I’m just wondering if you have any insight on this for me? Sometimes I just want to throw in the towel and get it taken out so I don’t have to worry but I’m concerned that will cause hormonal problems down the road for the rest of my life. I would love your opinion, I was hoping to talk to you when I went to your seminar in Bountiful but couldn’t wait for the line. 🙂

  20. quiltfarmer says:

    Hi Robyn,
    thought your response to this ridiculous journalistic clap trap was right on the money. I do disagree with you on one point, and that is that she didn’t know it would go viral. I would say as a professional (and I use the term very loosely) journalist she knew exactly what she was doing! These kind of shenanigans are how you get noticed in the journalistic world, hopefully though she wont be rewarded with a better job or even more exposure. I really think that the whole thing is really pathetic.

    I just purchased your 12 Steps program and am slowly reading and learning. Really great stuff!

  21. Mindy says:

    Hi Robyn,

    Great website! I came here looking for info on green smoothies for those of us with Hypothyroidism. Thanks for your article!

    In reading it, when you talked about taking Lugol’s, it triggered for me memory of an article that I read. You may or may not be interested. It is saying to be careful with it and sites good reasoning. Here tis – http://articles.mercola.com/sites/articles/archive/2009/10/20/signs-symptoms-and-solutions-for-poor-thyroid-function.aspx

    Thanks again for your website!

    1. Mindy says:

      Oh ya, also… this may be a dumb question, but you mentioned that 5 oz of kale several times a wk is no problem. Is it 5 oz of fresh or juiced/smoothied kale? OR…. is that weight one and the same? hee hee. It may be. I just don’t know. Thanks again!

      1. Robyn says:

        Mindy, well, I’d be way outside my purview and expertise to recommend to someone how much….but juiced kale is more than chopped, of course.

        1. Mindy says:

          Ok. Thanks for getting back to me so quickly. Appreciate that!

          In your article you said that there are a number of studies that show that the 5 oz a few times a wk has no neg impact. Can you maybe give me a study or two that I can go and look up? Would really love to read them for myself. Would be a great help to me.

          Ya, so if I took 5 oz of fresh Kale and juiced it, I wonder if I’d be getting more of the goitrogens because of it’s having been juiced and it’s concentration?? Hmmm….. dunno. That is definitely something I’d like to find out.

          A pain in the butt being Hypothyroid may I say!

          Thanks Robyn!

        2. Mindy says:

          Did find one study. Here it is – http://lpi.oregonstate.edu/mic/food-beverages/cruciferous-vegetables

          However, the 5 oz. that they are referring to are for healthy individuals and not thyroid compromised individuals if I am not mistaken.

          Still searching…

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