Teaser Excerpt from The Paleo Approach: What about the Goitrogens in Cruciferous Veggies?

April 25, 2013 in Categories: , , , , , , , by

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The Paleo Approach by Sarah BallantyneThere are many topics that I am researching and writing about for the book that I’ve been meaning to write about for the blog for ages (the book just gives me a firm deadline). I have decided take some of these topics (especially the more blog-sized ones) and publish them as teaser excerpts for the book (also because I think this information should be here too).

This excerpt is from Chapter 6, which is the Chapter that details exactly what foods to eat to heal from autoimmune disease (think of it as a 40ish page version of my Autoimmune Protocol post.  One of the challenges I have faced as I write this book is the need to understand what recommendations are broadly applicable and what exceptions there may be for specific autoimmune diseases.  And goitrogenic veggies is a pretty hot topic given the prevalence of autoimmune thyroid diseases (and an important one to get right).

This section comes after a lengthy rationale for eating a large amount and variety of vegetables and fruits, with an emphasis on eating the rainbow and trying to eat something green with every meal.

So, forgive the references to other chapters and page numbers with no number. While you’ll have to wait until the book is out to read those sections, in the meantime, please enjoy this part of Chapter 6: The Paleo Approach–Diet

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Those with autoimmune thyroid disorders (Hashimoto’s thyroiditis or Grave’s disease) and those with low thyroid function (which can often accompany other autoimmune diseases) are often advised to avoid consumption of cruciferous vegetables, spinach, radishes, peaches and strawberries due to their goitrogenic properties.  Goitrogens are any compound that  suppress the function of the thyroid gland by interfering with iodine uptake (recall that iodine is a necessary component of thyroid hormones, see page ##).  Thyroid hormones have essential roles in metabolism and even in regulation of the immune system, so supporting optimal thyroid function in everyone is important for healing and for general health.  But avoidance of these foods is actually not well justified.

The cruciferous family of vegetables (a.k.a. brassicas) comprises many of the most antioxidant-, vitamin- and mineral-rich vegetables available, including:

  • horseradish
  • land cress
  • kale, many varieties
  • collard greens
  • Chinese broccoli (gai-lan)
  • Cabbage, many varieties
  • brussels sprout
  • kohlrabi
  • broccoli, many varieties
  • broccoflower
  • broccoli romanesco
  • cauliflower
  • wild broccoli
  • bok choy
  • Mizuna
  • Komatsuna

  • Rapini (broccoli rabe)
  • flowering cabbage
  • napa cabbage (siu choy)
  • turnip, many varieties
  • rutabaga
  • canola/rapeseed
  • mustard, many varieties
  • tatsoi
  • arugula (rocket)
  • field pepperweed
  • maca
  • garden cress
  • watercress
  • radish, many varieties
  • daikon
  • wasabi

This family of vegetables is also particularly rich in a group of sulfur-containing compounds called glucosinolates (see page ##).  When these vegetables are chopped or chewed, an enzyme called myrosinase that is also present in these plants breaks the glucosinolates apart (through hydrolysis) into a variety of biologically active compounds, many of which are potent antioxidants and are known to prevent cancer.  Two of these antioxidant, anti-cancer classes of glucosinolate hydrolysis products are also known goitrogens.  These are isothiocyanates and thiocyanates.

Isothiocyanates and thiocyanates appear to reduce thyroid function by blocking the activity of the enzyme thyroid peroxidase (a.k.a. thyroperoxidase or TPO).  During thyroid hormone synthesis, TPO is the enzyme that catalyzes the transfer of iodine to a protein called thyroglobulin to produce either T4 thyroid prohormone (a.k.a. thyroxine) or the more active T3 thyroid hormone (a.k.a. triiodotyronine).  When isothiocyanates or thiocyanates are consumed in large enough quantities, this is how they interfere with the function of the thyroid gland (by inhibiting TPO).

Importantly, the evidence linking human consumption of isothiocyanates or thiocyanates with thyroid pathologies in the absence of iodine deficiency is lacking.  This means that these substances have only been shown to interfere with thyroid function in people who are also not consuming adequate amounts of iodine (if you are severely deficient in iodine or selenium, addressing those deficiencies before consuming large amounts of cruciferous vegetables is a good idea; see page ##).  In fact, the consumption of cruciferous vegetables correlates with diverse health benefits, including reducing the risk of cancer (even thyroid cancer!).  In a recent clinical trial evaluating the safety of isothiocyanates isolated from broccoli sprouts, no adverse effects were reported (including no reported reductions in thyroid function).

Perhaps even more compelling, at low concentrations (like what you would get just by including cruciferous vegetables in your diet), thiocyanates actually stimulate T4 synthesis, meaning that consuming these vegetables labeled as goitrogens may actually support thyroid function.  There is also a strong synergy between isothiocyanates and selenium in the formation of the very important enzymes thioredoxin reductase (see page ##) and glutathione peroxidase (see page ##).  This means that the consumption of isothiocyanates in conjunction with selenium is a tremendous support for the body’s antioxidant defense mechanisms and important for cancer prevention.  These are arguments for consuming more cruciferous vegetables, even for those with autoimmune thyroid diseases, not less, especially in the context of adequate dietary iodine and selenium.

Truly, the most important aspect of supporting thyroid function is providing the necessary minerals for thyroid hormone production, the most important of which are iodine, iron, selenium and zinc.  Deficiencies in any one of the minerals may impair thyroid function, but the effect of deficiencies is greatly magnified when more than one of these minerals are not available in adequate quantities.  Iodine is a necessary building block of thyroid hormones and the thyroid cannot function properly if insufficient iodine is available (see page ##).  Iron deficiency impairs thyroid hormone synthesis by reducing activity of TPO (which is heme-dependent, see page ##).  As already discussed in Chapter 3, selenium is required both for the conversion of the T4 thyroid prohormone (a.k.a. thyroxine) to the more active T3 thyroid hormone (a.k.a. triiodotyronine) because the enzymes responsible for this conversion (iodothyronine deiodinases) are selenoproteins.  Selenium is also essential to protect the thyroid gland from the effects of excessive iodide (excessive iodine inhibits the activity of TPO).  Zinc is believed to play an important role in thyroid metabolism, although the details remain unknown.  It appears to play a role in the conversion of T4 to T3 and zinc levels correlate with the levels of thyroid stimulating hormone (TSH), although the precise ramifications of zinc deficiency for thyroid function remain controversial.  All of these minerals are richly found in the foods included in The Paleo Approach.  Supplements are also discussed in Chapter 8.

Interested in learning even more about The Paleo Approach? This video from my YouTube Channel is just a quick tour (the book is so big that giving you a broad overview takes 13 minutes!) but you get to see just how comprehensive and detailed this book is.

Barrera, L.N., et al., TrxR1 and GPx2 are potently induced by isothiocyanates and selenium, and mutually cooperate to protect Caco-2 cells against free radical-mediated cell death, Biochim Biophys Acta. 2012 Oct;1823(10):1914-24

 Bonfig, W., et al., Selenium supplementation does not decrease thyroid peroxidase antibody concentration in children and adolescents with autoimmune thyroiditis, ScientificWorldJournal. 2010 Jun 1;10:990-6

 Bosetti, C., et al., A pooled analysis of case-control studies of thyroid cancer. VII. Cruciferous and other vegetables (International), Cancer Causes Control. 2002 Oct;13(8):765-75

 Chandler, J.D. & Day, B.J., Thiocyanate: a potentially useful therapeutic agent with host defense and antioxidant properties, Biochem Pharmacol. 2012 Dec 1;84(11):1381-7

 Ertek, S., et al., Relationship between serum zinc levels, thyroid hormones and thyroid volume following successful iodine supplementation, Hormones 2010, 9(3):263-268

 Hodkinson, C.F., et al., Preliminary evidence of immune function modulation by thyroid hormones in healthy men and women aged 55-70 years, J Endocrinol. 2009 Jul;202(1):55-63

Jakubíková, J., et al., Effect of isothiocyanates on nuclear accumulation of NF-kappaB, Nrf2, and thioredoxin in caco-2 cells, J Agric Food Chem. 2006 Mar 8;54(5):1656-62

 Magnusson, R.P., et al., Mechanism of iodide-dependent catalatic activity of thyroid peroxidase and lactoperoxidase, J Biol Chem. 1984 Jan 10;259(1):197-205

 McDanell, R., et al., Chemical and biological properties of indole glucosinolates (glucobrassicins): A review, Food and Chemical Toxicology. 1988; 26(1):59-70

 Shapiro, T.A., et al., Safety, tolerance, and metabolism of broccoli sprout glucosinolates and isothiocyanates: a clinical phase I study, Nutr Cancer. 2006;55(1):53-62

 van Bakel, M.M., et al., Antioxidant and thyroid hormone status in selenium-deficient phenylketonuric and hyperphenylalaninemic patients, Am J Clin Nutr. 2000 Oct;72(4):976-81

 Virion, A., et al., Opposite effects of thiocyanate on tyrosine iodination and thyroid hormone synthesis, Eur J Biochem. 1980 Nov;112(1):1-7

 Zimmermann, M.B. & Köhrle, J., The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health, Thyroid. 2002 Oct;12(10):867-78

Comments

I Am surprised to see you mention iodine in regards to hashimotos since iodine can create a cytokines storm with hashis. Have you read the book why am I still having symptoms by dr kharrazian? He is a huge promoter of avoiding iodine. Thank you

Yes, excess iodine can cause problems (it interacts synergistically with a specific proinflammatory cytokine called interferon to enhance expression of membrane proteins in the cells of the thyroid gland that recruit inflammatory cells), BUT excess iodine is caused by selenium deficiency. Normal levels of iodine don’t do this. AND not all Hashi’s patients have high iodine. Broadly recommending the avoidance of iodine is not a good idea (and one that I don’t believe Dr. Kharrazian supports anymore). For any thyroid condition, I recommend getting your iodine levels tested and then supplementing with iodine and/or selenium as appropriate to get levels in a normal range (and I always recommend food sources of minerals over supplements if at all possible).

Thank you for the in depth explanation. I’ve always questioned the cursing of the cruciferous since I always feel better when I consume them on a regular basis. I have hashimoto’s and use iodine regularly. I feel all the better for that as well. I, however, have experienced the adverse effect of grains, sugar (excess and/or improper types) and dairy on my well being. So, while sometimes it seems like there is “nothing left to eat” when we hear “no goitrogens”, “no iodine”, “no grains, sugar and dairy”, it is important to keep in mind that we are all individuals that need a delicate balance of foods and nutrients. Some things are unquestionably harmful, others are not yet fully determined. Each person’s “balance” is so dependent on what degree of damage their body has and where their deficiencies lie. No doubt, it would be much simpler if there was a “One size fits all” approach.

very thorough and informative article. Thank you for posting it! I was wondering the same thing as Chris above…. i have hashimotos and have always heard and read and been counseled by my naturopath that if I have elavated antibodies to stay away from iodine because it will create more antibodies thus attacking my thyroid more. So for hashimotos patients do we take iodine or not?

If you have Hashi’s, get your iodine levels tested. If they are low, take iodine (food sources preferred) and if they are high, take selenium (food sources preferred). Avoiding iodine for Hashi’s as a broad recommendation is out-of-date and dangerous since those with low iodine levels will only get worse (and you can have either high or low or even normal with Hashi’s). And of course, both of those recommendations go with eating a nutrient-dense diet designed to heal the gut, resolve inflammation, and remove the over-stimulation of the immune system.

Thank you so much for these tips. Unfortunately I can’t tolerate fish or sea food. I will go back to Himalayan Rock Salt …I do have organic sea salt … is that OK?
Any suggestions for foods other than sea products and fish or should I just go with supplementation?

Read the following books:
-Hope for Hashimoto’s by Alexander Haskell (he also has videos on his website)
– Datis Kharazian – Why Do I Still Have Thyroid Symptoms? When My Lab Tests Are Normal:
-Sandra Cabot – Thyroid problem solved

Also follow the AIP to decrease inflammation.

I have hashimoto’s with TPO antibodies of 13K and am following the AIP, taking supplements to manage the diseases.

Iodine is a no no for me for now…

OMG, you’ve read my mind. I’ve been meaning to write you about this for awhile. I love you!

I’m so happy that I can eat crispy radishes w/o guilt!

I read in the Body Ecology diet that fermenting lessens the goitrogens; but recently I’ve run across comments that the opposite occurs. Is this also not a big deal?

My nutritionist told me to stay away from seaweed because it could make autoimmune disease worse, but I’ve been skeptical. Often I’m told to do what the latest advice is against my intuition only for the rules to change once again. So, I’m eating seaweed again, unless it bothers me.

I don’t have a pathological issue with my thyroid, but it’s always been suspected that it’s out of balance. My T3 is a little high, but this is opposite of most people w/ thyroid issues. I’d love to understand more about it, but it’s the least of my worries (Crohn’s disease, adrenal fatigue, congested liver & spleen, of course it’s all connected). Basically, I get information burnout; and I find myself unable to read up on things I need to know about. T1 & T2 dominance has also been on my mind a lot lately. I offer this up in case you need any book or blog ideas. ;) ;)

Thank you for sharing your investigations. It helps a lot! I can’t wait for your book.

I definitely address Th1 and Th2 dominance (and how out of date those ideas are) in the book. And good for you for listening to your intuition. I think we often have a better understanding of our bodies by instinct than we give ourselves credit for.

I can’t wait for your book! Every time you post one of these teasers I get super excited… Which I guess is the point :)

WOW I LOVED LOVED LOVED this podcast I felt like it was me talking, like you all were telling my story. I was never fat but never felt thin, I then made my self feel worthless. Thank you for this!!!

Thank you, this is so timely – was just reading about this elsewhere and getting sad about not eating many of the things on the list. And didn’t know I could get iodine tested! So looking forward to the book :-)

Thanks so much for the info, Sarah. It didn’t seem right to avoid such good veggies. Seems a lot of misinformation starts when one small fact is blown out of proportion, without looking at the big picture. It makes sense that all the nutrients work together, and that, unless you have some other deficiency, the goitrogens aren’t an issue!

Thanks for posting this again as I hadn’t seen it previously – I was on the fence about whether to eat goitrogens and this information helps me in making my decision as I tolerate them well otherwise.

I have Grave’s Disease. My symptoms seem to me to be mild (depression, tired, hair loss etc – usually associated with Hashimoto’s I thought??) I am curious about how I would understand my body’s reactions to food if I undertook the AIP? I have felt so tired for so long, will it make me feel more energetic? I’m just confused about how I will know if AIP is working for me? Any advice you can give would be greatly appreciated. Looking forward to purchasing your book. I am so grateful for your hard work and dedication.

Thanks so much for your reply. The thought of more energy and better moods is encouraging. I have felt like I’ve been dragging my feet for many years now. Getting out of bed is the hardest. I feel like I only begin to wake up at 5pm! Good luck with your book. I’m sure it will do amazingly well.

Not convinced that the benefits of goitrogen vegetables outweigh the risks if one has thyroid disease, so I will continue to avoid them. I find these vegetables stress my gut and taste harsh to me. Perhaps they just don’t work with my individual chemistry? That said, I think this is an incredible blog and I appreciate the research and time that Sarah has devoted to tailoring a Paleo diet to help people who have auto-immune issues. I am looking forward to purchasing your book!

I don’t have an autoimmune thyroid disease (that I know of anyway), but I don’t eat any of those vegetables because the whole group of them give me eczema. I am also allergic to sulfur. Do you think that the sulfur in those vegetables could be the culprit that gives me eczema? Is there a way to heal a sulfur allergy? You rock, by the way!!! I’ve preordered your book and look forward to it! But, I’m glad you are taking the time to make it just right. And, good call on splitting out the cookbook separately. I wouldn’t want you to have cut out anything to make it all fit.

Thank you for bravely traveling this unmapped trail. This is a subject I’ve been researching and your info is meaty. I’ve taken a “try it and see” approach with goitrogens and my thyroid health but found regular amounts send me into a pit of despair. Your info about selenium and zinc is helpful since synthetic T4 hormones just make me worse. My physician refuses to run even a full panel so there’s ZERO chance of getting iodine levels tested. Actually my physician refuses to write me a prescription for Armour Thyroid as well so I’m forced to get “creative” with my health care. Info like this blazes the trail for others. Thanks for your work!
Am looking forward to your book.

Can you please omit the last post and post this instead Please:

I have a hypothyroid and whenever I eat cooked or raw cabbage – especially red cabbage – I develop a hypothyroid storm. Same with taking iodine or too much seaweed. Broccoli is the equivalent of eating a potato for me in terms of insulin release. As do many vegetables which I cannot tolerate. I also have mercury poisoning from eating too much fish and it takes years of detox to get rid of it, so eating fish 3-4 times per week seems in extreme excess especially for those who have compromised detox pathways which most do who have auto-immune disease or health issues.

I went into Hashitoxicosis by eating too many cruciferous vegetables. I developed a goiter and didn’t get relief until I eliminated them from my diet. my thyroid is still off and I continue to have symptoms.

I would suggest working with a functional medicine specialist. They’ll be able to do things like tailor selenium and zinc supplementation and figure out if there are any food sensitivities, gut dysbiosis, etc. that need addressing.

Hi Sarah,
I am trying to treat my Hashimoto’s thyroiditis and came across your new book on Amazon. I underwent a total thyroidectomy due to papillary cancer in 2007 and the endocrinologist is keeping my TSH levels suppressed. Although all 3 of the endocrinologists I have seen feel that I don’t need to deal with the Hashimoto’s since I no longer have a thyroid gland, I know that the thyroidectomy did not cure my autoimmune disease. My question is whether or not I should follow the protocol for thyroid support regarding diet, iodine, zinc, selenium etc. I’ve been researching Hashimoto treatment for awhile but have not been able to find info for people who have undergone a thyroidectomy. Would appreciate your help with the confusion.

I don’t know if I have a direct answer for your question (because I don’t know the answer), but I can tell you that iodine, zinc, selenium, and iron, which are essential for thyroid function, are still essential in other parts/functions of the body. Iodine is the one I don’t know how much you would need (it is used elsewhere in the body, but thyroid is the dominant use, so maybe less than other people but still some).

my dr had me on iodine for almost a year with no tests. My Dr K trained Dr said stop.
I stopped. How long does it take it get it out of my system?

May be coincidence, but since i’ve been on iodine, i’ve not been able to maintain my weight :-( I stopped the iodine two weeks ago

I had radio active iodine done to my thyroid about 10 years ago. I had Grave’s disease and my dr couldn’t get me regulated on medication. My BP kept dropping to 90/20 or 80/40. I can only take brand name synthroid because I am so sensitive. I have noticed that if I eat a lot of curciferious foods, I start swelling and gaining weight. Last november I did green smoothies for breakfast everyday and followed Paleo without cheating and gained 10 pounds. I love eating Paleo. Any suggestions?

I understand that Brazil nuts are a good source for selenium but I thought nuts were inflammatory and to be avoided on the AIP?

I have Graeves disease but have actually put on a lot of weight. It’s driving me crazy and I generally eat really well. Any suggestions on the type of practitioner I should see to help me get the weight off? My endo has never suggested to change my diet so I find this article really interesting because I eat heaps of these vegetable!! Need help please!!!!

Sarah recommends primaldocs.com or paleophysiciansnetwork.com for finding a Paleo-friendly doc that can work with you locally or long distance. Sarah also has consultants available at thepaleomomconsulting.com. – Christina, Sarah’s assistant

Hi there! I’m wondering if the above is true for autoimmune diseases effecting your colon (UC)? About a month ago I started upping my intake of cruciferous vegetables after reading about their benefits (cabbage in particular; anti-inflammatory & cancer preventative). However, I’m constantly being scolded for eating cruciferous vegetables since they’re “hard to digest.” What are your thoughts on this?

I don’t know about the scientific evidence regarding goitrogens, however, I know of personal evidence. A friend’s mother was hypothyroid and her thryroid became enlarged. Despite the doctor prescribing more synthroid, it continued to enlarge and she was told that they would most likely have to operate and remove her thyroid. I told her about goitrogens. She included a lot of raw broccoli and other goitrogenic vegetables in her diet. Because she was desperate to avoid surgery, she decided to stop eating raw cruciferous vegetables and limited the amount of cooked cruciferous vegetables as well, supplementing them with other vegetables. A month later her thyroid had shrunk considerably. Her doctor was pleased and asked her what she did. She told the doctor about her diet change regarding cruciferous vegetables and he laughed at her and told her that was not possible. She no longer goes to that doctor. And 4 years later her thyroid is down to a normal size and the subject of surgery is long forgotten.

So I am starting the paleo lifestyle and am working my way to AIP
I’ve been getting different advice about iodine in my diet.
I have graves and it just recently got worse again
I’ve been told to avoid iodine and have been for the last 4 years now.
however recently I was told to have iodine in my diet. So I am really confuse.

For someone who has grave should they be including iodine in their diet???

thanks!

Oh I have the perfect answer to this grace of Dr Tom O’Bryan!
Had been stressing about it too. Many places in the States are iodine deficient…whilst others including the UK, where tablesalt is sometimes ‘fortified’ with iodine, furnish too much to its citizens.
So what is the answer: TESTING!!

Of course … logical! So our GP/MD’s can do a urine test. There are various tests. An iodine loading test is a high amount of iodine which unless there’s a deficiency will be passed out in the urine. The residue is measured and the amount retained is whats needed and supplementation is indicated …for a while…until optimum levels are reached…but of course our personal optimums are always changing. Hence the need for further testing until the ability to self assess is acquired.

Anyone know if there’s a blood test for iodine levels also?

Interesting Katy….I’m the other side of the coin with a low thyroid…I did get put off raw broccoli and I had been eating large amounts…with hummus – to be healthy! Ironic.

However our beloved Paleo Mom came to the rescue with the advice that iodine, iron, selenium and zinc would balance out the factors operating. I’m not exactly back on to cruciferous but don’t avoid either.

What I would like to say to encourage you Kim…is that how marvellous it is that you’ve found a way to reduce your thyroxin by ‘natural’ means!! All you have to do now is stop the cruciferous veg… re-balance…and get tested. Have your TSH, T3 and T4 measured as well as your iodine and any others levels that Sarah or her assistant might recommend.

It will then be a simple matter of juggling supplements or pref appropriate foods…to get on an even keel. How lucky you are !! Well Done.

I’m struggling with trying to stimulate my thyroid. Ideas?

hmm Interesting.
I did switch doctor and am having a appointment coming up. Will see my result and ask if there is a way to measure iodine through the blood, if not testing for me!

I have Graves and following the advice of Elaine Moore(on line help for people with Graves) I did add cruciferous veggies to my diet and had the first decrease of the Methymazole Ive been taking in 2 years, BUT I do feel a goiter. My Dr. told me to quit eating them, but now Im confused.

I had a goiter 7 years ago, was diagnosed with Hashi, told I should consider my thyroid non-functioning, and have been taking 180mg of Armour ever since. My question is this: If my thyroid is dead, and there’s no reason to believe I can improve its function, do I need to avoid or seek out certain foods based on my diagnoses? Should I question whether it’s truly non-functioning, and is there a full-proof way to tell if it has any life left? My autoantibody count has always been “greater than” the lab results can show, so I know I need to pursue a nutrient-dense diet designed to remove the over-stimulation of the immune system, I just don’t know if I should bother avoiding cruciferous vegetables as well. I’d like to start the AIP, but hoped to hear your thoughts first. Thanks so much for your amazing work!

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