The advice given by thyroid docs, at least the kind that understand more about it than average and are willing to prescribe Armour, etc, is that you should reduce goitrogen intake while you are first starting treatment for hypothyroidism and/or iodine deficiency, then they're OK to have more of in your diet. The goitrogenic effect of most of them is minimised or negated by cooking anyway. Mine did advise that soy could be a bit more problematic and you should avoid consuming any within four hours of taking your thyroid medication, if you swallow the medication instead of taking it sublingually.

Very interesting!  I was hoping you would follow up your iodine/goiter posts with something about goitrogens.  I'd like to read up on the human trials, if there's anything more than abstracts available.  Any urls handy?  Also, just wanted to say I really appreciate your blog, and thank you.

I have Hashimoto's thyroiditis and my endocrinologist (who is fantastic; she titrates my dose to my symptoms, and has me on Armor) has suggested that I want to take the following two precautions around goitrogens:

a) Don't eat the "biggies" such as soy within four hours of taking my thyroid medication.

b) Eat them moderately and fairly steadily; a serious pig-out on raw broccoli or edamame after weeks without may cause a swing, but a normal diet that includes them is no big deal.  This means that I actively want to include these things in my diet (which is good, because I both like them and they are good for me.)  If I keep the amount steady then we can just balance my dose against any goitrogenic effect they might have.

My understanding of the cruciferous vegetable family is that their goitrogenic effect is negated or at least minimized by cooking or fermentation.

Hi Dr Davis,

FYI - in case you are not aware, the home testing kit shopping area is not working.  At least I've tried ordering with two different computers with out luck.

Flit--

Thanks for your comments.

I like option "b", the most practical and logical.

Anon--

I believe that the lab test area should be working now.

We are in the process of transferring all files over to a new website and servers. There may therefore be momentary glitches that shouldn't last more than a few minutes while the programmers make the switch.

On the bright side, the new website will be more user-friendly.

Max--

The easiest way is to just go to PubMed.gov and enter the relevant search terms.

You will find oodles of studies, many in mice or in vitro preparations, a few in humans. You can specify which--mouse vs. human, for instance, in your choice of search terms.

The researchers claim that the findings provide little evidence that "in euthyroid, iodine-replete individuals, soy foods, or isoflavones adversely affect thyroid function."
The researchers also stated that "there remains a theoretical concern based on in vitro and animal data that in individuals with compromised thyroid function and/or whose iodine intake is marginal soy foods may increase risk of developing clinical hypothyroidism. Therefore, it is important for soy food consumers to make sure their intake of iodine is adequate." They also claim that "some evidence suggests that soy foods, by inhibiting absorption, may increase the dose of thyroid hormone required by hypothyroid patients."

This study is suggesting that soy is safe -- unless you have a thyroid condition, or iodine deficiency. It also suggests that soy foods can inhibit absorption of thyroid medication.
The study doesn't address the fact that it's estimated that as much as one-fourth of the U.S. population is now iodine deficient, and that the number is on the rise. At the same time, many millions of Americans also have undiagnosed autoimmune thyroid disease. At minimum, if you accept the premise of this study, that means that more than 75 million Americans with iodine deficiency may be at risk of thyroid problems from soy consumption. If you include the up to 60 million Americans who have a diagnosed or undiagnosed thyroid condition, almost half of all Americans could be at risk of soy-related thyroid problems.

It's also troubling to note that the author of this study -- and several other recent studies claiming soy is not a danger to the thyroid, is Mark Messina, PhD. Messina, though not a medical doctor, also goes by the name "Dr. Soy." Messina had been in charge of grant funding at the National Institutes of Health (NIH), where he oversaw a $3 million grant for soy studies. Soon after he left NIH, he was hired to serve on the scientific advisory boards of both the United Soybean Board, and international soy agribusiness Archer Daniels Midland. He still serves on both scientific advisory boards as a paid advisor. In addition to his work on these advisory boards, Messina is a consultant to the United Soybean Board and editor of its soy-related newsletter, and serves as a paid speaker and consultant to promote the positive benefits of soy for the United Soybean Board's "Soy Connection.". Messina has also published a number of books promoting soy. The "Political Friendster" website, which tracks corporate influence, has documented the close relationship between Messina and the various corporate players in the soy industry.

the full 5 page article can be read at.
http://thyroid.about.com/cs/soyinfo/a/soy.htm?nl=1

Help, I am so confused!

I have a goiter and nodules diagnosed via an ultrasound screen. I have an appt with my MD to take the next step to do lab etc. I am hoping the goiter is caused by iodine deficiency and not Hashimotos. I have been reading about supplementing with iodine but some folks say take lots (12+ mgs) others say taking more will exacerbate a hypothyroid condition. I have been taking kelp capsules 4 daily supplying 1600 mcg. I have been tempted to up the dose but don't want to mess things up. Should I wait until test results come back, then if it is negative for Hashi's go ahead and do mega doses? or should I not be afraid to supplement?

Thanks for this blog, and thanks for all the intelligent comments through-out. I have learned so much.

Laura in Arizona

Hi again Dr Davis,

I was the one that wrote earlier about having troubles ordering testing kits.  The system still is having trouble - at least with my computers, at home and work.  Thought you might want to know.  
The error occurs after pressing the submit order button.  

Below is a cut and paste of what the error says.  Hope this helps!    

Server Error in '/' Application.
Retrieving the COM class factory for component with CLSID {17B9BE57-09EA-11D5-897B-0010B5759DED} failed due to the following error: 80040154.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Runtime.InteropServices.COMException: Retrieving the COM class factory for component with CLSID {17B9BE57-09EA-11D5-897B-0010B5759DED} failed due to the following error: 80040154.

Source Error:

Line 146:
Line 147:    Public Function ProcessCC(ByVal PaymentObject As PaymentObjCC) As ArrayList
Line 148:        Dim pfpro As New PFPro
Line 149:        Dim Response As String
Line 150:        Dim pCtlx As Integer


Source File: E:inetpubwwwrootTYPTYP_MainApp_CodePayflowProPFProProcessor.vb    Line: 148

Stack Trace:

[COMException (0x80040154): Retrieving the COM class factory for component with CLSID {17B9BE57-09EA-11D5-897B-0010B5759DED} failed due to the following error: 80040154.]
   PayFlowPro.PFPro..ctor() +13
   PFProProcessor.ProcessCC(PaymentObjCC PaymentObject) in E:inetpubwwwrootTYPTYP_MainApp_CodePayflowProPFProProcessor.vb:148
   Checkout.CompleteOrderCC() in E:inetpubwwwrootTYPTYP_MainproductsCheckout.aspx.vb:970
   Checkout.btnSubmitOrder_Click(Object sender, EventArgs e) in E:inetpubwwwrootTYPTYP_MainproductsCheckout.aspx.vb:1113
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +111
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +110
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565


Version Information: Microsoft .NET Framework Version:2.0.50727.3082; ASP.NET Version:2.0.50727.3082

What a great resource!

How about humans? The few trials conducted in humans have shown little or no effect. In most instances, the adverse effects of goitrogens have been eliminated with supplemental iodine. In other words, goitrogens seem to exert their ill thyroid effects when iodine deficiency is present. Restore iodine . . . no more goitrogens (with rare exceptions).

ABOUT THE QUESRCETIN has also been identified as a goitrogen (Giuliani C et al 2008).

WOW, this is the most detailed information I have seen so far  online about the Resveratrol and flavonoids being goitrogenic,

I have been searching and searching, as I just had read briefly of an experiment with rats that showed Resveratrol (red wine + grape seeds extract) was causing the thyroid gland to enlarge
I really appreciate you posting this info

I have hypothyroidism, I take small doses of Armour and it really works great for me, and was taking Resveratrol too, (which by the way, it seemed to help me a lot, especially with giving strength and gloss to my hair)
So when i heard about this experiment i was shocked. Then I found out that even all kind of fruits are goitrogenic (as you point out) and tea and greens and garlic and onion and potatoes and beans, but above all, fruit and grapes.

Is so hopeless, I in fact, by fear, suspended the resveratrol, and now, and is funny, as now I am experiencing some minor hair loss, I am sure due to that I stopped taking this amazing supplement which was helping my hair to grow strongly

So I am so confused, my doctor as most of doctors, do not have a clue, as there is no enough info about all this and also no willingness to look into this research as well

He told me to stop taking it
But as you point out, then we should also stop eating then, as it seems that for one reason or another ,, all food is goitrogenic, soy, brassica greens, all greens, and veggies and fruit and also chickens and animals that seems are fed with goitrogenic grass and seeds
So what choice do we have?
ALSO I found this experiment on same PubMed which seems contradictory, I am not a doctor but it seems that it helps to add iodide (which is in iodine)  to the thyroid???

IS there any MD on this site who might throw some light on this???

or anyone here who has read more on this quercetin or Resveratrol? or knows about where to find more info about real evidence that flavonoids really work that way in humans????
(by the way thank you for posting the Giuliani experiment, was that on humans or rats?)

Does anyone knows of a good medical website or any that provides more information about this confusing subject?
Please, help, let me know,
Thank you
Nella

OOPS
about the QUERCETIN

here is that experiment URL
http://www.ncbi.nlm.nih.gov/pubmed/20151827

Spontaneous human Combustion is something that has always captured all my attention. Thank you for the interesting post, it's been a real pleasure reading it.

very nice psot Kamagra

Dear Dr. Davis;   thank you so much for your blog...praying you reach many people.

Is there a test for K2 deficiency? I have both osteoporosis and CAD. I have asked my doctors about vitamin K, but neither could tell me anything about it.

What is the difference between K1 and K2?

Great blog. Thank you.

Anne--
I have not yet been able to find a laboratory that makes K2 measurements available. However, it is a safe assumption that, unless you ingest fermented traditional cheeses (not Velveeta, etc.), pate or liver, or natto (blechh!), then there's an excellent chance you are deficient. To my knowledge, there is also no definition of deficiency, even if we were able to obtain a blood value. This will unfold over the next two years as data trickles out and experience accumulates.

What is a good dose for Vitamin K? Sine I'm not much of a cheese eater, or liver for that matter, I figure it can't hurt to take a supplement....but have no idea how much to take!

The problem is that there is no dose.
Based on available data, we have been advocating a dose of 1000 mcg (1 mg) per day, though the evidence is, admittedly, slim to support this specific dose. Changes are possible--probable--in future, as the experience develops.

Vitamin K test available at http://search.lef.org/cgi-src-bin/MsmGo.exe?grab_id=0&page_id=4131&query=vitamin%20k%20testing&hiword=VITAM%20VITAMER%20VITAMERS%20VITAMI%20VITAMINA%20VITAMINC%20VITAMIND%20VITAMINE%20VITAMINES%20VITAMINIC%20VITAMINK%20VITAMINS%20k%20testing%20vitamin%20

Differences between K1 & K2 also discussed at http://search.lef.org/cgi-src-bin/MsmGo.exe?grab_id=0&page_id=1152&query=VIT%20K1%20K2&hiword=K1%20K2%20VIT%20

aCCORDING TO THE ABOVE:  Tufts University tests the vitamin content of foods for the U.S. Department of Agriculture which maintains a database. Not too long ago, new technology allowed a more precise determination of the vitamin K content of food. Using the new technology, Tufts researcher Dr. Sarah Booth discovered that the vitamin K content of most foods is lower than researchers previously thought.

Green leafy vegetables supply 40-50% of vitamin K for most Americans. Vegetable oils are the next highest source. Hydrogenated oils (margarine, for example) create an unnatural form of K that may actually stop the vitamin from working.

There are three different types of vitamin K: K1 which is from plants, K2 which is made by bacteria and K3 which is synthetic. Vitamin K3 is generally regarded as toxic because it generates free radicals. This version shows promise in the treatment of cancer. K2 specifically keeps calcium and phosphorus out of the aorta, and reverses the effects of heart-unfriendly diets. The body converts K1 to K2.

Dosage and precautions

Vitamin K is not stored in the body, and is therefore nontoxic in high amounts. Forty-five milligrams a day were used in osteoporosis studies without any ill effect. Vitamin K has been approved in Japan for the treatment of osteoporosis since 1995. Several thousand times more than what people are currently getting in their diet has been taken without any toxicity. Dosage depends on an individual's diet, age, whether they are taking drugs, and what stressors are present. Generally, 10 mg/day is recommended.

If you want to get your vitamin K level tested, request the osteocalcin test. It is much more reliable than coagulation tests. The osteocalcin test measures how much carboxylated osteocalcin you have. Since carboxylation is dependent on vitamin K, this test will give you a good idea of your vitamin K status, and whether or not you're headed for osteoporosis and possibly heart disease.

An article at the Weston Price Foundation suggests that high amounts of vitamin K1 supplementation might not be correct. The author states:

These results show that our absorption of the vitamin [k1] declines as the amount we consume increases and strengthens the interpretation that we might only be able to absorb about 200 micrograms per day. [of K1 from vegtables] …

Preliminary evidence indicates that doses of 1000 micrograms per day of supplemental K1 may contribute to periodontal disease,31 suggesting that our bodies' resistance to absorbing this much K1 from vegetables may serve an important purpose.

www.westonaprice.org/basicnutrition/vitamin-k2.html

My mother-in-law is taking nattokinase for blood clot protection and disolving a clot in her caratoid retinal artery. Would taking K2 with natto kinase interfere with the clot disolving action of nattokinase?

My motherinlaw is taking nattokinase and k2 together. She had a clot in her retinal artery causing some vision loss. Would taking k2 together with nattokinase dimish of help the nattokinase effect of disolving this blood clot?

Dear Mr Davis

Iam  lately diagnosed with arterial calcification in my lower limbs. I have no diabetes, no cholestrol issues nor any kidney or blood pressure issues, yeah I do have some anxiety.

Please tell me whether taking vitamin k2 supplements would help. Also is there a test to find out if I am defecient in vitamink. What is the best supplement I can take.
Thanks

Kindest Regards
Salim Khatri

Actually, aspirin is a vitamin K antagonist. It is sort of silly to take an antagonist AND vitamin K.
Further, if aspirin effectively blocks the K from working, the aspirin is maybe preventing platelets from clumping, but preventing inappropriate calcium deposition and therefore leading (over a long time) to arteriosclerosis and therefore CVD.
Vitamin K2 is made by bacteria and found in fermented foods and animal organ meats. These are two food groups that have strong cultural ties, but they are lost as various cultures have blended into the American culture of some pretty heinous foods.
So eat sausage, sauerkraut, pickles, natto, kimchee, organ meats and avoid pasteurized of the above and this may kill the bacteria that are making the K2.

Vitamin K, on the other hand, participates in the liver production of blood clotting factors (like II, VII, IX, and X, among others for you curious ones).