I’m only human & there are some questions that do make me silently groan & invisibly (I hope!) roll my eyes.  One is the old chestnut:  “but the Japanese consume on average 7mg of iodine a day!” which is typically offered up as a rationale for the need for mega dosing of iodine in everyone.  This is of course only a partial truth & the missing bits make all the difference!  The Japanese have some of the highest rates of thyroid disease in the world & this is in part, attributed to their high iodine exposure.  Secondly, it’s simplistic & flawed to isolate one characteristic of a whole diet & not appreciate that its effect or impact is mitigated by the context of the entire diet & lifestyle of that population.  In the case of the Japanese, for example, this includes relatively intake of isoflavones, key goitrogens which will reduce the bioavailability of the iodine both within the gut & at the thyroid. Harrumph!  I love iodine & am frequently suspicious of a deficiency in my clients, however, like many nutrients feel that our ultimate objective is for optimal nutrition…not excessive.

Am I just a conservative scaredy cat perpetuating fear around this topic in the industry?  Well…..no.  There is accumulating international evidence of big spikes in autoimmune thyroid disease diagnoses following the introduction of iodine fortification programs in previously iodine deficient countries such as Greece, Turkey & Brazil.  There is of course evidence as well that iodine supplementation in Grave’s & Hashimoto’s disease can lead to delayed recovery or worsening of the condition.

To boot, I had an up close & personal experience of this with one of my own clients this year, whom I had started on a small dose of iodine for suboptimal thyroid function.  Said patient, feeling good on the small dose gets excited on hearing about apparent ‘successes with mega doses’ & steps her intake up to 12.5mg per day without my knowledge.  One to two months in – her whole health is falling apart, she’s lost the gains she’d made with her health & her actual thyroid results??? Well they need to be seen to be believed – yet when I look at them in detail they’re a textbook example of what we’ve been told about iodine excess! She stopped all iodine 6 months ago & her thyroid function has still not completely normalised but is on its way 🙂

No knowledge is quite as impacting & memorable as that we see for ourselves firsthand in clinic & I am grateful to have learnt so much from this client & for this confirmation that it’s all about individualised nutrition & that ‘one size fits all’ hyperbole & protocols often get our clients in trouble!


I’ve recorded a 30 minute review on recognising iodine excess (it’s more common than you think!) & specifically the case study described above and another PPT case which you can download here  https://rachelarthur.com.au/product/premium-audio-iodine-excess-in-action/

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