Demystifying iodine: Insights for thyroid and hormonal health
with Dr Miranda Myles
Dr Miranda Myles, is director of Freyja Health, one of Melbourne ' s leading natural health and fertility clinics. She is an integrative naturopath, clinical nutritionist and acupuncturist, and founder of the Thyroid Institute of Australia. The fx Medicine podcast from which this article is adapted explores clinical prescribing and use of iodine in addressing thyroid and hormonal health. It was hosted by Emma Sutherland from fx Medicine. This article is published with the kind permission of fx Medicine.
Emma: First, to provide some context for iodine therapy: In 2003, the national iodine nutrition study measured the iodine status of Australian schoolchildren, and the results showed that they were mildly iodine deficient. In the 2011 national data set, women of child-bearing age showed the highest level of deficiency, with 18 % of women having lower than 50 microgram per litre levels, and a huge 62 % having levels below 150 microgram per litre, which is the iodine level recommended by the World Health Organisation for pregnant and breastfeeding women.
Miranda: Yes. Our thoughts about iodine need to be challenged.
Emma:. Can you explain what iodine is and what its role is in the body?
Miranda: Most of us know that quite simply iodine is the main mineral to make our thyroid hormones. It actually starts off its life as iodide in the blood, which is transported to the thyroid lumen and gets converted to iodine by an enzyme called thyroid peroxidase enzyme. And that ' s an iron-dependent enzyme.
So, our first requirement is iron, to make sure iodine is being made, so that it can be attached to tyrosine. Then one or two iodine molecules attached to a tyrosine molecule in the thyroglobulin chain, that makes T1 and T2, which then couple to make T3 and T4, which are then shunted out into the bloodstream.
I think the really important thing with this, to begin with, is that there ' s actually no circulating level of iodine in our blood. In this medium we are dealing with iodide.( Iodine itself is actually quite corrosive and can cause blistering or skin necrosis.) The only place we find iodine in the human body is within the follicles of the thyroid gland. And even here, it can be a bit of a liability if there ' s too much. So: iodine, iodide. It ' s iodide in the blood, and it gets iodised to iodine in the thyroid gland.
Emma: I think we use those words interchangeably really, don ' t we?
Miranda: Yes. And then there’ s iodate as well. But basically, iodide, iodine, iodate, they all ultimately wind up as iodide in the blood, and then as iodine in the thyroid.
Emma: And what about halogens?
Miranda: Yes, there are the other halogens: chlorine, which we find in water, fluoride, which we also find in water and toothpaste, bromine in bread, and then iodine in bread and salt. I ' ve always been taught is that those other halogens in the periodic table are all in the same line and they all displace or compete with each other. So they displace iodine. There has been recent conjecture about this, although fluoride and iodine most definitely do seem to be competing. But now there ' s some questioning over whether the amount of chloride that we ingest, or that we ' re exposed to, is enough to actually displace iodine. And I can ' t give a definitive answer to that at the moment.
84 | vol31 | no2 | JATMS