McCarrison Society

Health Through Nutrition, A Birthright

Iodine Deficiency a serious issue

This extract in the main came from this thread on a breast cancer support site called, which has no commercial content, acting as a forum to supply mutual support for those with an interest in breast cancer.

I R.B. am the main author of this particular thread author.

When I have time I will use incorporate some more of the information on the tread, in a more organised form with other material here.

“To try and get your interest you may not be aware:

The breast contains the second highest concentrations of iodine after the thyroid; there is increasing evidence that iodine is central to breast health, and that iodine deficiency is a significant factor in the increasing incidence of mastalgia and fibrocystic development, as well as breast cancer.

Iodine is also fundamental to brain development in utero. Neuronal development starts at around 8 weeks, so prenatal nutrition is also important.

Iodine deficienceySlide from a presentation at the RSM by R A Brown, with thanks to the authors of the cited papers.

Iodine deficiency is particularly prevalent in women, and a large number of women in the west are iodine deficient.

Traditional cultures recognised that certain foods produced healthier humans. Some traditional inland peoples to address the need for iodine burnt and ate the ash of water based plants that accumulated iodine, traded fish eggs, or marine foods, but many vulnerable groups did not, and suffered high levels of full blown goitre.

(I have since seen suggestions the highest concentration is in the ovaries; actual amount might be greater in the breasts because the quantity will depend on reproductive status and logically size); Nature being as efficient as it is, the centrality of iodine to breast function suggests iodine is important to reproductive function, breast function and health, and indeed the lactating breast concentrates iodine into breast milk because it is essential in infant development.

As well as being essential to reproduction including embryo formation, iodine is fundamental to wider body function, and for a number of reasons many people are deficient, which sounds so trite. I scream to myself with silent frustration because the consequences of iodine deficiency are so enormous, iodine is so cheap, many in the world are iodine deficient, intake levels in the west are often falling, and our intake of iodine competitors and blockers are rising.

A vast amount about the roles of this most fundamental nutrient, iodine, is unknown because in comparative terms there is little funding for research. A lack of funding interest and ‘marketing’ budgets for ‘non profitable’ treatment options (how do you define life health and wellbeing in terms of profit) is a consequence of our commercial primary imperative – you cannot patent iodine so however important it is to health there is little impetus to look at its wider roles in the body beyond the thyroid – and they are many – including very important interactions with polyunsaturated fats, and roles in cell maintenance and immune function.

There is some evidence of a link between iodine deficiency, thyroid dysfunction, breast fibrosis, and possibly cancer, and they have know about it since 1896 (See Venturi ref below), so after 100 years maybe it is time for the issue to gain some traction. The negative impact of smoking and requirement for vitamin C both took over 100 years to gain recognition as health issues, so let us hope that iodine will shortly get the focus it deserves.…ghlight=iodine

Later Addition

As this thread has developed I have become increasing aware of the relevance of substances that block the use of iodine, and so lead to enlargement of the thyroid at some level even if sub-clinical; for the purposes of these threads these iodine blocking substances are referred to as goitrogens. The breast and other tissues have iodine transporters as does the thyroid, and the iodine metabolism systems in all these tissue are one way or another affected by goitrogens.

Many food are goitrogenic including in particular brassicas and most soy products, but to add to that there are a number of human additions to the food and water chain namely perchlorate, flouride, chlorination of water, nitrates, and others such as chlorinated bi-products such as PCBs that all affect both the thyroid and wider iodine metabolism.

Bromine competes with iodine and is also added to foods and drinks in the US and is possibly used in the brewing industry including in the UK.

Fluoride it appears is produced in large quantities from the burning of coal, and it looks like and logically airborne fluoride is taken in the lungs and via plants and animals through deposition on the land via the food chain.

Higher iodine intake will to some extent balance the effect of goitrogens, but the mechanisms are complex, and some goitrogens have been shown to severely impact on thyroid mechanisms even where iodine intake is generous.

This vast increase in goitrogenic substances in our lives is a strong argument for a greater need for iodine in the diet. How much iodine we need is a hotly debated topic, but based on the large numbers of those that are showing thyroid disturbance, and surveys of iodine deficiency, it is certain that many of us are not getting even minimal amounts needed with dire long term health consequences. The iodine intake that was sufficient to prevent ill-health is logically no longer sufficient given the huge amounts of human additions of goitrogenic substances to out diet. (Absorption through the lungs from air and skin from water are also a factors).

Fluoride is one of a number of goitrogens, which focuses a spotlight on water fluoridation. The biggest problem is arguably not the fluoridation of water per se but its additive effect to the large number of high fluoride sources, and the increasing of natural levels, by human activity, which maybe were not fully appreciated when the policy was developed, including as stated above the additive related metabolic ‘blocking’ effects of chlorination, bromination, the use of nitrates, perchlorate from fertiliser and explosives, and other chlorine products such as PCBs. . Fluoride is naturally found in food and water, including in high levels in fish; but in fish it comes with iodine and calcium, whereas most land based foods contain very limited iodine. Calcium can only potentially reduce flouride uptake by some form of binding, if it is present in the gut at the same time, be that in water of food.

Importantly this…55123115,d.Yms Chinese study of a population with both high fluoride 3mg per litre (approx) and relatively high iodine 1mg per liter (approx) in their water observed In high iodine and high fluorine areas, the goiter and dental fluorosis rates of children aged from 8 to 12 were 29.8% and 72.98%. which suggests that higher iodine alone may not mitigate high fluoride intake (other factors such as minerals intake, selenium levels etc. may explain why fluoride appears more potent in some areas than others)

Does high fluoride intake in whole marine foods have the same effect is a question I raise, as we have always associated fish intake with healthy populations. Fish would also contain important minerals such as selenium and zinc as well as iodine. Fluoride apparently actively binds with selenium which may be protective against the effects of fluoride. Apparently it also bind with other minerals including calcium, so could part of the effect of fluoride be to inactivate minerals, which are often already in short supply in the western diet, but are provided in marine foods. Absorption of fluoride in fluid form is also apparently more efficient than from food, it is suggested; as ever things are multifaceted and complex.

There are particular issues around fluoride in water (natural or added – some bottled waters can contain natural fluoride as well) that is used to make up formula as it appear the breast selectively excludes significant fluoride from breast milk, and intake of floured by infants through breast milk is low. (Fluoride Alert (Link) – Infant Fluoride Exposure- video on Fluoride alert site Video Link here)

There are indication high levels of fluoride may impact brain development in utero (Link), which may suggest that effects might be seen in very young infants, so fluoride in water used to make formula may have relevance. In addition effects are likely to be moderated or amplified respectively by sufficiencies or deficiencies of iodine and minerals in breast milk.

This video on the ‘Flouridealert’ web site (link below) powerfully highlights why fluoride as a ‘goitrogen’ (iodine blocker) is a big potential issue; and whilst it deals with the thyroid, the impact of iodine deficiency is much wider including on breast tissue and formation.

However it is also fundamentally important not to lose sight of all the other things we are doing that increase iodine blocking substances in our diet, water and air.…thyroid-gland/

All in all a depressingly big Ouch ):”

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