Iodine deficiency ! - falling intakes - goitregens - competition bromine and fluorine

[R.B.]

Iodine overload - how much is too much ?

Whilst there appears to be significant amount of material suggesting benefits in some from high iodine intake, possibly in those where there has been historic imbalance, or deficiency, and suggestions that some populations have a high intake, there are equally indications that high iodine intake can have adverse consequences.

Daily recommended intakes are in micro grams rather than milligrams. Is this enough given uncertainties as to the level of iodine blockers and competitors such as bromine in our diet. Clearly some think not, and sadly it appears that many are not even getting the minimum requirements in their diet, and that is before the potential blocking of iodine uptake may inhibit their usage of an already very low intake. http://lpi.oregonstate.edu/infocenter/minerals/iodine/

There is much we do not know, for example exactly how other dietary factors interact with iodine intake. The Japanese whatever their historic intake was got their intake from natural food based sources mainly seaweed which would also have been mineral rich and interestingly likely contained significant amounts of bromine (seaweed contains quite high levels of bromine generally).

Iodine contents of seaweeds vary considerably, and iodine is lost in processing and drying, which makes iodine intake through seaweed a bit of a lottery, and clearly if somebody has a lot of bromine in their system from artificially brominated foods then intuitively a food source potentially rich in bromide may not be ideal (although it is possible some of the bromine will also be lost in processing)

Bromine in foods is more of a problem in the US than UK due to brominated soft drinks and flour; but bromine may be used in other products viz the fumigation of dried foods such as nuts; nuts contain quite high amounts of bromine it appears. It seems potentially lots of foods are fumigated with bromine. Whilst there may be some restriction on fumigation with bromine in the west with foods being sourced all round the world and complex regulations I suspect sadly the reality is overall we do not know what our food contains.

I have no idea if the relatively high levels of bromine found in nut products is from the soil or fumigation, but would guess it is probably largely from fumigation in the county of origin.

Also as previously mentioned bromine/bromide may be used in the brewing industry. Does it reach the beer; I have not been able to find a definitive answer to the question.

http://www.fao.org/docrep/x5042e/x5042e08.htm "Almost invariably, nuts and shelled nuts are fumigated in the country of origin before export, often with methyl bromide. If more than one fumigation is required after importation, there may be danger of taint and a trial treatment should be made."

Methyl bromide may be particularly well absorbed because it is in an organic form (and differently ? metabolised) - oh dear that raises a whole heap of new questions - as ever things are rarely straight forward - it appears marine organisms produce it and some will end up in the atmosphere. Some plants including the brassicas produce it in small quantities. Large amounts can kill you and do kill customs officers opening containers. http://en.wikipedia.org/wiki/Bromomethane What effect does the sort of levels found in food have? I have no idea but clearly based on the forgoing a bromine iodine imbalance in the metabolic pathways is a potential health issue.

Back to iodine intake; a Japanese Radiological society paper suggest current intake of iodine was around 1mg with their parents consuming more, but exactly how much we do not know. Higher intakes may be problematic particularly for those with other dietary deficiencies including selenium and other minerals.

The paper below looked at a group of Peace Corp staff who had high iodine intake possibly 50mg a day or more for 32 months. The core conclusion is that those using iodination to decontaminate water need regular medical checks. Interestingly the paper does not recommend that sanitisation of water with iodine should not be used, only that regular checks should take place and particular care should be taken in pregnancy. It is a shame the information is not more comprehensive, and does not look at any longer term implications of high dose iodine intake if any.


Effects of Chronic Iodine Excess in a Cohort of Long-Term American Workers in West Africa

http://jcem.endojournals.org/content/87/12/5499.long

The body of the text contains the following comment; if it means this was the result of examination prior to iodine exposure it adds a further dimension to the results.

There was a high prevalence of goiter among Peace Corps volunteers in this study at baseline in both euthyroid and hypothyroid individuals. . .

Abstracts from text

As the arid climate in Niger results in the daily consumption of 5–9 liters water, the volunteers consumed at least 50 mg iodine daily, which is approximately 300 times the daily U.S. Recommended Dietary Allowance (2). Urinary iodine excretion in this iodine-enriched population ranged from 392–153,780 μg/liter (median, 5,048 μg/liter). Volunteers used the water purification devices described above for up to 32 months.

The findings in this study have significant public health implications. In 1998, an estimated 60,000 iodine resin devices and 300,000 bottles of iodine tablets were sold to U.S. civilians for water disinfection (24). In addition, iodine-based water purification systems are routinely used by the military, in international relief efforts, and by other government-sponsored programs. In this regard we have recently reported that excess iodine ingestion by American astronauts from water treated with iodine for purification in space resulted in a small transient rise in serum TSH values upon return to earth (25). Since 1998, the iodine has been removed from astronauts’ potable water by an anion exchange resin just before the water is consumed, and no rise in serum TSH values has been observed. It is probably inadvisable for pregnant women, individuals with a history or a strong family history of thyroid disease, especially autoimmune thyroid disease, or individuals residing in areas of endemic iodine deficiency to use iodine-based methods of water purification unless extremely careful monitoring of the iodine content is carried out. Any individual anticipating prolonged ingestion of excess amounts of iodine in medications or as a byproduct of a water purification system should see a physician for a baseline physical exam to exclude the presence of preexisting goiter and to measure thyroid function tests and serum thyroid antibody levels to rule out abnormalities. Repeat thyroid function tests should then be repeated at intervals until excess iodine ingestion is eliminated.

[R.B.]

This is an interesting paper on estimated Japanese iodine intake which ties in with another report I have seen.

"By combining information from dietary records, food surveys, urine iodine analysis (both spot and 24-hour samples) and seaweed iodine content, we estimate that the Japanese iodine intake--largely from seaweeds--averages 1,000-3,000 μg/day (1-3 mg/day)."
See below

The report also recognises that pre 1950 Japanese ate a lot more kelp (Kombu) "elders ate up to four times more than those under the age of 29" so their intake figures could have been significantly higher.

It is also recognised in the paper that intakes of iodine will vary considerably on a day to day basis, which is reflected in urine output. So on some days Japanese may be consuming many grams of iodine. "Urine iodine levels can increase from 100 μg/L to 30,000 μg/L in a single day and return to 100 μg/L within a couple of days, depending on seaweed intake [39]. This is somewhat expected when varying amounts and types of seaweeds are consumed on a day-to-day basis."

An analysis of studies of iodine in urine incontrovertibly shows the Japanese have much higher iodine levels than we do in the west, the data in the paper shows at least historically they had a much lower level of many western medical conditions.

It is also clear from the report that a variety of dietary seaweeds are very much part of the Japanese life, and that the seaweeds in food vary in iodine content for a wide variety of reasons.

The full paper is free and the implications are thought provoking, both in terms of recommended western daily recommended intake, and the use of iodine at higher intakes as a medicine to correct historic imbalances.


"Japanese health statistics linked to high seaweed intake

The Japanese are considered one of the world's longest living people, with an extraordinarily low rate of certain types of cancer. A major dietary difference that sets Japan apart from other countries is high iodine intake, with seaweeds the most common source. Here are some astonishing Japanese health statistics, which are possibly related to their high seaweed consumption and iodine intake:

-Japanese average life expectancy (83 years) is five years longer than US average life expectancy (78 years) [41].

-In 1999 the age-adjusted breast cancer mortality rate was three times higher in the US than in Japan [42].

-Ten years after arriving in the US (in 1991), the breast cancer incidence rate of immigrants from Japan increased from 20 per 100,000 to 30 per 100,000 [43].

-In 2002 the age-adjusted rate of prostate cancer in Japan was 12.6 per 100,000, while the US rate was almost ten times as high [44].

-Heart related deaths in men and women aged 35-74 years are much higher in the US (1,415 per 100,000) as they are in Japan (897 per 100,000) [45].

-In 2004, infant deaths were over twice as high in the US (6.8 per 1,000) as they were in Japan (2.8 per 1,000) [46]."


http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3204293/


Assessment of Japanese iodine intake based on seaweed consumption in Japan: A literature-based analysis

Abstract

Japanese iodine intake from edible seaweeds is amongst the highest in the world. Predicting the type and amount of seaweed the Japanese consume is difficult due to day-to-day meal variation and dietary differences between generations and regions. In addition, iodine content varies considerably between seaweed species, with cooking and/or processing having an influence on iodine content. Due to all these factors, researchers frequently overestimate, or underestimate, Japanese iodine intake from seaweeds, which results in misleading and potentially dangerous diet and supplementation recommendations for people aiming to achieve the same health benefits seen by the Japanese. By combining information from dietary records, food surveys, urine iodine analysis (both spot and 24-hour samples) and seaweed iodine content, we estimate that the Japanese iodine intake--largely from seaweeds--averages 1,000-3,000 μg/day (1-3 mg/day).

[R.B.]

There is regular mention in literature on iodine of endemic coastal goitre in areas of high seaweed consumption.

I have finally found a paper, as against mentions of the issue. The paper is titled

ENDEMIC COAST GOITRE IN HOKKAIDO, JAPAN
By
Hoji Suzuki, Tadashi Higuchi, Kunio Sawa,
Sachiya Ohtaki and Yoshihiko Horiuchi.

The full version of the paper includes a photo of a patient with an 'enormous' goitre; this was a real and serious issue. Urinary excretion of over 20mg a day of iodine was seen in five patients. Kelp collection was a local industry, and it formed a significant part of the diet. As discussed kelp often contains large amounts of iodine.

Interestingly when they were taken into hospital and put on a low thyroid diet some patients had a regression of their goitre.

The paper seems to suggest that iodine was actively being taken up by the thyroid, so uptake by the transporters was not the issue.

But 74.5% responded to thyroid treatment - so it looks as if something was blocking the activity of the thyroid; the thought occurred was that too much iodine as is generally suggested or something else . . .

All of which raises some important questions as to high iodine supplementation protocols, especially when reports of negative effects of high intake of iodine are limited in number. Are the negative effects of high iodine under reported or was the goitre in this instance due to to other factors? Does high iodine lead to serious thyroid dysfunction and goitre. These are very fundamental questions.

The answer to this question may lie in the unexamined issue that Hokkaido is an island with active 'volcanic' activity, and it is reported that the fumaroles are a source of both significant fluoride emissions, and fluoride deposits. Were the local water supplies, or supplies / wells / springs of individual patients high in fluorine, whereas in contrast was the hospital on a different supply?

A paper cited earlier in this thread suggests that relatively modest amounts of fouride even in the presence of iodine at 1mg/l in the water can cause fluorosis and goitre.


The Island of Hokkaido is listed as a high fluoride area (viz over 1.5mg/l), in a report called;

Fluoride in groundwater:
Probability of occurrence of excessive concentration on global scale


which cites this paper looking at volcanic fumerole activity on Hokkaido (one the most active regions in Japan) which says interalia


Acid alteration in the fumarolic environment of Usu volcano,
Hokkaido, Japan
F. Africano*, A. Bernard

The fumarolic environment studied is very rich in
fluorine. Whole rock fluorine contents range from 1 to
5 wt%. Aluminum fluorides, which are rare in nature,
are commonly observed in this fumarolic environment.
In the presence of fluorine and in acidic conditions,
the dominant aqueous Al species are fluoride
complexes, even in the presence of significant
amounts of sulfates in solution. Fluorine enrichment
in the altered silicates and in silica incrustations indicates
that fluorine plays an important role in the alteration
of the primary minerals and in the mobilization of
silica into the aqueous phase.

I surmise this could lead to high amounts of fluoride in water, which might be localised. Interestingly I could not find anything on flourosis and Hokkaido. Is or was fluorosis a problem in Hokkaido?

A combination of a diet high in marine products and volcanic activity would suggest a better than average mineral intake. I wonder if high mineral availability is protective against fluorosis.

There is no information about selenium, and apparently kelp whilst containing some selenium is not a good source, but apparently volcanoes are a significant source of selenium

It appears that goitre is not seen in all coastal Japanese communities, which would add further weight to the possibility the high fluoride rather than iodine was responsible for the goitre.

This appears to be a community that ate marine foods, seaweed, was in area that was likely to be well mineralised, probably had adequate selenium intake, and yet there was a high level of goitre. Volcanic areas are often associated with goitre so could fluoride be the cause even in a generally well nourished community. Might there be other possible contributory factors.

Might mercury have had a contributory role in the goitre incidence? Mercury poisoning in cattle in 1955 from seed treated with mercury fungicide. http://ci.nii.ac.jp/naid/110001075913 The goitre paper was written in 1965. Cranes local to Hokkaido were severely mercury contaminated. http://www.ncbi.nlm.nih.gov/pubmed/17713219Mercury Mercury deposits are found under northeastern Hokkaido.http://www.japantimes.co.jp/news/200.../#.UnV7t1N2FPI http://www.ncbi.nlm.nih.gov/pubmed/17713219 Mercury contamination of seafood in Japan reported as being at worrying levels.http://www.opsociety.org/issues/mercury-in-seafood Fumaroles may be a source of some mercury. Mercury contamination has been linked with thyroid dysfunction.

All of which raises very many questions, and most worrying of all, is fluoride sufficiently active in certain as yet unquantified circumstances to override even the effects of relatively high intakes of iodine ?

[R.B.]

More on the debate as to the requirements of humans for iodine; a paper I have just come across by Abraham whose later writing tends to be acerbic. He appears frustrated at the unwillingness of the wider medical establishment to engage with / consider the issue of iodine, and understandably so if he is right. Indeed the evidence increasingly seems to point to a greater need for iodine than is recognised in current dietary guidelines. Deficits will be exacerbated by the increasing impact of iodine blockers. The varied evidence of Japanese intake all points to intakes greater than 1mg a day and probably higher; the health of the Japanese would suggest that such intake levels are not inherently harmful and may confer significant health benefits.

I am aware that the UK advisory body is currently considering the issue of iodine intake.

It is interesting that the paper reports higher thyroid volumes in Ireland and Germany.

It is also interesting that Switzerland apparently adopted a doses of 3mg.

Some of the historical references are fascinating


Effect of daily ingestion of a tablet containing 5 mg iodine and 7.5 mg iodide as the potassium salt, for a period of 3 months, on the results of thyroid function tests and thyroid volume by ultrasonometry in ten euthyroid Caucasian women.

Guy E. Abraham M.D., Jorge D. Flechas M.D., and John C. Hakala R. Ph.

http://cypress.he.net/~bigmacnc/drflechas/IOD1.htm

"Considering the importance of this element for overall well-being, it is most amazing that no study so far has attempted to answer the very important question: What is the optimal amount of daily I intake that will result in the greatest levels of mental and physical well-being in the majority of a population with a minimum of negative effects?"

[R.B.]

This is a particularity interesting 1955 ! paper where the authors have clearly grappled with the issue of the interaction of flouride and iodine, and as to whether adequate iodine will overcome excess fluoride, when considering thyroid function. They were clearly well ahead of their time.

They starkly conclude that iodine will not negate the inhibiting effects of high fluoride on thyroid function.

They also emphasise the importance of other inhibitors of iodine metabolism.

It is somewhat ironic that this observation was made over 50 years ago.



The Relationship Between Fluoride Exposure & Goitre in South Africa - March 1955

http://fluoridealert.org/studies/steyn-1955/

Abstract - several pages of excerpts from the paper are cited

"Prophylaxis and Treatment of Simple Goitre. – It is generally accepted that man’s physiological requirements of iodine is approximately 2.0 ug. per kilogram per day, i.e. if man daily ingests this amount of iodine there should be no significant enlargement of the thyroid gland. However, recent researches into the problem of thyroid enlargement have revealed to us various interesting and important factors upon which the normal function and size of this gland depend. These factors have been discussed under III and VIII B. It has become obvious that we cannot lay down a single definite figure for man’s daily iodine requirement as it depends upon various factors, e.g. goitrogenic foods, goitrogens in the drinking water, goitrogenic medicines, bacterial infections, and vitamin deficiencies. Fortunately, as a general rule simple goitre, irrespective of the cause, can be very, or fairly, satisfactorily combated by an adequate increase in man’s daily iodine intake, except when the enlargement of the gland is due to the ingestion of excessive amounts of fluorine, as happens in areas where the subterranean waters are heavily contaminated with this halogen. The only correct solution to fluorine-induced endemic goitre is the removal of this element from the drinking water. Also from the point of view of general health this is the correct procedure…"

[R.B.]

Widespread iodine deficiency in breast milk in the US ?

It is often suggested in material that iodine status in the US is better than the UK; I have not looked for data so have no data to back this up. The above figures from the Avon study would suggest levels of iodine in breast milk are also likely to be low in the UK

Temporal Patterns in Perchlorate, Thiocyanate, and Iodide Excretion in Human Milk

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1817678/

"Breast milk–iodine content is considered sufficient when levels are 150–180 μg/L (Delange 2004). Milk samples provided by most women in our previous study (Kirk et al. 2005) fell far short of this standard. The median iodide level in human milk from 23 donors residing in 15 different states (Kirk et al. 2005) was 33.5 μg/L, and only 4 samples fell within the recommended level. We have therefore been concerned that lactating women in the United States may not be consuming sufficient iodine to meet the needs of their breast-fed infants."

The paper also expresses concerns about the effect of perchlorate on the iodine content of breast milk and the potential effect of perchlorate in breast milk. The paper observes that little is know about the issues.

It appears that perchlorate on a unit weight basis is a comparatively powerful competitive inhibitor of iodine uptake; the effect will depend on the amount taken up - so other blocking factors by be more important if and when present in much greater quantity eg food goitrogens - the effect will also depend on the amount of iodine in the diet; the lower the amount the great susceptibility to competitive blockers - fluoride appears to work by a different blocking mechanism (see above).

"Exposure to perchlorate and other iodide transport inhibitors may increase the risk of iodine deficiency among infants. The sodium–iodide symporter (NIS) is 30-fold more selective for perchlorate than for iodide and is reportedly 9–100 times as potent as thiocyanate in inhibiting iodide uptake (Dohan et al. 2003; Tonacchera et al. 2004). Perchlorate and other iodide transport inhibitors such as thiocyanate thus likely reduce transfer of iodide to breast milk at the mammary NIS."

[R.B.]

The above paper references this paper, which provides further information on the iodine requirements to preterm babies. Have formulas been updated; I do not know but this abstract highlights the importance of iodine in preterm infants


http://www.ncbi.nlm.nih.gov/pubmed/16398457

J Pediatr Endocrinol Metab. 2005 Dec;18 Suppl 1:1257-64.
Neonatal iodine deficiency: clinical aspects.
Ares S, Quero J, Morreale de Escobar G.
Source

Neonatology Unit, University Hospital La Paz, Paseo de la Castellana 261, 28046 Madrid, Spain sares.gapm05@salud.madrid.org
Abstract

Iodine is a trace element which is essential for the synthesis of thyroid hormones. The thyroid hormones, thyroxine (T4) and 3,5,3'-triiodothyronine (T3), are necessary for adequate growth and development throughout fetal and extrauterine life. The iodine intake of newborns is entirely dependent on the iodine content of breast milk and the formula preparations used to feed them. An inadequate iodine supply might be especially dangerous in the case of premature babies. The minimum recommended dietary allowance (RDA) for different age groups has recently been revised. The iodine intake required is at least 15 microg/kg/day in full-term infants and 30 microg/kg/day in preterms. The iodine content of many evaluated preparations for feeding premature infants appears to be inadequate. Premature infants are now in a situation of iodine deficiency, precisely at a stage of psychomotor and neural development which is extremely sensitive to alterations of thyroid function.