Last updated Dec 18, 2010

How much Iodine do we really need?

[More references will be added]

Dr Guy Abraham, has, on the basis of his iodine uptake and retention studies concluded that the optimal level of Iodine is far higher than presently believed (for more about this, see Iodine summary).

The required level, 12,5 mg according to the research of Dr. Abraham, is so high that the Japanese would be the only ones in the world who get enough amounts in the food to prevent Iodine deficiency. It is not proven that their high intake of Iodine is the major reason for their remarkable longevity, though it is likely that it has contributed to an important extent as Iodine is an important antioxidant. Furthermore, it has not been established that they really require so much Iodine for optimal health (including an optimal antioxidative effect). But at least it one can conclude that so high a dose seems not to be harmful. As people have attained good health and a high age in other parts of the world with lower Iodine intake, it seems a doubtful that the level indicated by Dr Abraham is what we are "designed" for.

In this article I will discuss possible factors that could have yielded misleading results. There are two major alternatives:

  1. That there was some error in the method Dr. Abraham used to find out daily Iodine requirement.
  2. That the american subjects of Dr Abraham were exposed to factors that increase Iodine requirement significantly.

The method of Dr. Abraham

The method for establishing Iodine requirement was scientifically rigorous and he used a high end technology with a more sensitive and reliable Iodine detector than commonly used. Moreover he refined the methods for establishing the state of deficiency in the body.

A strength is that Dr. Abraham used the commonly used method for estimating the Iodine status - measurement of Iodine excretion in the urine. Dr. Abraham improved it by using more sensitive Iodine detectors, which decreased measurement errors considerably. Furthermore, he developed a more reliable method for finding out the Iodine status:

He developed a standardized Iodine loading test, that measured the excretion of Iodine during 24 hours after ingestion of a high dose. When there was a deficiency, urinary Iodine was low, because a high proportion was retained, and this retention decreased stepwise at regular intake of Iodine. Along with this decrease, there were increasing signs of improved overall wellbeing with decreased brain dysfunction and various bodily symptoms including energy level, breast pain, and bowel movement. At about 90% of Iodine saturation, the improvement was no more noticeable, so Dr. Abraham put the endpoint here. To uphold Iodine saturation, Dr. Abraham found that an intake of about 12,5 mg Iodine per day was needed. Some cases were exceptionally rapid Iodine loosers and needed even higher doses.

Dr. Abraham realized that misleadingly high excretion at the load test could occur if there was a decreased ability to assimilate the Iodine. To asses assimilation, at the end of the 24-hour period, Iodine was tested in serum and saliva samples (this is an important contribution to Iodine research and treatement, as cases with low assimiliation have been overlooked so far).

To asses body saturation with Iodone, Dr. Abraham combined the percentage of the iodine load excreted in the 24-hour urine collection with the concentration in serum and saliva. When there was a high excretion but low levels in saliva, this meant that there was a low saturation because of weak assimilation. Mostly there was a low excretion and increased levels in saliva, meaning that there was a deficincy and a good assimilation.


A strength of Dr. Abraham's method is that he uses an extensively tested and generally accepted procedure for assessing Iodine deficiency. In addition, he has improved it by using high-end measurement apparatus. Furthermore, he has added tests to detect cases with inufficient Iodine uptake, thereby making the assessment more reliable than so far has been the case. His results complied well with clinical observations in the tested cases. That is, the higher bodily saturation according to his test method, the less of deficiency symptoms were experienced.

Consequently, there seems to be no obvious reason to question the valididity and reliability of his method. A replication in an independent laboratory is yet desirable.

Possible sources of error regarding the natural need

Even if the results of Dr. Abraham are correct regarding Iodine need in his subjects, this does not necessarily prove that this is the "natural" level. Perhaps there were factors in the food and environment that lead to an abnormally increased need for Iodine. If so, in reality, barring these, the "natural need" would be lower, which would allow for Iodine sufficiency in a larger part of the world.

The suggestions below are speculative attempts to find explantions why it seems that only Japanese are fully Iodine saturated. I have been looking for general factors in modern life that might affect Iodine requirement.

Factors that might cause an increased need for Iodine

1. Decreased absorption

  • Chlorine exposure. Chlorine blocks the absorption of Iodoine. The usage of chlorinated water might contribute to a reduced uptake. Showering is an important source as considerably more chlorine can be taken up through inhalation and through the skin than through drinking. Therefore, I strongly recommend the use of Shover filters designed to filter out chlorine and other harmful substances in chlorinated water.

    So drinking chlorinated water, eating food cooked in chlorinated water, and showering every day causes a chlorine exposition that might significantly affect Iodine uptake (shower filters are not widely used). If this was true for Dr. Abraham's cases, the dose required for iodine saturation in the body might perhaps have been significantly higher than if they had not been exposed to chlorine.

    2. Increased losses

    In the kidney purification occurs by filtering out blood plasma (through the glomeruli). Substances that are essential to the body, including Iodine, are then reabsorbed (in the tubuli). In kidney damage, reabsorption may be decreased. Below some common harmful factors are enumerated that may affect the kidneys.

  • Microwave exposition (from cellphone usage). Some studies have reported signs of kidney damage due to microwaves. Especially, a Turkish study on rats, simulating the exposure levels of cellphones, found extensive ultramicroscopic changes in various parts of the kidneys, both glomeruli and tubuli, which makes it conceivable that reuptake of minerals, including Iodine, might be damaged (NERGIZ1 Y, 2000). Such damage might elevate the dose required for iodine saturation.

  • Oxydative stress. Recent research has found that exposure to free radicals can disturb the function of the kidneys (reducing blood circulation by degrading nitrous oxide) (Araujo M, 2006). More importantly recent research indicates that oxidative stress causes injury to the renal tubules (Hirose M, et al 2010). Oxydative stress is very common today. Exposure to free radicals comes from polluted air, including exhaust fumes, smoking (considerably), pesticides, fried and barbecued food, certain drugs etc. Free radicals are also generated by stress, and chronic stress is very common in the US (Suurkula J, 2008). Whether kidney damage due to oxidative stress impairs Iodine reuptake is not yet known, but is not unlikely because the tubuli are affected. If true, this would elevate the dose required for iodine saturation in those who are exposed to significant levels of oxidative stress.

  • Mercury damage. Mercury is known to damage the mineral reuptake of the kidneys in high doses, and this includes iodine. There are reasons to suspect that chronic exposure to low doses of mercury might have the same effect especially as the kidney is one of the organs where merucy accumulates. Animal studies on sheep and apes with amalgam (it contains 50% merury) in the teeth have shown kidney damage from mercury with decreased tubular reuptake of inulin, though it was not investigated whether mineral reuptake was affected (Boyd ND 1991).

    However, it is well known that mercury has a non-specific damaging effects on all kinds of cells, so it seems improbable that the cells responsible for mineral reuptake would be spared in chronic exposure, unless there is some protection mechanism that neutralizes mercury in low concentrations (I have not found any evidence of such protection in the literature). I have noted that persons with amalgam have an increased tendency for magnesium deficiency, which may indicate decreased reuptake in the kidneys. Some colleagues have independently noted the same.

    Research indicates that most people in the US have increased levels of mercury in the body. A common food source is fish, with the highest amounts in large fishes (tuna, shark). Another common source is amalgam in the teeth. Compared to people without amalgam, the level in the blood is about ten times higher when one does not chew and increases to about 50 times higher when one chews food as well as chewing gums (bruxism - grinding teeth increases it likewise) and increases likewise considerably when drinking hot liquids.

    So circumstancial evidence indicate the possibility that iodine reuptake might have been damaged from mercury in Dr. Abraham cases. If true, this would have elevated the dose required for iodine saturation.


    Although there is too little knowledge about their significance, we can at least conclude that factors exist that perhaps might affect the Iodine requirement in the cases Dr. Abraham studied.

    If so, this might explain why the requirement is remarkably high according to Dr. Abraham.

    Perhaps there are other general factors in the food or environment in the US, yet unknown, that increase the requirement for Iodine to a considerable extent. For example, there is a very large number of chemical food additives, whose health effects have not been properly investigated. The same goes for the substances that appear through the reaction of chlorine with bacteria and other organic matter when drinking water is chlorinated. Some of these compounds are already known to be toxic or carcinogenic. There are common insecticides and pesticides that are kidney-damaging, and they are ingested by most people unless they eat organic. Recent evidence indicate that when two pesticides are combined, a synergy may occur that enhances their harmful effect considerably. Often there is a combination of more than two pesticides in food.

    It would be valuable if people who have not been exposed to above mentioned factors were tested for Iodine requirement with the method of Dr. Abraham. That is, some indigenous people living in a region not "infested" with all the artificial factors of modern civilization. (Why not start with Okinawans living on traditional food after a period of reduced intake of Iodine rich components? See footnote 1).

    Overall conclusion

    There seems to be no obvious reason to question the method Dr. Abraham used, especially as it was a refinement of the well tested standard method used world-wide for detecting Iodine deficiency.

    On the other hand, there exists a number of factors that might perhaps have increased the Iodine requirement in his subjects, though it is not yet proven that they do so.

    In conclusion, the cause for a remarkably high iodine requirement lies more probably in conditions that increase Iodine losses or block absorption or assimilation than in measurement errors.

    This would mean that we are designed for a lower Iodine requirement than Abraham found. But if you live in a modern "chemicalized" soicety, you need more Iodine.

    Considering that Iodine has no harmful effects, and that 12,5 mg Iodine per day corresponds to the level in traditional Japanese food that is compatible with an unusually high longevity, it seems reasonable not to hesitate about an intake of that order of magnitude. Ideally, this should be taken as natural foods, but this is difficult for vegetarians, as a major source of Iodine is fish and shellfish (also in Japanese food, that however also uses iodine-rich seaweed.)

    Jaan Suurküla, M.D.


    I sent this article to Dr. Abraham and he agreed that there might be factors in modern life that could increase the Iodine requirement. He also agreed that it would be valuable to reproduce his findings in populations known to be in a low stress and low toxin environment.

    Interestingly, he also stated: "The level of mental and physical wellbeing is highest in subjects on 50mg iodine/iodide per day. They volunteer the information that if they decrease their intake to 12.5mg/day after they reach sufficiency*, they are not as energetic, productive and alert. "

    *) Dr Abraham uses the word "sufficiency" to denote the state with sufficient Iodine in the body to produce optimal wellbeing.


    • Boyd ND, Benediktsoon H, Vimy MJ, et al. 1991 "Mercury from dental "silver" tooth fillings impairs sheep kidney function." Am J Physiol 1991;261:R1010-R1014.
    • Araujo M, Welch WJ. 2006. "Oxidative stress and nitric oxide in kidney function.".Curr Opin Nephrol Hypertens. 2006 Jan;15(1):72-7.
    • Hirose M, et al, 2010. "Renal tubular epithelial cell injury and oxidative stress induce calcium oxalate crystal formation in mouse kidney". International Journal of Urology, 17:83-92. (January 2010)
    • NERGIZ1 Y, et al 2000. "Effect of Low-Intensity Microwave Radiation on Rat Kidney: An Ultrastructural Study" Turk J Med Sci 30 (2000) 223–227
    • Suurkula, J, 2008. "Chronic stress is highly prevalent"
    • Footnotes

      1. The Okinawans have the highest percentage of centenarians in the world and the lowest death rates from cancer, heart diseases and stroke. They are notably vital at high age and have a much shorter period of decrepitude before death than commonly. See The Okinawa centenarian study.


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