I will review a collection of research papers written by Guy Abraham (mainly), several of them with David Browstein, Jorge Flechas, John Hakala, individually and in different combinations, one paper with Nicholas Calvino, and another with Roxane Handal. They were published in The Original Internist between 2002 and 2008.

These papers form the backbone of the science and clinical evidence that has brought about the resurgence of the therapeutic use of iodine in natural medicine, and together with it, tremendous benefits to thousands of people who have recovered their health from supplemental iodine. I will, in the process, probably review some of the papers that are referenced. My intention is to present a detailed summary of each one of these papers as a series that we’ll call The Iodine Papers. This is the first:

Levels of Iodine for Greatest Mental and Physical Health  by Guy E. Abraham, MD, Jorge D. Flechas, MD, and John C. Hakala, RPh

The question posed by the authors is a simple one:  what are optimal levels of iodine for overall health. But seeking the answer in the published literature, they discovered that there wasn’t one. This paper has three logical parts. The first is a long introduction that includes a review of several historical studies in which they seek to find clues as to what would be the optimum amount to take on a daily basis; optimal meaning not too little, and not too much. The second part is the presentation of the results of a three-month study they did on ten American Caucasian women taking supplemental iodine. And the third is the discussion and conclusions, that naturally includes their proposal for what constitutes the optimal amount of iodine we should have daily.

For those (like you M) who are not interested in the details, but just in the answer, in this case it’s 12.5 mg per day, in the form of 5 mg of iodine and 7.5 mg of potassium iodide because the two different forms are needed by different tissues. For those of you who are interested, I’ll present the contents of the paper in the structure outlined in the previous paragraph.

Introduction and previous studies

In a 1998 editorial in the Journal of Clinical Endocrinology and Metabolism entitled What’s happening to our iodine?, it is stated that one third of the world live in iodine-deficient areas, and that iodine-deficiency is the leading cause of intellectual deficiency (mental retardation).

The earliest studies that are reported are from the 1920’s, one by Marine in Ohio, and one by Klinger before him in Switzerland. Klinger’s was performed in an area of the country that had, at the time, an 82–95% incidence of goitre in its population. Goitre is an enlargement of the thyroid gland due to iodine deficiency. Obviously a very serious problem. The study comprised 760 teenagers, of which 90% (684) had goitre. They received between 10 and 20 mg of iodine per week, which equated to an average of 1.4 to 2 mg/day. Fifteen months later, none had experienced adverse effects of any kind, 472 (69%) had recovered, but 212 (28%) still had an enlarged thyroid. The government therefore opted for a slightly higher dose, advising supplementation with 3–5 mg of iodine per day.

Marine did his study in Akron, Ohio, where the incidence of thyroid enlargement was not as high, but still 56%. Goitre appeared most often in puberty and six times more often in girls than in boys, and six times more often means 600% more. That’s a huge difference. They therefore used only girls. This study was much larger, and everyone started the programme with no signs of thyroid enlargement. 2190 received iodine supplementation, and 2304 were used as controls and didn’t get any.

The programme ran for 2.5 years, with 5 periods of supplementation, one in the spring and one in the fall, in which the participants were given 200 mg of sodium iodide per day for 10 days. If we calculate a daily average out of those total of 4 grammes per year, it gives 11 mg of sodium iodide, and thus something like 8 mg of iodine. At the end of the 2.5 years, 495 out of 2304 (that’s 22%) in the control group had developed goitre, compared to only 5 out of 2190 (that’s 0.2%) in the supplementation group.

In 1966, two Russian scientists hypothesised that pathologies of the breasts in women could be caused by excess oestrogen from ovarian cysts due to insufficient iodine. They took 200 patients with what they called “dyshormonal hyperplasia of the mammary glands”, and gave them 10–20 mg of potassium iodide per day for periods that varied between six months and three years. Within three months a majority experienced significant improvements with decrease in pain, swelling and nodularity. In the 167 who completed the programme, 72% experienced significant improvements. Five patients who had ovarian cysts saw them reduce in numbers and size.

Then in 1976, a group of Canadian researchers led by Ghent, extended this study on women with breast disease, and tried different forms of iodine supplements in different amounts on three different groups. They had 233 women on 30–60 mg/day from a 5% Lugol’s solution for 2 years, 588 women on 10 mg from iodine caseinate for 5 years, and 1365 on 3–6 mg/day from saturated aqueous iodine solution for 1.5 years.

Clinical improvement—both subjective in terms of pain, swelling, discomfort; and objective in terms of reduced fibres and nodules—were seen and measured in all three groups, but with different success rates:  74% in the group using the saturated aqueous iodine solution (3–6 mg/day), 70% in the Lugol group, and 40% in the iodine caseinate group. Moreover, different numbers of women reported adverse effects from the supplementation: 11% in the aqueous iodine group, 7% in the Lugol, and 9.5% in the caseinate group.

Notably, the authors reported on the results of autopsies performed in 1928 and in 1973. Evidence for fibrocystic disease of the breast (FDB) was present in 3% of women in 1928. In 1973, FDB was present in 89% of women. That’s 9 out of 10 women back in 1973. Do you think the magnitude of the problem has decreased since? Not likely.

In Japan, Nagasaki and colleagues published in 1967 the results of their investigation of the relationship between iodine consumption and disorders of the thyroid and breasts. They surveyed different regions, some mainland and some coastal, and found an average daily consumption of seaweed of 4.6 g in mainland areas, which translated into 13.8 mg of combined iodine and iodide. Inhabitants of coastal areas had an even higher daily consumption of iodine. Investigation into the function of the thyroid supplied iodine in the amounts ingested in coastal areas showed that it absorbs more than it secretes as T3 (triiodothyronine) and T4 (thyroxine) whose levels remain in a narrow physiological range, and that the rest, the amount unused in making T3 and T4, is secreted as inorganic iodine, presumably to be available in that form to other tissues. The reason why this was an important study is that Japanese women consuming this amount of iodine, have very low rates of thyroid and breast disorders.

Finally, maybe as a remnant and reminder of the importance of iodine in medicine up to our current era of drug-based medicine, the authors make note of the fact that in the 1995 version of the standard reference Remington’s Science and Practice of Pharmacy, the 19th edition of this work (now in its 21st), which “for over 100 years has been the definitive textbook and reference on the science and practice of pharmacy”, the recommended daily intake of Lugol’s 5% solution is between 0.1 and 0.3 ml. Lugol’s 5% contains 125 mg of iodine per ml. Therefore, 0.1 ml has 12.5 mg, and 0.3 ml has 37.5 mg of iodine. The authors point out that today, the recommended daily intake in North American and Western Europe varies between 150 and 300 micrograms per day. That’s a factor of 83 and 125 times less, respectively, two orders of magnitude less.

The study

Based on these studies and observations, the authors move on with their own investigation to determine the amount of iodine needed for breast normality, using an amount of 12.5 mg of iodine in the same form as in Lugol’s solution, providing 5 mg of elemental iodine and 7.5 mg of potassium iodide (KI) in a calibrated, silica-coated tablet to ensure precise dosage, and prevent any possible kind of digestive upsets experienced by some taking Lugol’s solution. (The molecular weights of iodine (I) and potassium (K) are 127 and 39. Therefore, their contribution in KI by weight is 76.5% I and 23.5% K. Hence 7.5 mg of KI contains 5.74 mg of I and 1.76 mg of K, and thus a 12.5 mg tablet contains 10.74 mg of I and 1.76 mg of K.)

Ten caucasian women with normal thyroid volume (< 18 ml), and a range of BMIs statistically representative of the general population based on the NHANES III study (1988-94) in which 25% were overweight, and 25% were obese. Five of the subjects had normal BMI (18.5–24.9), two were overweight (25–29.9), and three were obese (> 30). BMI is defined as the weight in kg divided by the square of the height in meters. So that if you weigh 60 kg and measure 165 cm, your BMI is 60/(1.65*1.65) = 22. Underweight is defined as BMI < 18.5.

An interesting observation about thyroid volume measurements, is that the upper limit for a “normal” thyroid is taken to be 18 ml. These ten women’s average was 7.7 ml (with standard deviation 3.6). That’s almost half. Moreover, looking at national averages in a number of countries, the authors report they are found to be as follows (in increasing order): Sweden – 7.7 ml, Holland – 8.7 ml, Hong Kong – 8.9 ml, Ireland – 12.9 ml, and Germany – 16.5 ml. Not surprisingly, the countries with the highest average volumetric measurements are those with the lowest intake of iodine, and are those with the highest incidence of goitre.

After 90 days of supplementation, the most significant improvements that were noted by the participants were decrease in breast sensitivity or pain, decrease in tremors and in restless leg syndrome. There was no significant effect on blood pressure, body temperature, or body composition except for a small amount of fat loss. From the urinalysis, the only significant difference was that the average pH of the ten participants was 6.05 (+/- 0.69) at the start of the trial, and 7.00 (+/- 0.85) at the end of it. This was attributed by the authors to iodine’s antioxidant properties that would naturally reduce the concentration of reactive oxygen species in the cells, and thereby decrease the acid load on the system, leading to an increase in overall pH that would be manifested by an increase in urinary pH as well.

Blood chemistry was monitored using 17 markers. All stayed within their reference range. But although no significant changes were seen, qualitative improvements were seen in 9 of them (e.g., drop in creatine, drop in calcium, drop in albumin, rise in sodium, rise in carbon dioxide).

TSH (thyroid stimulating hormone) stayed within range for most, except for two participants (#1 and #10) who showed remarkable improvements with a drop from 7.8 to 1.4, and from 21.5 to 11.9 mIU/L. These two participants also showed the most significant change in T4 from 9.2 to 7.9 and 8.3 to 5.4 micrograms/dL, while none of the others saw much change in these values. Free T4 and free T3 stayed more or less the same in everyone. Hypothyroidism is defined as having TSH > 6 mIU/L, and it is estimated that of the order of 8 million American women are hypothyroid, but most of them are unaware of it, what is referred to as subclinical hypothyroid.

Breast pain (mastodynia) significantly decreased in 7 out of the 10 participants, and these improvements persisted for at least 3 months after the end of the supplementation. The authors suggest that the potential mechanisms by which iodine can improve breast health and prevent cancer is by neutralising DNA-damaging reactive oxygen species in the cells, by ensuring proper regulation of the cell’s apoptotic function, and by its ability to trigger differentiation (Derry 2001), therefore stopping or reversing the process by which cells lose their specialised functions as they become cancerous. Obviously, these are crucially important properties of iodine that are independent of thyroid hormones.

Discussion and conclusions

The goal of this pilot study was to evaluate the effect of iodine supplementation in American caucasian women, a population with a high incidence of FDB and breast cancer, with a daily iodine intake comparable to that of women living in Japan with a very low incidence of both FDB and breast cancer. A key aspect of the study was to measure thyroid function and investigate evidence of toxicity. They identify and discuss three potential adverse effects of iodine supplementation: iodism, iodine-induced hyperthyroidism (IIH), and iodine-induced goitre (IIG).

Iodism—an unpleasant brassy/metal taste in the mouth, increased salivation, nausea, and headache in the frontal sinuses—was reported in previous studies on several occasions by people taking 150 mg/day or more. The authors mention that it could have been due to traces of bromine or iodate in the supplements. None of the participants reported signs of iodism in this study.

Iodine-induced hyperthyroidism (IIH)—a condition that occurs in iodine-deficient people in the early stages of iodine supplementation—is described in The Thyroid (8th edition, 2000) by Werner & Ingbar in the following terms: “iodine deficiency increases thyrocite (thyroid cells) proliferation and mutation rates. Possible consequences are the development of autonomous hyper-functioning nodules in the thyroid…and hyperthyroidism. Therefore, IIH is an iodine-deficiency disorder.” None of the participants developed IIH in this study.

Iodine-induced Goitre (IIG) and hypothyroidism—a condition that occurs only under very high doses around 2 g/day (2000 mg/day), and seen in some patients when iodine is used as an expectorant in treating asthma, chronic bronchitis, and emphysema—was not seen in any of the patients of this study. It is noted that people with normal thyroid function taking up to 150 mg/day will see decreases in plasma T3 and T4 concentrations with small compensating increases in TSH but all remaining within normal range. However, in people with thyroid disorders, supplementation can induce IIG, and therefore, supervision through regular blood testing of thyroid markers is important.

It has been obvious for a long time that women need more iodine than men. Evidence of this was seen in Marine’s study in Ohio in the 1920’s, where goitre was 6 times more prevalent in teenage girls than in boys of the same age. Marine also showed that supplementation with the equivalent of 9 mg/d of iodine prevent goitre almost completely, although a few still developed it over the 2.5 year period of the experiment. It has also been known for some time that iodine deficiency leads to abnormalities of the mammary glands.

Studies on female rats by Esquin et al. showed that iodine supplementation was essential to prevent FDB and cancer, and using molecular tracing techniques, also showed that the thyroid preferentially concentrates iodide, whereas breast tissue concentrate iodine. Thrall & Bull (1990) confirmed Sequin’s findings, and in addition, showed that skin cells, as the thyroid, concentrate iodide, whereas the stomach cells, as the mammary glands, concentrate iodine. Therefore, these two forms—iodine and iodide—are not interchangeable as it was believed for a long time, and both forms are needed and essential for healthy physiology.

To establish how much is needed for the breast and thyroid separately, having at this point established that the amount needed for mammary gland sufficiency must be around 12.5–13.8 mg/day, involves establishing the amount of iodine needed for proper thyroid function. For this, the authors refer to the work of Saxena et al. (1962) who define thyroid iodine sufficiency as the minimal daily dose required to decrease the uptake of radioactive iodine by the thyroid to at most 5% of the total radioactive dose administered. The rationale and protective strategy is simple: if there is enough normal iodine to fill the thyroid, its cells will not absorb the radioactive iodine (and it will be excreted); but if there isn’t, it will, and that radioactive iodine, lodged in the cells of the thyroid, will, within days, destroy the gland. Saxena and colleagues established that for an adult this minimal effective daily dose is 3–4 mg.

This implies that the thyroid needs at least this much daily in the form of iodide, and that the breasts therefore need at least around 9 mg daily. But note that this is the amount needed to maintain proper function and health. Correcting deficiencies and overcoming disorders of the thyroid like goitre or hypothyroidism, of the breasts like FDB or cancer, or of the skin like psoriasis or eczema, will require more, sometime a lot more, and usually for extended periods of time.

Moreover, for complete protection of the thyroid against radioactive iodine exposure, Sternthal et al. (1980) showed that further suppression can be achieved using higher doses over at least 12 days: 4% absorption at 10 mg, 1.9% at 15 mg, 1.6% at 30 mg, 1.2% at 50 mg, and 0.6% at 100 mg daily, with no risks at all from the supplementation that remains below the 150 mg/day threshold beyond which some adverse effects can sometimes occur.

Abraham, Flechas and Hakala conclude by stating their intention to expand this pilot study and build a database to develop a protocol for iodine supplementation in FDB and other conditions such as subclinical hypothyroidism.

What is clear from reading this paper is that everyone, but especially girls and women, would benefit from taking more iodine and iodide in amounts of at least 12.5 mg/day. For some this could be lifesaving. And because there are no risks, there are no reasons not to. Furthermore, it was also made clear that much larger doses up to 150 mg/day can be taken, still without risks of adverse reactions, and with the potential benefits of much improved health and powerful healing of very serious conditions such as breast cancer.

We will continue this series with an article by the same three authors entitled Orthoiodosupplementation: Iodine sufficiency of the whole human body.

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