By: Dr. Alan Christianson

Remember how Goldilocks wanted her porridge not too hot, but not too cold, and her bed not too hard, but not too soft? Iodine is like this. Too little is not good, and too much is not good.

Despite the fact that iodine is likely the most studied nutrient on the planet, so many ask about iodine because a small (but vocal) group has made claims that run contrary to the knowledge we have built up over the last century.

The following is a specific discussion about these claims that I first wrote over a decade ago. Please enjoy, and if you would like a more technical and well-referenced article on iodine, I have one here:

In Arizona, many retirees spend their summers elsewhere. To me, it marks the change of seasons to welcome my ‘snowbirds’ back in the fall and see them off in the spring. Several years ago, I had a kind gentleman return for the winter with new symptoms: watery diarrhea after every meal and a non-intentional tremor of his hands. The diarrhea started three or four months ago, the tremor, more recently. Normally in excellent health, Tim joked about getting old and his body falling apart. He had his screening tests completed before I heard about this. His tests were normal, except his thyroid levels were too high. He was not on thyroid treatment and had no history of thyroid disease. During his exam, I found several thyroid nodules that were not present last year, and his heart rate was over 100 beats per minute at rest. Further tests showed me that Tim had a multi-nodular goiter. In senior men, this is quite rare, but when it happens, it is usually caused by high-dose iodine exposure, such as in contrast imaging. I asked if he had a CT or MRI done recently. He told me he did not but that he’d been taking an iodine pill for five months. Apparently, he had been tested, found to be low in iodine and was now taking one tablet of Iodoral daily, providing 50,000 mcg of iodine. Within several months, I had roughly the same thing happen to five other patients, all after taking high-dose iodine. One patient also had a toxic, multi-nodular goiter, one had Grave’s disease and one was hypothyroid secondary to Hashimoto’s thyroiditis. Since then, dozens more have come in with new thyroid disease after taking high-dose iodine. To be clear, not all patients who take high-dose iodine will get thyroid disease, just like not all smokers get lung cancer. Iodine in doses above nutritional requirements is the single, best-documented, environmental toxin capable of inducing autoimmune thyroid disease (ATD).1 I had dimly been aware of iodine becoming a new topic at holistic conferences. A little digging quickly revealed “The Iodine Project” as the source of the new ideas on iodine. The Iodine Project was a series of articles by Guy Abraham, MD, originally published in the magazine, The Original Internist (, a non peer-reviewed journal. These concepts have also been found verbatim in books from Dr. David Brownstein (Iodine: Why You Need It, Why You Can’t Live Without It) and articles from Drs. Donald Miller and Jorge Flechas. Over the next several months, I read every word written to date in The Iodine Project and related works, as well as all of their references that were available. I also read everything I could find from every other source on human iodine requirements. Since these views on iodine are getting more pervasive, I felt compelled to share my findings and experiences in a broader forum, thus this article came about. The Iodine Project can be summarized as the following claims:2
  1. High-dose iodine helps conditions, such as fibrocystic breast disease; therefore, these doses are necessary for everyone.
  2. The Japanese consume much more iodine than Americans and have lower rates of thyroid disease and breast cancer.
  3. Iodine status can be determined by 24-hour, urine-iodine levels following a 50,000 mcg oral dose. Those excreting a smaller fraction of the dose may have retained more iodine; therefore, their bodies needed it.
  4. Adult humans need 12,500 – 50,000 mcg of iodine for good health.
  5. Iodine overdose is not a real phenomenon and the “Wolff-Chaikoff effect” is a delusional construct, resulting from “iodophobic bioterrorism.”
  6. The topsoil of the earth was divinely created 6000 years ago with an extremely high level of iodine, which was depleted by the flood of Noah. Human health has been poorer ever since.
  7. The current, academic views on iodine are distorted by international, foreign powers in order to make zombies out of Christian America.
I imagine most who have entertained these ideas had no idea how radical some of the essential, underlying concepts are. Dr. Abraham states that the whole body of his work depends on the points 6 and 7 to be valid. These last points are so extreme, they deserve a few direct quotes (parentheses mine): “The theory of evolution does not offer an intellectually satisfying answer to this paradox (humans needing iodine levels greatly in excess of what is found in sea water, as The Iodine Project proposes)…Therefore, the original planet earth contained a topsoil rich in iodine, and all elements required for perfect health of Adam, Eve and their descendants…A sequence of events followed, culminating in the worldwide flood 4500 years ago. Following this episode, the receding waters washed away the topsoil with all its elements into oceans and seas. The new topsoil became deficient in iodine and most likely other essential elements, whose essentialities are still unknown.”3 “Iodine neglect in the 1930’s by thyroidologists progressed to medical iodophobia in the late 1940’s and early 1950’s. Following World War II, there was a systematic attempt to remove iodine from the food supply of Christian America. Iodophobic misinformation, well synchronized with the introduction of alternatives to iodine supplementation in medical practice, strongly suggest a well planned conspiracy by agents of foreign powers planted at strategic positions in academia and the regulatory agencies.”4 The Iodine Project’s claims that iodophobia is part of a large conspiracy beginning in the 1930’s. He discusses how, in the 1960’s, Americans nearly became released from the “zombifying” clutches of iodophobia: “In the early 1960’s, potassium iodate was added to bread as a dough conditioner. This was an oversight by the agents of foreign powers planted at strategic positions in academia and the regulatory agencies…This amount of the dezombifier iodine in a major staple food of Christian America could not be tolerated for long.”5 My responses to the claims are as follows: Point #1 – The Iodine Project states that Dr. Abraham’s focus on iodine began after learning about the role of high-dose iodine in treating fibrocystic breast disease in women. The data that high-dose iodine can help fibrocystic breast disease is clear. However, a useful property of a substance at a high dose does not mean that dose is nutritionally necessary or even safe. Nutrients are cofactors for physiological functions in the body. Some also happen to have useful effects when used in doses well in excess of physiologic requirements. Take niacin as a case in point. As adults, we require only 14-18 mg of niacin to prevent us from pellagra, a fatal, deficiency disease. With a diet high in the amino acid, tryptophan, we can do fine on even lower amounts of niacin. It happens to be that doses of niacin 100-200 times this can act as a gentle HMG CoA reductase inhibitor, yet these doses can cause maculopathy in up to 7% of adult males who take it.6 The majority of adults can tolerate intermittent, high doses of iodine with no adverse effects. Long term elevations, such as The Iodine Project proposes, are different. Those who are low in iodine, or who have positive thyroid antibodies, can have adverse effects by raising their long term intakes as little as 100 mcg.7 Those who are not deficient can manifest toxicity with as little as 600 mcg daily. The WHO has stated that 1000 mcg is a safe, upper limit for most without thyroid antibodies. Thyroid antibodies are commonly present with normal thyroid function and can be found in up to 26% of the population. I did not find recommendations to pre-screen for antibodies prior to treatment in The Iodine Project.8 Point #2 – The Japanese, especially those in coastal areas, do consume more iodine than Americans but have higher rates of thyroid disease. Furthermore, their thyroid disease is highest in their areas of greatest iodine intake.9 Other populations, whose iodine intakes vary from 100 – 200 mcg daily, also have higher rates of thyroid disease.10 Japanese women used to have lower rates of breast cancer than American women. This difference declines as they adopt a western diet. Researchers have shown strong, dose-related increases in breast cancer among women from different nations related to dietary fat and inverse, dose-related risks to soy food and green tea.11,12,13 Point #3 – I have been unable to find any sources outside of The Iodine Project pertaining to the validity of 24-hour loading tests, even after asking directly. Based on what we know about iodine, this test is not likely meaningful for the following reasons:
  • We excrete iodine in our urine, but variable amounts leave though our bowels and sweat.
  • Sudden, large doses can result in fecal loss 400-fold above normal.
  • It has been stated that unless fecal and urine levels of iodine are measured, urine is not an accurate biomarker when iodine intake is changed abruptly, such as after a loading dose.14
The CDC has also documented that a population’s 24-hour, urinary, iodine-output levels are only meaningful when iodine intake has been steady for six months or greater. One does not reach a steady state in 24 hours.15 Point #4 – Due to predictable, thyroid toxicity, no nutritional organization has endorsed intakes of iodine above 600 mcg daily. Iodized salt is ideally 1/10000 potassium iodine, but many third-world attempts ended up wrong. Since the WHO has carefully tracked these cases, we have extensive data regarding changes of iodine intake. Long-term intakes above 600 mcg routinely cause higher rates of thyroid disease, including hypothyroidism and hyperthyroidism.16 Here is a table with the recommended dietary intakes of iodine and upper limits by group.17
Group Recommended Intake (mcg/kg/day) Upper Limit of Safety (mcg/kg/day) Iodine Project Proposed Intake (mcg/kg/day for a 60 kg adult female)
age 13-adult 2 30 208 – 833
Additional data on the long-term effects of high-dose iodine come from amiodarone usage. Each 200 mg tablet is roughly 75 mg of organic iodine, 8 – 12% of which is released as free iodide, yielding an average net dose of 6 – 12.75 mg of iodine. Dronedarone is a nearly identical molecule to amiodarone, minus the iodine. It shares the same effects and side effects of amiodarone with the exception of thyroid toxicity. Therefore, it has been concluded that the thyrotoxic effects of amiodarone are attributable solely to the high iodine content.18 In a study of 182 patients taking amiodarone, 41% developed hypothyroidism over a six-year period. Median time frame of onset for hypothyroidism was 21 months. 59% of patients developed thyrotoxicosis after an average of 29 months. Note that some cases of thyrotoxicosis culminated in hypothyroidism, so the groups did overlap.19 Point #5 – The Wolff-Chaikoff effect, AKA the “iodine escape mechanism,” has been verified in vitro and in vivo and is present in all humans without exceptions or variations. Were such a fuse not in place, normal variation of iodine intake could induce cardiotoxic hyperthyroidism. This effect is used when managing patients in a state of hyperthyroid storm. One can suppress thyroid hormone synthesis with pharmacologic doses of iodine more quickly than with thionamide drugs, due to the Wolff-Chaikoff effect. This also enables a single, high dose of potassium iodine (SSKI) to prevent thyroid cancer after radiation exposure. After taking enough SSKI, the thyroid iodine uptake is temporarily blocked due to the Wolff-Chaikoff effect. This prevents the thyroid from absorbing environmental, radioactive iodine for roughly three weeks. Point #6 – Religious belief, or lack thereof, is a personal matter. I personally do not find the evidence convincing that the flood of Noah changed the earth’s iodine content. Point #7 – As Carl Sagan said, “Extraordinary claims require extraordinary evidence.” Fibrocystic breast disease can usually be treated with therapeutic doses of Vitamin E, EPO, a diet high in fiber and avoidance of methyl xanthenes (Tori Hudson, ND: personal communication, April 26, 2010). If considering iodine for resistant cases, pre-screen for antibodies and monitor thyroid function. Breast cancer risk can be lowered by management of estrogen metabolism, exercise, cruciferous veggies and trading alcohol for tea. Neither requires a treatment with a significant risk for generating thyroid disease. Finally, thyroid function does not improve when iodine consumption exceeds established ranges. Given that risks of high-dose iodine are irrefutable, long-term intake should be kept at levels of roughly 100 – 300 micrograms for those with or at risk for thyroid disease.   For further reading: The Iodine Project in its entirety: A debate between Dr. Abraham and Dr. Alan Gaby can be found on the Townsend Letter for Doctors and Patients archives: The Agency for Toxic Substances and Disease Registry (ATSDR) has an exhaustive (over 200 pages) summary of human studies on toxicity of iodine: The agency also has 172 excellent references on iodine metabolism: The CDC report on iodine requirements in humans: Iodine status worldwide from the World Health Organization: International Council for the Control of Iodine Deficiency Disorders, working to eliminate global, iodine deficiency:   References: 1. Bahn, R, Chair. Immunogenetics, Epigenetics and Environmental Triggers of Autoimmune Thyroid Disorders. Paper presented at: Spring Meeting of the American Thyroid Association Thyroid Disorders in the Era of Personalized Medicine; May 13-16, 2010; Minneapolis, Minnesota. 2. Iodine Publications. Optimox Corporation. opt_Research_I.shtml. Accessed 5/26/2010. 3. Abraham G, Brownstein D. Validation of the orthoiodosupplementation program: A Rebuttal of Dr. Gaby’s Editorial on iodine. Accessed May 26, 2010. 4. Abraham, G.E., The History of Iodine in Medicine Part III: Thyroid Fixation and Medical Iodophobia. The Original Internist, 13: 71-78, June 2006. 5. Abraham, G.E., The History of Iodine in Medicine Part III: Thyroid Fixation and Medical Iodophobia. The Original Internist, 13: 71-78, June 2006. 6. Fraunfelder F, Fraunfelder F T, Illingworth D. Adverse ocular effects associated with niacin therapy. Br J Ophthalmol. 1995 January; 79(1): 54–56. 7. W Reinhardt, M Luster1, K H Rudorff. Effect of small doses of iodine on thyroid function in patients with Hashimoto’s thyroiditis residing in an area of mild iodine deficiency. Euro J Endocrinology 1998. 139 23-28. 8. Mehran S, Meilahn E, Orchard T, Foley et al. Prevalence of thyroid antibodies among healthy middle-aged women: Findings from the thyroid study in healthy women. Ann Epidemiology 1995; 5(3):229-233. 9. N Konno, H Makita, K Yuri, N Iizuka et al. Association between dietary iodine intake and prevalence of subclinical hypothyroidism in the coastal regions of Japan. J. Clin. Endocrinol. Metab, 78, 393-397. 10. Pedersen I, Knudsen N, Jorgenson H, et al. Large Differences in Incidences of Overt Hyper- and Hypothyroidism Associated with a Small Difference in Iodine Intake: A Prospective Comparative Register-Based Population Survey. J. Clin. Endocrinol. Metab., October 1, 2002; 87(10): 4462-4469. 11. Gregorio DI, Emrich LJ, Graham S, et al. Dietary fat consumption and survival among women with breast cancer. J Natl Cancer Inst. 2003 Jun 18;95(12):906-13. 12. LeMarchand L, Kolonel LN, Nomura A. Ethnic differences in survival after diagnosis of breast cancer—Hawaii. JAMA 1985;254:2728. 13. Yamamoto S, Sobue T, Kobayashi M, et al. Soy, isoflavones, and breast cancer risk in Japan. J National Cancer Inst, Vol. 95, No. 12, June 18, 2003. 14. Vought R, London W, Brown F, et al. Iodine Intake and Excretion in Healthy Nonhospitalized Subjects Am. J. Clinical Nutrition, Sep 1964; 15: 124-132. 15. Toxicological Profile for Iodine. Agency for Toxic Substances and Disease Registry Accessed 5/26/2010. 16. Roti E, Vagenakis G. Effect of excess iodide: clinical aspects. In: Braverman
LE, Utiger RD, eds. The thyroid. A fundamental and clinical text, 8th ed. Philadelphia, PA, Lippincott, 2000:316-329. 17. Fisher DA, Delange F. Thyroid hormone and iodine requirements in man
during brain development. In: Stanbury JB et al., eds. Iodine in pregnancy. New Delhi, Oxford University Press, 1998:1-33. 18. Han TS, Williams GR, Vanderpump MP. Benzofuran derivatives and the thyroid. Department of Endocrinology, Royal Free and University College Medical School, Royal Free Hospital, Hampstead, London NW3 2QG, UK. 19. Martino E, Bartalena L, Bogazzi F, Braverman LE. The effects of amiodarone on the thyroid. Endocr Rev. 2001 Apr;22(2):240-54.