The history of iodine in medicine Part III: thyroid fixation and medical iodophobia

Original Internist, June, 2006 by Guy E. Abraham

The thyroid gland-iodine connection was known just a few years following the discovery of iodine in seaweed in 1811. Only eight years after this discovery, iodine was used effectively in the treatment of simple goiter. However, the medical uses of iodine during the first century since the discovery of iodine were not restricted to diseases of the thyroid gland only but covered a wide range of clinical conditions. (1)

In the early 1920s, Marine reported a positive effect from iodide supplementation at 9 mg/day in the prevention of simple goiter among adolescent girls. (2,3) That amount of iodine was based on research performed on farm and laboratory animals regarding the effect of iodine on thyroid function and also overall performance. However, in Marine's studies on adolescent girls, the only parameter assessed was the presence of goiter. Following Marine's studies, iodine sufficiency became associated with the absence of goiter, not overall performance such as grades in classes, number of absences due to sickness, etc.

As a public measure to control goiter, iodization of table salt was implemented successfully in the US between 1917 and 1924. That is, iodization of table salt was successful in decreasing markedly the incidence of simple goiter in the supplemented population. Keep in mind that the amount of bioavailable iodine (0.05 mg/day) needed to prevent cretinism, endemic goiter, and hypothyroidism is 60 times less than the amount of iodide (9 mg/day) used by Marine (2,3) in the original studies. Thyroidologists assumed that, with iodization of table salt, iodine deficiency became a thing of the past. That was the beginning of thyroid fixation.

Prior to the iodization program, the public was relying on iodine preparations from apothecaries for their iodine needs. The recommended daily amount of iodine was 0.1-0.3 ml Lugol containing 12.5-37.5 mg elemental iodine. (4) This is exactly the amount of iodine needed for whole body sufficiency, based on a recently reported iodine/iodide loading test by the author. (4) Some propaganda was used following iodization of salt to discourage the public from using the iodine preparations, such as Lugol solution, and to rely instead on iodized salt for their iodine needs. In 1926, physician C.L. Hartsock, from Cleveland, Ohio, (5) wrote: "Iodized salt is now being very much more extensively used by the public than other forms of iodine, such as sodium iodide, iodostarine and compound solution of iodine (Lugol's solution), probably because of the propaganda to insure its use ..."

Iodized salt was unfortunately used as substitute for the previously recommended forms of iodine/iodide. The bioavailable iodide from iodized salt is only 10% of the estimated 0.75 mg iodide in iodized salt consumed per day. (6) That amount, 0.075 mg of bioavailable iodide, represents less than 1% of the amount of iodide used in Marine's study (2,3) (i.e., 9 mg) and also less than 1% of the recommended daily intake of iodine from Lugol solution. Implementation of iodization of salt was associated with an increased incidence of autoimmune thyroiditis. (4)

Instead of iodized salt, Hartsock (5) recommended the use of a tablet of iodine/iodide in known and fixed amounts as the best form of supplementation, just like the most popular form of supplementation used today for vitamins, minerals, and trace elements: "Tablets containing definite amounts of iodine seemed to be the method of choice."

With the availability of thyroid hormones in the 1930s, iodine was completely ignored by thyroidologists in the treatment of iodine deficiency-induced goiter and hypothyroidism. A textbook, Diagnosis and Treatment of Diseases of the Thyroid, edited by Amy Rowland and published in 1932, contained chapters from 24 thyroidologists of that time. (7) Although the most common cause of hypothyroidism and simple goiter worldwide is iodine deficiency, the recommended treatment of hypothyroidism was summarized in two sentences: "The treatment of hypothyroidism of any type consists merely in the substitution of thyroid extract for the deficient secretion. Any form of prepared gland or the active principle, thyroxin, may be used."

Iodine neglect in the 1930s by thyroidologists progressed to medical iodophobia in the late 1940s and early 1950s. Following World War II, there was a systematic attempt to remove iodine from the food supply of America. Iodophobic misinformation permeated all textbooks of medicine and the subspecialties. From books written by physicians for physicians and for the consumers, iodophobia, which has reached pandemic proportions, trickled down to books written by lay persons for consumers. (4,9)

A new syndrome, medical iodophobia, was recently reported. (4) Medicoiodophobes suffer from: 1) split personality which results in iodophobia within the orthoiodosupplementation range previously used safely and successfully in medical practice and iodophylia for megadoses of iodide (up to 12 g/day); 2) double standards which render those physicians intolerant to the minor side effects of the inorganic forms and extremely tolerant toward severe side effects of the radioactive and organic forms; 3) amnesia toward the inorganic, non-radioactive forms when making therapeutic decisions; 4) confusion, attributing the severe side effects of organic iodine containing drugs to inorganic iodine/iodide; and 5) altered state of consciousness, allowing doublethink, doublespeak, and contradictory logic to become acceptable.