Iodine, Glaciers and Goiter


The thyroid gland in front of the wind pipe in the neck normally weighs a little over half an ounce and contains about 95% of the iodine in the body.  Iodine is an essential ingredient of thyroid hormone necessary for normal metabolism and development, especially of the brain.  Iodine enters the body mostly in food. The thyroid gland can concentrate it to several hundred times the level circulating the blood, especially when the intake is low. This ability to concentrate available iodine is necessary for the synthesis of thyroid hormone.  In the absence of an adequate intake of iodine the thyroid gland enlarges in an attempt to compensate for the deficiency.  Some individuals inherit a slightly reduced ability to accomplish this concentration. This is no handicap to these people except when iodine is deficient in their diet.  In that case their thyroid glands enlarge dramatically attempting to compensate. They are said to have endemic goiter and regions of the world with increased numbers of people with goiters are called goiter belts. The first goiter belts noticed were in the Alps and Pyrenees of Europe and the Great Lakes region of North America. In all those regions the soil is deficient in iodine because melting glaciers dissolve iodine and carry it to the sea.


This explains why sea water has ample dissolved iodine and salt water fish are good dietary sources. The first successful public health intervention to reduce the incidence of goiter and thyroid deficiency was one pill per week of a milligram or so of iodine administered to the general population. Some of us remember receiving these pills at school. Soon it proved more convenient to mandate the addition of a tiny amount of iodine to table salt before marketing.  Meanwhile, in the developed world we get food shipped in from all over the map, and iodine deficiency scarcely occurs even in people who do not eat salt.


Goiter and its complications are not the most serious consequences of iodine deficiency.  Babies borne to iodine deficient mothers and infants with inadequate iodine intake suffer from incomplete brain development. This is not totally reversed by restoration of the deficiency after the disease becomes apparent.  Worldwide this is a major cause of mental retardation, and it is easily preventable by iodine supplements especially to women and young children in regions of endemic goiter. Kiwanis Clubs have taken this on as a very cost effective project. The budget needed for the entire world is only a few tens of millions of dollars. The history of iodine deficiency and its prevention is another example of public health measures deserving a priority over curative medicine because they are so cost effective.


A few interesting factoids about iodine and goiter: When the thyroid gland enlarges in response to iodine deficiency it is because the pituitary gland "cracks the whip" by secreting TSH (thyroid stimulating hormone).  Giving thyroid hormone in pill form stops the stimulation and the goiter shrinks.  If the amount of thyroid given artificially does not exceed what the normal gland should produce, no excess occurs because the pituitary totally shuts down stimulation, and the only hormone present is from the pills.


Giving large amounts of iodine has seemingly paradoxical effects depending on the physiological state and can either reduce or increase hormone release. Large amounts of iodine are very convenient for purifying drinking water by killing more different kinds of germs than chlorine. The U.S. Peace Corps no longer recommends iodine for long-term use for this purpose.   (Volunteers who were adversely affected quickly returned to normal on ceasing to use iodine).  Large doses of iodine are also used for blocking radioactive iodine after a nuclear accident, Three Mile Island for example.  When the gland is recently saturated with iodine, it scarcely takes up any additional iodine that comes its way.  This prevents radiation damage from radioactivity that would otherwise have been highly concentrated in the thyroid.


No substance, which has ever caused cancer in animals, is permitted in foods. Aminotriazole was a weed killer found in cranberries when Richard Nixon was running for office. It was known to cause cancer in animals when fed in very large amounts.  Mr. Nixon ate cranberries whenever convenient while campaigning in Wisconsin. His advisors probably told him that aminotriazole caused cancer because it inhibited thyroid hormone release causing excess TSH stimulation and occasionally caused cancer in animals. Carcinogens had long been considered harmful in any dose assuming no threshold below which the substance was acceptable. But if aminotriazole was present in a sufficiently low dose to cause no thyroid stimulation to occur, no harm could result since it is not a carcinogen on contact. Similar tiny amounts of aminotriazole are normally present in cabbage and cause no goiter or cancer. So don’t hesitate to eat cabbage.  Chalk one up for “Tricky Dick”.


John A. Frantz, M.D.

March 9, 2002







Psychosis is a symptom, not a diagnosis.  Compare with fever, which is a prominent symptom of many illnesses.   Schizophrenia is a very common cause of psychosis.  Alzheimer’s disease is an example of another disease that also occasionally causes psychosis.  Patients with either of these diagnoses might hear voices that the rest of us cannot hear.  When we give an anti-psychotic medication, which suppresses the symptom, we have not cured psychosis.  Aspirin might suppress fever in the presence of pneumonia, but it never would enter our minds that we had cured the pneumonia.


An example from my professional past:  When Thorazine, the first anti-psychotic drug, arrived on the market, I gave it to Alice, a long-term schizophrenic patient at the nursing home.   She seemed to stop hearing voices.  After a few months of this success, she and I were having a friendly conversation.  I asked Alice, “Does Thorazine really stop you from hearing voices, or does it just help you not to talk about them?”  She thought for a moment and replied,  “Maybe it just helps me not to talk about them.”  Thorazine had not helped to organize her life, so this was the beginning of the insight that psychosis is merely a symptom not a diagnosis.


John A. Frantz, M.D.