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.
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.
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