Obesity and Thyroid Hormone
Americans are living longer and healthier than ever before. For
example, during the decade from 1980 to 1990, life expectancy in
the United States increased nearly two years from 73.7 years to
75.4. Fortunately, during most of our lives we live in a healthy
state. However, these improvements in longevity and health are largely
due to medical advances, rather than lifestyles changes.
Our society, which places such emphasis on thinness and physical
appearance, has been getting heavier. Recent studies have shown
that during the same past decade, the prevalence of obesity has
risen from 26% to 34%.
Quick fix for thinness
There is so much discussion in magazines, newspapers, and television
talk shows on obesity and its treatment that Americans are becoming
hung up over what they should do. Everyone wants to look good in
bathing suits, to wear sexy clothes, and to fit into a suit worn
ten years ago, as if thinness will suddenly change one's life!
Thyroid for weight loss?
Many Americans have become desperate and have turned to various
commercial weight loss programs, many of which have been forced
to close or to change their advertisements because of unsubstantiated
claims of success. Some people will rush to try any treatment that
sounds simple and easy, though it makes no sense, has little or
no chance of working, and is potentially dangerous. We are all part
of the society that stresses the taking of a pill or seeking a quick
fix to instantly cure a problem that has take so many years to develop.
So it is not surprising that some desperate people, and their equally
desperate physicians, will try thyroid hormone in an effort to lose
weight. After all, we all know that "thyroid hormone controls
metabolism" and that "metabolism controls weight,"
so why shouldn't thyroid hormone be an ideal diet pill? Moreover,
many people still respond to questions about their family history
of thyroid disease by stating that their aunt or sister "must
have had a thyroid problem because she was so fat." In addition,
anyone who has had Graves' disease and who lost weight during the
hyperthyroid phase is usually quite happy with that symptom, but
very upset with the regaining of the weight that occurs once the
elevated thyroid hormone levels are brought down to normal.
The day of diet doctors
Years ago, diet doctors were common. Parents would take themselves
or their chubby children to these doctors, many of whom had no formal
training in the treatment of obesity, or in endocrinology. Often
these doctors were physicians who tried whatever fad was popular,
from pills to shots to cookies to liquid protein to starvation,
without a true understanding of obesity and eating behavior.
Once-popular forms of diet pills were called rainbow pills, which
contained "a little digoxin, a little amphetamine, a little
diuretic, and a little thyroid"- all in different color capsules
and only obtainable from the diet doctor's office. It has taken
a long time and even some medical malpractice cases for these doctors
to close down their offices. Yet even today, some patients will
still ask for these types of pills, even for a short time, just
to get a jump start.
Thyroid hormone NOT the answer to weight loss
Thyroid hormone and its role in metabolism are poorly understood,
even by basic scientists and thyroid specialists. Certainly, thyroid
hormone controls the synthesis of certain proteins in the body's
cells. During times of acute or chronic illness there are changes
in thyroid hormone concentrations, perhaps to save the body from
using up is own energy stores. Certainly, some patients with documented
hypothyroidism will have gained five to ten pounds that will shed
after becoming euthyroid. Short of that, there are NO studies showing
any positive effects for long-term weight control for individuals
who have normal thyroid function and who take excess amounts of
thyroid hormone.
It is not for lack of trying! Both thyroxine (T4) and the more
potent triiodothyronine (T3 ) have been tried, both at normal replacement
dosages and at much higher dosages. Some people will lose a few
pounds, but the weight loss comes from breaking down muscle mass,
NOT the fat they desperately want to lose.
Although some very obese people can tolerate very large amounts
of thyroid hormone without adverse effects, most people will soon
become clinically and biochemically hyperthyroid. Older persons
are highly susceptible to the side effects of excess thyroid hormones,
especially T3. Symptoms might include extreme nervousness, restlessness,
insomnia, palpitations, tremors, headaches, and problems concentrating.
This state of excess thyroid hormone may also cause the loss of
calcium from the bones, especially in postmenopausal women.
Treating obesity effectively
Clearly, thyroid hormone has NO role to play in the treatment
of obesity. It should be used only for the treatment of documented
hypothyroidism, suppression of enlarged thyroid glands or nodules,
and in thyroid cancer.
The treatment of obesity requires much more than a magic bullet
approach, including a better understanding of: possible metabolic
defects, psychological stress, resistance to exercise, and triggers
to normal hunger and binge eating.
For now, at least, sustained weight loss can only be attained with
comprehensive life style changes. It is also important to have realistic
expectations of what can be achieved. Attempting to use thyroid
hormone for weight loss is not a quick fix - if anything, it is
potentially dangerous.
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