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Iodine (I2) is a nonmetallic element belonging to the halogen family.
Iodine is converted to iodide in the gut, efficiently absorbed in the
digestive tract and carried into circulation by serum proteins. Most iodide
is actively trapped by the thyroid gland where, as I2, it forms an essential
component of the thyroid hormones, thyroxin (T4) and triiodothyronine.
Thyroid hormones regulate cell activity and growth in virtually all tissues
and are, therefore, essential for both normal embryonic and postnatal
development.
Deficiencies: Iodine deficiency impairs growth and neurological
development, which can damage the brain. Depending on its severity and
stage of development at which it occurs, iodine deficiency can lead to
a wide spectrum of health problems, ranging from mild intellectual impairment
to severe mental retardation, growth stunting, apathy, and impaired movement,
speech or hearing. Cretinism, in which many of these abnormalities occur,
represents the extreme of early iodine deficiency. It is rare. Much more
widespread is an intellectual blunting that may afflict as many as 50
million of the estimated 1.6 billion "at-risk" people living
in iodine deficient regions, making iodine deficiency the most common
preventable cause of mental retardation in the world. Because of decreased
production of thyroid hormones, iodine deficiency causes compensatory
hypertrophy of the thyroid gland as it attempts to make more thyroid hormone,
resulting in a goiter - a disfiguring condition that is common in high
risk areas. Collectively, health problems arising from a lack of iodine
are known as iodine deficiency disorders (IDD).
Prevention and treatment: Universal salt iodization provides the
most effective and affordable means to prevent IDD throughout the world;
over 90 countries presently iodize their salt. Typically, the iodine concentration
is from 30 to 100 µg per g of salt, levels that take into consideration
anticipated losses during transport and storage. At salt intakes of 5-20
g per day, this fortification range is sufficient to meet requirements
in most countries. Iodization costs between 2-7 US cents per kg of salt.
Other iodizable vehicles include water, grain and dairy products. Iodized
oil supplements may be periodically administered in remote areas where
salt iodization is not feasible. Damage to the fetus resulting from maternal
iodine deficiency is irreversible. Most goiters can be cured or reduced
in size with iodine therapy.
Diet recommendations: The Recommended Dietary Allowance for iodine
in the United States is as follows: infants, 40-50 µg; 1-3 yrs,
70 µg; 4-6 yrs, 90 µg; 7-10 yrs, 120 µg; over 11 yrs,
150 µg; pregnancy, 175 µg; and lactation, 200 µg. Globally,
the per capita iodine requirement is 150-200 µg per day.
Food sources: Iodine content of food and water depends primarily
on the supply of iodine in the soil. Glaciated, mountainous or heavy rainfall
areas are likely to be low in iodine placing human and animal populations
at risk. Thus, individuals can not usually improve iodine intake by diversifying
their diet. Some plants, including cabbage, Brussels sprouts, legumes,
and cassava contain goitrogenous substances that interfere with iodine
absorption. This is of public health concern only where these foods are
regularly consumed in large amounts and dietary iodine is low.
Toxicity: A wide range of iodine intake is tolerated by individuals.
For this reason, long term consumption of iodine through iodized salt
is considered safe. Chronic, excessive iodine intakes may occasionally
lead to goiter and hypothyroidism. A small increase in thyrotoxicosis
(<0.1%) may occur from increasing the iodine intake of a population
which has had a low intake for many generations.
Recent research: Epidemiologic advances continue: Indicators of
population status are increasingly correlated with health outcome measures.
In China, Indonesia, Ecuador, Switzerland and Zaire, goitrous communities,
or populations with low urinary iodine excretion, have poorer cognition
than non-goitrous ones, a condition that has been responsive (in terms
of I.Q.) in some studies to iodized salt. New vehicles are being tested,
such as irrigation water in China and sugar in Sudan. In Indonesia, supplementing
infants with iodized oil reduced mortality < 4 mo of age.
Caution! Before starting
to take this medicine, it is vital that you should consult your doctor!
Do not use it on your own initiative, without medical advice.
Also, you should read carefully important health information about this
drug given here:
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