Ask A Scientist© Biology Archive

name         Theresa
status       other
age          30s

Question -   Why do they put iodine in salt?
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Iodine was introduced into salt at earlier this century when it was
discovered that certain areas of the US had a mark deficiency in iodine in
the diet of people, and people developed a neck swelling (goiter).  The
Great Lakes region is one of these areas where the soil is lacking
iodine.  Goiter can be caused when the thyroid gland swells because of a
lack of iodine in the diet.  Most medical advise now states that iodine in
salt is no longer necessary due to our food sources arising from all over
the world.
Steve Sample
York High School
Elmhurst, Illinois
60126
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Hi Theresa...see, there are a variety of elements and
compounds that are necessary for the proper maintenance
of our life. One of these is iodine, since a small
quantity of iodine is needed for the adequate
functioning of the thyroid gland. A deficiency of iodine
produces dire effects, as goiter, where the thyroid gland swollens due to
the lack of iodine traces in the diet.
The iodine affects directly the tyrhoid gland secretions,
which themselves, to a great extent, control heart action,
nerve response to stimuli, rate of body growth and
metabolism.
Iodine is available in seafood, and goiter (or goître)
used to be found particularly  in montaineous regions
and areas far from salt water.
Prevention  of iodine deficiency is most simply
done by eating seafood regularly or by the use of
iodized salt.
To overcome iodine deficits, government health officials
in many countries have made dietary iodine additives
(in table salt) mandatory.
A lack of iodine during infancy may cause a condition
known as cretinism, in which mental and physical de-
velopment is severely impaired. this condition can be
prevented by a food diet with adequate iodine, during
pregnancy.
So when you salt your food, not only you  make it
tasty, but you are giving to your body the essencial
sodium chloride that supplies the chloride ion,
necessary for the production of hydrochloric acid by our stomachs, and the
sodium ion necessary to maintain the proper balance between sodium and
potassium ions that has
great physiological significance.
And...also the two cents of iodine, of course...
Thanks for asking NEWTON!
Mabel
(Dr. Mabel Rodrigues)

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Hello Theresa
In some areas of the world the soils are deficient in iodine and
consequently crops and people's diets are deficient in iodine.  Low iodine
affects the thyroid gland which requires iodine in order to produce thyroid
hormones which play a role in growth and metabolism.  The thyroid becomes
enlarged to compensate resulting in a condition called goiter.

In order to reverse this problem iodine is added to salt.  This is the case
in the USA and was the case in Australia (where I live) until recently.  We
have stopped using iodised salt (although it is still available) because
our diet is much more varied than it used to be.  Consequently we can now
do without the extra salt.

Thanks for the question

Cameron Millsom
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odine is an essential human nutrient, vital to the proper function of the
thyroid gland (it is a necessary ingredient of thyroid hormone).  If a body
is denied iodine, the thyroid swells up, causing a goiter.  Putting iodine
in salt prevents this from happening - it's just like enriching flour by
putting in vitamins.

Rich Barrans
Argonne National Laboratory
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Iodine is necessary for proper thyroid function.  If you don't get enough
iodine, your thyroid works overtime and you get a big thing on your neck
called a goiter, which is a swollen thryoid.  (Your adam's apple is actually
your thyroid-its in your neck-you can feel it going up and down when you
swallow)I was always told that sea salt contains iodine.  Anyway-the soil in
the regions near the sea contain iodine naturally because of the ocean water.
  But when you come inland, the salt in the ground doesn't contain iodine.  So
they add iodine to salt to prevent goiter.

Van Hoeck
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