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How
Adding Iodine to Salt
Made America Smarter
By
Alex Greig
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* The
U.S. introduced iodized salt in 1924
* A
new study compares IQ results of people in iodine deficient
areas before and after iodized salt
* Americans
born in iodine deficient areas showed an IQ increase of
15 points after 1924
* Iodine
deficiency causes goiter and mental and physical retardation
in infants
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A
new study indicates that Americans gained up to 15 IQ points after
the addition of iodine to salt became mandatory
In an effort
to prevent goiter related to iodine deficiency, authorities ruled
that iodine be added to U.S. salt products in 1924.
The iodine,
in addition to eliminating goiter, appears to have had an unexpected
result: smarter Americans.
In a report published
in the National Bureau of Economic Research, James Freyer, David
Weil and Dimitra Politi examined data from about two million enlistees
for World War II born between 1921 and 1927, comparing the intelligence
levels of those born just before 1924 and those born just after.
To do this,
they looked to standardized IQ tests that each recruit took as
a part of the enlistment process.
While the
researchers didn't have access to the test scores themselves,
they had another way of gauging intelligence levels: smarter recruits
were sent to the Air Forces, while the less intelligent ones were
assigned to the Ground Forces.
Next, the
economists worked out likely iodine levels in different cities
and towns around America using statistics gathered after World
War I on the occurrence of goiter.
Matching the
recruits with their hometowns showed researchers that the men
from low-iodine areas made a huge leap in IQ after the introduction
of iodine.
The men born
in low-iodine areas after 1924 were much more likely to get into
the Air Force and had an average IQ that was 15 points above that
of their slightly older comrades.
This averages
out to a 3.5 point rise in IQ levels across the nation.
The World
Health Organization backed up these results saying:
'For iodine-deficient
communities, between 10 and 15 IQ points may be lost when compared
to similar but non-iodine-deficient populations.'
Iodine comes
from food sources, and is especially abundant in seafood and foods
grown in coastal areas with high levels of iodine in the soil.
Mountainous
and inland areas are often very low in the nutrient, meaning food
grown there doesn't have enough iodine.
Today, iodine
deficiency is the leading cause of preventable mental retardation
in the world. The condition, known as cretinism, was also common
in the U.S. until the introduction of iodized salt.
Originally,
U.S. authorities wanted to reduce the incidence of goiter, but
research since that time has shown that iodine plays an important
role in brain development, especially during gestation.
The World
Health Organization estimates that two billion people worldwide
are at risk of iodine deficiency.
And it's not
just a Third World problem – the WHO reports that only 27
percent of households in Europe have access to iodized salt.
The researchers
say that iodine may also be a cause of the so-called Flynn
Effect, the steady rise in IQ that's been ongoing since the
1930s.
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It should
be noted that the amount of iodine people get from iodized table
salt, while it can prevent the worst case scenario of iodine deficiency
– goiter – it is not enough for whole body tissue
sufficiency, which is needed for optimal operation of
the thyroid and the organs that comprise the immune system. And
since we're not going to get any from natural foods, the foods
that health-minded people eat, and these people are also likely
to not use table salt, if you don't supplement your diet with
iodine, you're setting yourself up for a world of hurt. But this
should be done properly and optimally with guidance from an iodine
literate practitioner.
More
important iodine info here.
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