Hey Brew, did you get any more Yeet?
We’re running low.
I picked some up from that strange man in the
hazmat suit behind the old video rental store.
Ah, Jerry.
Good guy.
Oh good, you got the iodized salt too!
Why did you want it again?
We have plenty of regular salt.
Alright, check this out.
“Iodized salt makes you smarter”.
So I’m gonna eat the whole box and
then ace my classes at Hillmark.
Don’t think that’s exactly how it works.
Nah I’m pretty sure that’s exactly how it works.
I did my research.
I saw a study that said adding iodine to salt can
increase people’s IQ scores by over 10 points.
Wait, do you mind if I take a look at that study?
Oh no no no no no, not the music, Brew don’t ruin this for me.
This episode concerns nutritional science.
And as always we recommend you consume in moderation, and
speak to your doctor if you have any further questions.
And with that out of the way,
Let’s get into it.
You may have seen articles that
claim that iodine makes us smarter.
One such claim comes via Iodeal Brands, a chemical
supply company that specializes in iodine derivatives.
Yeah, but like, they make this stuff, of
course they’re gonna tell us it’s good for us.
Astute observation.
Is the claim that iodized salt makes us smarter, true?
Or is it just some clever marketing to
get us to buy something we don’t need?
First off, Iodine is an essential micronutrient
our body needs, like vitamins, or iron.
About 70% of Iodine is stored in the thyroid, a
small gland located just under your Adam’s apple.
Iodine is a key precursor to many of the hormones
produced in this gland that aid in metabolism, digestion,
fertility, and heat production, among other things.
Iodine also affects the hippocampus, which deals with
emotions and memory, myelin, which helps electrical
impulses move along nerves, and neurotransmitters,
which transport chemical messages within the brain.
The WHO has estimated that close to 30% of the world's
population has an inadequate supply of iodine in their diets.
Iodine deficiency can lead to goiters, aka enlarged
thyroid glands, which can lead to impaired breathing,
subtle decreases in IQ, and, in severe cases, a
condition called “congenital iodine deficiency syndrome”.
The most severe effects of iodine
deficiency are felt in utero though.
It can lead to low birth weight, and decreased survival rate.
Deficiency in iodine during pregnancy and a child’s
first two years of life, can lead to speech,
learning, reading, and behavioural disorders.
Even mild iodine inadequacy in childhood can
lead to reduced intellectual and motor function.
In the 1830s, French chemist, Jean Baptiste Boussingault,
noticed that there was an increased presence of
goiters in populations living in places where naturally
occuring iodized salt was not frequently consumed,
connecting goiters, to iodine deficiencies for the first
time, and recommended public health interventions to
supplement iodine into salt reserves to combat this.
Industrial iodization of salt didn’t pick up until many years
later due to the economic cost and other health concerns.
Prior to the 1920’s, endemic iodine deficiency
was prevalent in the Great Lakes, Appalachian, and
northwest regions of the United States, cheekily
being dubbed the “goiter belt” where 25-70% of all
children had some level of enlarged thyroid goiter.
Michigan physician, Simon Levin, noticed that of the 583
men he checked for military fitness, 30% had the presence
of a goiter that would disqualify them from service.
In later years, the Michigan State Department of Public
Health determined that the presence of goiter increased
to 60% of the population in some parts of the state.
The United States didn’t begin industrial iodization in salt
to combat the prevalence of goiters until 1924, and it worked!
However there was a side effect of
iodization that no one predicted.
Economists Freyrer, Weil and Politi, used military data taken
during the draft to determine if there was any geographic
correlation to intelligence before and after iodization.
They determined that generally, the higher one scored
on the military’s standardized testing, the more likely
they were to be assigned to the air force, and those
who scored lower would be assigned to the ground forces.
They discovered that the men born in the most iodine
deficient areas before 1924 were more likely to be drafted
into the ground forces, and men from the same area born
after 1924 were more likely to be assigned to the air force.
So wait, once Iodine was introduced,
their test scores went up?
That’s what these economists believe.
There’s been more research on this topic in recent years too.
A meta-analysis of data taken from The Chinese
Medical Reference Database, Medline, and Cochrane
Library compared the IQ’s of children born in
areas of varying iodine sufficiency in China.
Over 12,000 children were included in these studies, and
found that those living in iodine sufficient areas had,
on average, IQs 9.85 points higher than those living
in Iodine deficient areas without supplementation.
So is iodine actually making people smart then?
Was I right, huh?
It’s hard to say.
This study notes that “The intelligence damage of
children exposed to severe Iodine deficiency was
profound, demonstrated by 12.45 IQ points loss and they
recovered 8.7 IQ points with iodine supplementation”.
The effect of iodine on intelligence isn’t so
much that it’s increasing your IQ, but rather
keeping you from losing cognitive function.
Oh it’s like water!
Someone’s talking about me.
Drinking water isn’t like a magic potion that makes
you a superhero, it just makes you not dehydrated.
Yes!
It’s possible that iodine supplementation is making
us smarter, but it’s equally possible that we’re
just seeing what happens when an entire population
finally gets enough of an essential nutrient.
There are a myriad of pop-science articles
that make bold claims from this information.
Some go as far to claim that
Iodine is behind the Flynn Effect.
The Flynn effect?
What’s that?
It’s the name for the observed
increase in IQ scores over time.
The titular James Flynn noticed that between
1932 and 1978, IQ scores increased by 13.8
points on average, a 0.3 point increase per year.
Huh, so people are getting smarter over time?
Not necessarily.
IQ is a bit more specific than just the
numerical value of one’s intelligence.
It’s more like the numerical value of one’s logic
skills, abstract reasoning ability, and working-memory
capacity but they’re not the only form of intelligence.
Someone who scores very low on an IQ test, may very
well do better in life than one who scored higher.
Just because your IQ is higher than someone
else's doesn’t mean you’re smarter than them.
In the immortal words of Dr.
Stephen Hawking “people who boast about their IQ are losers”.
Psychologist Eric Turkheimer found that children from
higher socioeconomic status expressed more deviations
in IQ scoring based on genetic factors, while children
from lower socioeconomic status expressed more
deviations in IQ scoring based on environmental factors.
So when we consider IQ to be the measurement
of one’s intelligence, we might actually just
be testing whether or not that person had the
same opportunities to learn as someone else.
Well that seems, kinda unfair?
It reminds me of my favourite Einstein misquote: If
you judge a fish by its ability to climb a tree, it
will live its whole life believing that it is stupid.
It’s easy to see the relationship between
iodization and IQ and assume that it’s like the
movie “Limitless”, where you just need to take
a pill and suddenly you’re a genius mastermind.
As with most things nutrition, nothing is
going to act like a magic potion that suddenly
makes you better than you were before.
In reality when we see data like IQ increases,
it’s more likely that we’re removing negative
effects, than adding a positive effect.
For example, if we compare humans who drink
water regularly, to those who don’t, we
find a 100% increase in life expectancy.
Does that mean that drinking water will make us live longer?
No.
It just means that if you don’t stay hydrated, you’ll io-die.
Just like what happened to two women
who got stuck in an elevator for 4 days.
Check out our video on that, here!
Ohhh boy, that was a pretty fun episode don’t you think?
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