For about a hundred years, table salt has been fortified with the essential nutrient
iodine. Over that time, some pretty horrific health problems that used to be commonplace
have all but vanished from the developed countries where most of you apparently live, according
to my analytics.
However, there's reason to believe that people aren't eating as much of this stuff as they
used to — I know I'm not — and that has some public health folks worried. A guy like
me probably doesn't have to be too concerned because I get iodine from lots of other foods,
notably dairy and seafood.
But if you're pregnant or you could become pregnant, the experts definitely say you should
be making a conscious effort to make sure you're getting your iodine — also, if you
are a vegan.
In the context of nutrition science, iodine is considered an essential mineral. It's in
there with things like iron, zinc, manganese — things we all need to ingest in small
amounts in order to live.
In the context of like every other science, iodine is a chemical element found throughout
the universe and across the surface of the earth, most notably the ocean. That's why
people in coastal areas historically have not had much trouble with iodine deficiency.
There's iodine in marine fish, and also in edible seaweeds.
Iodine from the ocean also makes its way into the soils on land, and from there it gets
into fresh drinking water, and all kinds of food crops grown in iodine-rich soil.
But of course, not everybody lives in coastal areas, and even then it's not that simple.
The distribution of iodine across the earth's landmasses is kinda weird. There are some
coastal areas that don't have that much iodine, and there's some inland areas that actually
have a lot of iodine.
Geologists suspect this might be the result of glaciation in the last ice age — glaciers
moving stuff around the continents.
But an example of a very big region with very low iodine is that way.
"The northern portion of the United States was known as the goiter belt, with sort of
an area of focus right around the Great Lakes region in the Midwest."
This is Dr. Elizabeth Pearce, an endocrinologist and professor at Boston University's med school,
and yeah, it's time to talk about goiters.
"So, a goiter just means thyroid enlargement, and it can be something that's very subtle,
where it can really only be detected by doctors using ultrasound. But it often, in profoundly
iodine-deficient regions, can be huge — it's sort of like this, on the front of the neck.
It's very uncomfortable, as you might imagine — just a lot of extra tissue taking up space
that can make it challenging to swallow, make people have a chronic cough, because it's
pushing on the wind pipe.
Just a century ago, so many people from Pennsylvania to Washington State had swollen thyroid glands,
and this might never have been documented had it not been for the young Serbian nationalist
who assassinated Austro-Hungarian Archduke Franz Ferdinand in 1914, sparking the First
World War.
"A huge proportion of potential military recruits from Michigan were considered ineligible for
service, either because they had intellectual impairment, probably from their mothers having
been iodine-deficient when they were pregnant, or because they simply had goiters so large
they couldn't fit their necks into a military uniform."
Yikes, right? Our bodies need iodine to make thyroid hormone, and we use thyroid hormone
to regulate our body's usage of energy from food. A lot of the ailments associated with
chronic iodine deficiency have been known historically as cretinism. This is where the
insult "cretin" comes from: goiters, low energy, sometimes weight gain, and in the children
of iodine-deficient mothers, intellectual disabilities. That's the big one.
The idea of fortifying salt with iodine was first implemented in Switzerland in 1922.
Switzerland is that way. Salt was the logical place to put it. Everybody eats salt every
day. At the chemical level, iodine bonds easily to salt — there's iodine naturally in sea
salt like this, though not nearly as much as you need.
And contrary to popular belief, you probably cannot taste the iodine in salt. There have
been studies with tasting panels. It does not affect food quality.
The U.S. salt industry also started iodizing salt voulentarily in the 1920s. A couple of
decades later, WWII happened. All the young men in the upper-Midwest had to report to
their local draft boards again and get physicals. It was the perfect case study to see if iodine
supplementation was working, and boy was it. The goiter belt was simply gone, and it was
the same story in countries all over the world, quite notably some ones that way.
"South America, Latin America were profoundly iodine deficient — most countries, a hundred
years ago. And the whole region, largely, is iodine sufficient now because of salt-iodization
programs. Much of Africa, much of Asia — really, it's been the primary tool in eliminating
iodine deficiency disorders around the planet."
Salt iodization is considered one of the most successful public health interventions ever,
right up there with fluoridation.
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So yay, salt iodization fixed the iodine-deficiency problem everywhere it was implemented. But
experts like Dr. Pearce are worried that we might be starting to see a little resurgence.
Why? Well one reason might be that in countries like the U.S., we're not cooking and eating
at home nearly as much as we used to.
"77% of the salt that we ingest in this country is said to be from restaurants foods or from
commercially processed foods. Those foods are typically not made with iodized salt.
So it's really only about 10-11% of the salt that we ingest which is the salt that we're
adding in cooking or adding at the table is potentially iodized. And even of that salt
in the U.S., currently only 52% of the market-share is iodized salt."
And of course one big driver of that problem is me, and maybe you — insufferable foodies
who are all obsessed these days with the fancy salts. Kosher salt, sea salt — big, crunchy
delicious non-uniform flakes that usually have little if any iodine in them. Good ol'
iodized table salt, with its tiny, uniform square crystals? This is passé. This is grandma's
salt.
In fact, I think it may have literally been decades since I regularly cooked with this
stuff or had it at the table. So why isn't my thyroid exploding out of my shirt?
Well, I do eat a lot of fish, and marine fish in particular have lots of iodine, though
it varies a lot from fish to fish. I eat a lot of bread, and some bread is baked with
potassium iodate dough conditioners to delay staling. Though most bread makers are using
bromide dough conditioners instead these days, and there's no iodine in that.
But I also eat a fair amount of dairy.
"And iodine gets into milk and other dairy foods in a couple ways. One is that the cows
have some iodine in their diet. It turns out cattle don't yield a whole lot of milk if
they're hypothyroid. Some of it is probably from the use of iodine-containing cleansers
in the dairy industry to wash off the cows, to wash off the milking equipment. And some
of that just gets absorbed across the cow's skin and secreted into milk. Some of it, probably
tiny amounts, does get into the milk supply directly from those cleansing products. And
those make dairy foods a really good source of iodine — probably our most important
source of iodine in this country right now."
But if you don't eat meat or dairy, then Dr. Pearce thinks you should definitely be trying
to use iodized salt. And guess what? If you look on the internet, you can find some fancy
flakey salts that are iodized. None of these are endorsements from me — these are just
some of the products that I found on the market when I went looking.
Dr. Pearce would also absolutely recommend that anyone who's pregnant or could become
pregnant make a concerted effort to get your iodine. And there is some data indicating
that pregnant women here in the United States are seeing some resurgence of iodine deficiency.
"And so the real concern, I think the driving concern these days, is not so much the severe
iodine deficiency that gives people the huge goiter that's visible and obvious. It's much
more subtle effects where population-level IQ may be decreased a few points, even in
regions that are only relatively mildly iodine-deficient."
You can also get iodine from a pill, of course, and most multi-vitamins, here in the U.S.
at least, have 150 micrograms, which is the recommended daily amount.
For myself, I think I'm gonna buy one of those iodized flaky salts. You do you.