Iodized salt is sold for the first time - May 1st, 1924

On this day in 1924, the first iodized salt in the U.S. went on sale at Michigan grocery stores. 

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Episode Transcript

Speaker 1 (00:00):
This Day in History Class is a production of iHeartRadio.
Hello and welcome to This Day in History Class, a
show that believes every day tastes better with a pinch
of history. I'm Gay Bluesier, and today we're talking about
the time when a few sprinkles of salt became many Americans'

(00:23):
best bet for staving off a serious and unsightly illness.
The day was May one, nineteen twenty four. The first

(00:44):
iodized salt in the US went on sale at Michigan
grocery stores. It was exactly the same as regular table salt,
save for the addition of point zero one percent of
sodium iodide five. Michigan balt companies had added the compound
to their product at the urging of the Michigan State

(01:05):
Medical Society. Many in the Great Lakes region had long
suffered from iodine deficiency, and it was hoped that adding
a trace amount of the micronutrient to salt would correct
the problem. Larger companies, such as Morton Salt weren't convinced
that the benefits of the supplement would be worth the
trouble of having to explain its presence to customers, but

(01:26):
by the end of the year Morton had come around
and iodized salt became available nationwide. Adding iodine to salt
is similar to the practice of adding fluoride to water,
both their somewhat sneaky ways to make sure the public
gets an adequate amount of a helpful mineral. Unlike fluoride, however,

(01:46):
iodine is not naturally produced by the human body. Still
its essential in small quantities in order to keep the
thyroid gland functioning properly. Without it, the thyroid is unable
to produce thyroxide, a hormone that helps maintain crucial bodily
functions such as mental acuity. So if someone doesn't get

(02:07):
enough iodine in their diet, they may start to experience
mental impairment or even develop endemic goiter, a disease characterized
by a swelling of the thyroid gland, which usually presents
as a bulbous protrusion on the side of the neck,
called a goiter. The problem is iodine isn't all that
abundant in nature, though it can be found in trace

(02:28):
amounts just about everywhere by far, though it's most prevalent
in seawater, the world's supply of which holds roughly thirty
five million tons of iodine as a result, People who
live in coastal areas rarely develop iodine deficiency, as they
absorb plenty of it just through the water and air
around them. And of course, whether you live in a

(02:50):
coastal area or not, it's easy to work iodine into
your diet by consuming food from the ocean, such as
fish or seaweed. Of course, the flip side is that
if you don't live near the ocean and don't have
access to marine foods, you are unlikely to get the
iodine you need without going out of your way for it.
That was exactly the case for many Americans in the

(03:12):
early twentieth century. Communities that were far removed from the ocean,
such as those in the interior, Northwest and the Great
Lakes region, didn't have easy access to iodine rich foods,
and thousands of residents there developed thyroid problems as a result.
In fact, the condition was so common in those inland
areas that a whole stretch of land from the Rockies

(03:35):
to the Great Lakes to western New York became widely
known as the Goiter Belt. Medical professionals had begun to
raise the alarm about iodine deficiency during the draft for
World War One, when a shocking number of men had
to be disqualified from military service due to thyroid problems.
Around the same time, a physician named David Marine conducted

(03:58):
a series of studies on other iodine deficient school children
in Akron, Ohio. He and his colleagues found that adding
a small dose of iodine to the children's water each
day greatly reduced their chances of developing a goiter. By
the early nineteen twenties, then, the link between goiters and
iodine deficiencies had been clearly established, and so too had

(04:20):
a general solution to add trace amounts of iodine to
the diets of people in high risk regions. However, there
was still the question of how exactly to do that.
Most people wouldn't be willing to buy a jar of
iodine solution and mix it into their drinking water each day,
so a different distribution method would be needed. In nineteen

(04:41):
twenty two, doctor David Murray Cowie met that demand by
proposing that iodine in the crystalline form of sodium iodide
be added to the nation's salt supply. As a professor
of pediatrics at the University of Michigan. Cowie had been
deeply troubled by the prevalence of endemic goeidter in his state,
particularly among children. His search for a solution led him

(05:05):
to the process of salt iodization, which had already proven
effective at decreasing the incidents of goiter in Switzerland. Cowie
knew that adopting the Swiss method was the US's best
shot at combating one of the major public health problems
of the day. The tough part would be getting US officials,
salt producers, and the general public to agree with him.

(05:27):
It took several months of meetings with other physicians and educators,
but eventually Cowie got approval from the Michigan State Medical
Society to endorse and implement the production of iodized salt
for the good of public health. That backing made it
much easier to get the Michigan salt companies on board
with the idea. They agreed to start producing iodized table

(05:49):
salt and the same cylindrical containers as their old product,
except now with a label that called out the addition
of sodium iodide and its health benefits. Howie also approached
Morton Salt, the nation's leading brand, about incorporating sodium iodide
into their production process as well. However, the company declined,

(06:10):
believing that a formula change might hurt their sales. As
a result, Michigan grocery stores were the first in the
country to stock iodized salt. The locally sourced product first
appeared on shelves on May first, nineteen twenty four, and
sales were about as brisk as you'd expect in estates
so widely plagued by goiters. In the months that followed,

(06:33):
many Michigan residents reported positive effects from the new miracle salt.
The buzz was so good, in fact, that Morton quickly
reversed course and joined the cause. That fall, the company
became the first to distribute iodized salt nationwide, and within
a decade, the product accounted for more than ninety percent
of the US table salt market. During that same period,

(06:56):
the number of Michiganders afflicted with goiters find well, from
a staggering thirty percent of the population to just two percent.
Those results, and others like it, became a popular selling
point for table salt, with the presence of iodine being
proudly and prominently displayed on every company's label. Morton's Salt

(07:17):
didn't stop at goiter's though, but touted other various health
benefits as well. For example, a nineteen thirty four Morton
ad proclaimed quote, taller, heavier children protected against simple goiter
are found to be superior in development iodine. By protecting
children from simple goiter exerts a remarkable beneficial effect on growth.

(07:40):
If you want your children to escape being handicapped by
this disorder, begin to use Morton's iodized salt. At once,
most Americans took that advice, but over the years, the
iodine from salt became less and less necessary. That's because
food distribution has vastly improved in the last on hundred years,

(08:00):
resulting in a much more varied diet that generally provides
all the iodine a person needs. Nonetheless, the mineral continues
to be added to nearly seventy percent of the table
salt sold in the US. Today. Iodized salt may no
longer be the necessity it once was, but as a
low cost way to prevent another goiter epidemic, it's worth

(08:22):
keeping on hand just the same. I'm Gabe Lucier, and
hopefully you now know a little more about history today.
Than you did yesterday. You can learn even more about
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(08:42):
feel free to send them my way by writing to
This Day at iHeartMedia dot com. Thanks to Chandler Mays
and Ben Hackett for producing the show, and thank you
for listening. I'll see you back here again tomorrow for
another Day in History class Pect the Future.