Why Is Iodine Added to Salt?

Iodized salt may initially sound like a strange concept. We mostly know iodine as the brown, pungent-smelling antiseptic we use to sanitize our wounds. How can it be safe for ingestion? It turns out iodine is one of the trace minerals we need to consume on a daily basis, but most of us are deficient in it. Just like fluoride is added to water to help the public consume enough of it, iodine is added to salt for the same purpose. Today we're taking a look at iodized salt.

But before we begin our discussion about iodized salt, let's clarify the meaning of the term trace minerals. According to Brain Balance, these are minerals we must get from our diet, but only in small quantities. "The recommended daily allowance for most trace minerals is between .2 and 15 milligrams". There is a list of common trace minerals on their website, you can read it here


What is iodine?

iodine, on the periodic table

It is a trace mineral found naturally in seafood, dairy, grains, and eggs. The thyroid gland uses it to produce hormones. These hormones have a function in wound healing, tissue repair, metabolism regulation, and healthy growth. They also play a role in the regulation of body temperature, blood pressure, and heart rate. 

In some parts of the world, it is added to classic old table salt. In the US, no manufacturer is obliged by law to iodize their salt, and if they do, they don't even have to state it on the package. The reason for the fortification of salt with iodine is to prevent an illness called Goiter disease, in which the thyroid gland grows in an attempt to seek more iodine. 

History of iodine

iodine, antiseptic solution
Medical writings from as early as 3600 BC in China, show a decrease in goiter size after ingestion of seaweed. Back then, they still didn't know it was thanks to iodine. The element was officially discovered and introduced in 1813 by Joseph Louis Gay-Lussac. He sourced the word iodine from the Greek word ioeides, meaning violet-colored. The link between iodine and goiter size was made shortly after. 
Problems in the thyroid gland were most prevalent in the US around the Great Lakes and the Appalachians, far away from the ocean, where the soil was naturally poor in iodine. In these areas, as well as some Northwestern parts of the country, "26%–70% of children had clinically apparent goiter". The distribution of iodized salt became prevalent in the 1920s in the US. It started in Michigan on 1 May 1924, thanks to various reports and extensive research done on the effects of iodine on Goiters disease.  


iodine, enlarged goiter

Most of the population may be deficient in iodine to some extent, or is at risk of being deficient in it. We don't just mean in the United States- this is a global scale matter. Vegans and vegetarians are at greater risk, as well as pregnant or breastfeeding women, since they require more iodine than average. This shouldn't be cause for concern though; most of the global population won't experience symptoms as the deficiency is so mild it's almost undetectable. 

But in more severe cases, symptoms can arise and affect daily life. You can read all about them in this previous article: iodine Deficiency Is Awfully Common: Signs to Look Out For


iodine in Diet

iodine, food sources

Iodized salt is very accessible, and as much as half a teaspoon of it a day is enough to meet the daily recommended dose for iodine. But if you end up consuming more than that over the course of a day, that's fine. Any intake above the minimum is very well tolerated by the body. In fact, in order to overdose on iodine from iodized salt, you'd have to consume over 6 teaspoons of it. And by now we all know that this is far too much salt- iodized or not. 

If you don't want to use iodized salt, you can source your iodine straight from your food. It is found in abundance in seaweed, codfish, yogurt, milk, and shrimp, and some smaller amounts can also be found in eggs, canned tuna, and dried prunes. 

H/T: Healthline, Huffpost

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