Iodized salt is a staple in every pantry. But few recipes and cookbooks mention it. Does that mean you can’t cook with it?

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Jeff from Nevada City, CA, asked, “I recently read that iodized salt is good for you, so I bought a package of Morton Iodized Salt. But it doesn’t say anywhere if I can cook with it?”

In its simplest form, iodized salt is table salt with added iodine, a mineral essential for the function of the thyroid gland—and, therefore, for our metabolism—that our body cannot produce on its own.

Iodized salt is cheap, available in every supermarket, and recommended by the Office of Dietary Supplements at the National Institutes of Health (NHS). So it shouldn’t come as a surprise it’s one of the most popular salts in the American household. (According to the NHS, 88% of households use iodized salt.)

The question is, can you cook with it?

You can cook with iodized salt, and it won’t change the smell or taste of your dish all that much. The only difference between iodized salt and non-iodized salt is the iodine content, and the two can generally be used interchangeably.

The thing about iodized salt is that, because of the iodine, it has metallic aftertaste. It just tastes differently (unless you dissolve it in water, in which case the difference becomes hard to tell).

Some find the taste of iodized salt overwhelmingly metallic compared to that of other staple salts in the household, be it kosher salt, sea salt or pink Himalayan salt. Others say the difference is negligible and that they notice no difference whatsoever.

On the other hand, you use iodized salt not because it smells or tastes better than other kinds of salt, but because it’s good for you. That’s the main reason why, when you buy iodized salt at the supermarket, it says on the label that it’s fortified with iodine.

You may be wondering how much iodine this is, exactly?

Most salts in the U.S. have about 45 mcg of iodine per 1 gram of salt, or anywhere between 1/8 and 1/4 teaspoon, depending on the brand and variety. When in doubt, refer to the nutritional information on the back of the package.

Which Other Foods Are High in Iodine?

According to the Academy of Nutrition and Dietetics’ EatRight.org, iodized salt typically contributes no more than 300 mcg of iodine to the daily diet. The best sources of iodine (other than iodized table salt) include algae, saltwater fish, and whole seafood.

An article at Medical News Today goes into more specificity and lists seaweed, cod, halibut, pollock, crab, scallops, squid, tuna (tuna steak or canned tuna), milk (whether skimmed, semi-skimmed, or whole), cheese, yogurt, and eggs as rich and natural sources of iodine.

Plants grown in iodine-rich soils can potentially be good sources of the mineral, the academy’s website says, but this is not a reliable source because we cannot know whether or not the produce we buy in grocery stores was grown in such soils.

Simply put, unless you know the soil and grow the plants yourself, it’s hard to determine whether or not they’re good sources of iodine or not.

Is Iodized Salt Kosher?

The long answer short, is “no,” iodized salt and kosher salt are not the same thing.

Iodized salt is a fine-grained salt, which most of us refer to as “table salt,” with added iodine. Kosher salt is a coarse-grained salt that’s free of additives, anti-clumping agents, and iodine to meet the strict dietary norms of traditional Jewish law.

Iodized salt is normally used as table salt for salting soups, salads, and cooked foods. In contrast, kosher salt is mainly used during cooking; most cookbook authors develop their recipes with it for its purity and texture, which is excellent for seasoning raw meat.

Are Iodized Salt and Sea Salt the Same?

No, iodized salt and sea salt are not the same thing. In fact, they are two very different kinds of salts.

Iodized salt is table salt with iodine added, and table salt is obtained from salt deposits in seas that have dried up millennia ago. Sea salt, on the other hand, is obtained by evaporating ocean water or water from saltwater lakes.

“Iodized salt is considered the most appropriate measure for iodine supplementation,” reads an excerpt from Endocrinology: Adult and Pediatric (7th Edition), 2016, available at ScienceDirect. The extract continues: “Sea salt, as usually produced, does not contain enough iodine to meet minimal human needs.”

Substituting Iodized Salt

Salt substitution is all about the size of the crystals. As you will see in the substitution ratios below, fine-grained salt is compact, so a teaspoon of it packs more saltiness than flake salt or coarse-crystal salt:

  • Substitute 1 teaspoon of fine-grained iodized salt for 1 teaspoon of non-iodized, fine-grained table salt;
  • Use 3/4 teaspoons of fine-grained iodized salt for 1 teaspoon of flake kosher salt;
  • Substitute 3/4 teaspoons of fine-grained iodized salt for 1 teaspoon of flake or coarse-crystal sea salt;
  • Use 1 teaspoon of fine-grained iodized salt for every 1 teaspoon of fine-grained sea salt.

Where Does Iodized Salt Come From?

Iodine was discovered in the beginning of the 19th century by the French chemist Jean-Baptiste Dumas. In 1811, Dumas was extracting sodium salts for the production of gunpowder when he discovered a strange violet vapor given off by algal ash while treating it with sulfuric acid.

This vapor consisted of iodine—a mineral previously unknown to man. Scientists investigated its properties further and began experimenting with its effects on humans until a Swiss physician named Jean-Francois Coindet found that giving iodine as a dietary supplement to his patients could reduce the size of their goiters.

Looking for ways to prevent goiter, governments soon concluded that the best way to supply the population with iodine was to add it to table salt, i.e., to make iodized salt, and to promote its use as generally beneficial to health.

And so, iodized salt came to be.

Why Do We Need Iodine?

Our bodies don’t produce iodine, but they need it for a number of bodily functions, the American Thyroid Association says. In particular, the thyroid gland—a small gland at the base of the neck—needs iodine to produce hormones that regulate all aspects of our metabolism.

According to information on the association’s website, iodine deficiency can lead to the development of goiter, hypothyroidism, and pregnancy-related problems, which can generally be prevented by adequate iodine intake.

In the 1920s, iodine deficiency was a common problem in the Great Lakes, Appalachian, and northwestern parts of the United States; to the point that these areas became infamous as the “goiter belt.” With the introduction of iodized salt, this issue was eliminated completely.

As for the Recommended Dietary Allowance (RDA) of iodine, the World Health Organization (WHO) recommends an intake of 150 mcg/day for adults and adolescents, 250 mcg/day for pregnant and lactating women, and 120 mcg/day for children 6 to 12 years of age.