Why Is There Iodine in Table Salt and Is That a Bad Thing?

I was inspired by The Kitchen Counter Cooking School, but I was wondering why you’re so against iodized table salt? Also, why is there iodine in table salt. Is this a bad thing? I’ve heard that people need a certain amount of iodine and it’s impossible to get otherwise. Is this why there is iodine in table? Any clarification would be helpful! – Sally B., Madison, Wis.

Kathleen says: Let me clarify. I’m not against iodine in salt. I’m not a fan of highly processed table salt as the natural trace elements have been stripped out. That’s why I recommend unrefined salt for home cooking instead of highly processed table salt. There are many affordable, healthier and ecologically better options out there, as I learned from the excellent book Salted by Mark Bitterman.

Unrefined or natural salts, such as mineral or sea salts, contain a variety of trace elements, often mirroring the makeup of these minerals in the body. These include magnesium and potassium, both of which help the body metabolize sodium. Bluntly put, unrefined salt has minerals that help you process the sodium better and flush out what the body doesn’t use.

Refined salt has been through an arduous chemical transformation to strip away these trace minerals to leave it pure white and pure sodium paired with an anti-caking agent and added iodine . So you get a wee bit of iodine, but none of the trace minerals that help you break down and use the sodium more efficiently. If you’ve had that container of table salt in your cupboard for more than a year, the iodine may have likely evaporated, too.

Another reader asked, “Why do they strip all the trace mineral elements out of table salt?” Only a single digit of processed salt – about 7% – is used in food or sold to consumers as table salt. The rest is sold for a wide range of industrial applications that require chemically pure sodium chloride. Pure sodium is required to make various pharmaceuticals, baking soda, fertilizer, injection-molded plastics and explosives, among other things.

Why do is there iodine in table salt in the first place? Some areas of the world, including the Great Lakes region of the United States, don’t have iodine as a naturally occurring mineral, so in the 1920s salt manufacturers began to add it to fight against disorders related to iodine deficiency, notably thyroid disorders such as goiter and cognitive development in infants and children. But not every area is deficient in iodine; for instance, South Carolina is sometimes referred to as the “iodine state.”

The World Health Organization combats iodine-deficiency by promoting iodized salt globally. In a famine setting, the lack of iodine — among many other nutrients — is a serious health issue. At that point, what salt tastes like or how much it’s refined doesn’t matter.

But in most industrialized countries where people have an adequate diet, there are other options for getting iodine. Some argue that salt isn’t the most effective way to get iodine in your system, and eating foods with iodine are a better bet.

Most dairy products contain iodine, as does seafood, kelp and seaweed, all common in Japanese cuisine. For the non-seafood eaters, you can also get iodine by eating spinach, asparagus, garlic, strawberries, lima beans, mushrooms, sesame seeds, zucchini, Swiss chard, collard greens and turnip greens. Another option is to take a multi-vitamin with iodine.

I used to advocate kosher salt, but after reading Salted, I learned that it too can be highly processed with most of the minerals stripped out. So I now recommend sea salt for daily cooking which includes important minerals that your body needs, notably magnesium, calcium, potassium, and sometimes – depending on the provenance – many more. In my kitchen, I used a variety of salts and one of my standards is Trapani’s a natural sea salt with iodine from Italy. 

Try this: Get some table salt and some sea salt. Put them in a bowl and compare the color, texture and taste. This is fun to do with friends; ask them to bring whatever salt they have at home (other than table salt) and do a comparative tasting. You don’t have to eat highly processed sodium that doesn’t taste good. Salt is used in such limited quantities in cooking, and life is short. Buy decent salt, get yourself some real flavor and extra minerals.

This story was originally published in 2012. It has been updated and may contain affiliate links.