What's up with iodized salt — Is it better for you than regular salt?

Dear Wondering,  

Great question! There are a number of different types of salt available, some of which are iodized. Iodine is a mineral that helps the thyroid function, which is critical for metabolism. Fortunately, the amount of iodine needed is minimal. In the early 1900s, people weren’t getting enough of this mineral, so there was a push to fortify salt to remedy this. While salt is a well-known source of this mineral, it’s not the only one. If your diet consists of enough other iodine-rich foods, you may be okay using the non-iodized salt you purchased.   

So, how much iodine do you need, anyway? The recommended dietary allowance (RDA) for iodine is 150 micrograms a day for adults. Because iodine is required for fetal and infant brain development, pregnant people are urged to consume about 200 to 300 micrograms per day. Iodine is found in the sea and in soil that’s previously been under the sea. Saltwater seafood (e.g., sea trout, lobster, haddock, shrimp, and shark), sea vegetables (such as seaweed, including kelp, hijiki, arame, nori, and laver), vegetables grown in soil containing iodine (found on any land that was previously under the sea), and animals grazing on plants growing in iodine rich soil all are good sources of iodine. This mineral can also be found in dairy products, such as milk and cheese, as well as fortified grains. It’s also worth noting that not all foods containing salt also contain iodine. It’s wise to be mindful about your overall salt intake during your pursuit of getting the recommended amounts of iodine, as increased sodium can affect blood pressure.     

As you can see, there are many ways to obtain iodine other than through iodized salt. That wasn’t always the case. Many years ago, when iodine wasn't as plentiful in the food supply and people relied on iodine mainly from the sea, those who lived inland were more likely to have iodine deficiency or a resulting condition called goiter. Now, food is manufactured and shipped all over the US and the world. Food containing iodine is more widely available, even for those living far from the ocean, so consuming iodized salt may not be as necessary. That being said, iodine levels in foods can vary greatly as the amount of the mineral in soil is quite variable. Therefore, fortification offers a margin of insurance that people are getting enough iodine.  

Wondering, based on your question, it sounds as though you and members of your household probably aren’t taking in much salt if your package of salt lasts such a long time. If you’re eating plenty of iodine-rich foods, you might not need to return your salt. However, if you avoid most of these foods, you may want to reconsider getting iodized salt just to be on the cautious side. If you're not sure about how to best get iodine into your diet, you may find meeting with a registered dietitian to be helpful.