Iodized salt and sea salt are not the same product. They come from different sources, go through different levels of processing, and differ in one critical nutrient: iodine. Both are primarily sodium chloride, and both contain 40% sodium by weight, but the differences in how they’re made and what they contain have real implications for your cooking and your health.
Where Each Salt Comes From
Table salt, including the iodized variety, is mined from underground salt deposits. These deposits formed over millions of years as ancient seas evaporated and were buried under layers of earth. Once extracted, table salt goes through heavy processing to remove minerals and impurities, and manufacturers add an anti-caking agent so it flows freely from the shaker.
Sea salt is produced by evaporating current ocean water or water from saltwater lakes. It undergoes minimal processing, which is why it retains small amounts of trace minerals like magnesium, calcium, and potassium. Those minerals also give sea salt its slightly different color and flavor depending on where it’s harvested. But “minimal processing” doesn’t automatically mean healthier. The core product is the same: sodium chloride.
The Iodine Gap
This is the most important practical difference between the two. Iodized table salt in the U.S. contains about 45 micrograms of iodine per gram of salt. Sea salt, unless it’s been specifically fortified, contains less than 2 micrograms of iodine per gram. That’s roughly a 20-fold difference.
Iodine was first added to table salt in the 1920s to combat widespread thyroid problems, and it worked remarkably well. Your thyroid needs iodine to produce hormones that regulate metabolism, brain development, and growth. Adults need about 150 micrograms of iodine daily, and pregnant women need 220 micrograms. A quarter teaspoon of iodized salt provides a meaningful chunk of that requirement. The same amount of regular sea salt provides almost none.
If you’ve switched entirely from iodized table salt to sea salt and you don’t regularly eat iodine-rich foods like dairy, eggs, seafood, or seaweed, you could be falling short on iodine without realizing it. Some sea salt brands do sell iodized versions, which contain iodine levels comparable to regular table salt (around 55 micrograms per gram in one Canadian analysis), so check the label if this concerns you.
Sodium Content Is Identical
A common belief is that sea salt is lower in sodium than table salt. It isn’t. Both contain 40% sodium by weight, according to the Mayo Clinic. Gram for gram, they contribute the same amount of sodium to your diet.
There is one subtle catch, though. Because sea salt crystals are often larger and coarser than the fine grains of table salt, a teaspoon of sea salt may contain slightly less salt by weight than a packed teaspoon of table salt. This can give the impression of lower sodium, but if you measured both by weight on a kitchen scale, they’d be equivalent. If you’re watching your sodium intake, the type of salt matters far less than the total amount you use.
Crystal Size and Cooking Differences
The texture difference between the two salts is noticeable in the kitchen. Table salt has small, uniform grains that dissolve quickly and distribute evenly in recipes. This makes it reliable for baking, where precise measurements matter. Sea salt comes in a range of crystal sizes, from fine to extra coarse, and dissolves more slowly. Larger crystals are less consistent when blended into doughs or batters.
On the other hand, coarser sea salt crystals can be an advantage as a finishing salt. Sprinkled on top of food just before serving, larger flakes deliver a burst of flavor when they dissolve on your tongue. Fine salt dissolves almost instantly, while coarse crystals create a more noticeable salty crunch. Neither is better in an absolute sense; they just work differently in different contexts. If a recipe calls for “salt” without specifying, it almost always means fine table salt, and substituting coarse sea salt without adjusting the amount can leave your food under-seasoned.
Trace Minerals: Real but Minimal
Sea salt’s trace minerals are often cited as a health advantage. The minerals are real, but the amounts are tiny. You’d need to consume an enormous (and unhealthy) quantity of sea salt to get meaningful amounts of magnesium, calcium, or potassium from it. You’ll get far more of those minerals from a single banana or a handful of almonds than from all the sea salt you’d use in a day. The trace minerals do affect flavor slightly, which is a legitimate culinary reason to choose sea salt, but not a nutritional one.
Microplastics in Both Types
Because sea salt comes from ocean water, some people worry it contains more microplastics than mined salt. Research published in the Indian Journal of Community Medicine found microplastics in both commercial (processed) salt and locally produced sea salt. The sea salt samples contained roughly twice as many particles on average (14.4 per 100 grams versus 7.6 per 100 grams), but the difference was not statistically significant. Both types contained microplastics, and neither was free of them. Given how little salt you consume daily, the exposure from either source is extremely small compared to other sources of microplastics in your diet and environment.
Which One Should You Use
For everyday cooking and general health, iodized table salt is the more practical choice. It’s inexpensive, measures consistently, and provides iodine that many people don’t get enough of from other foods. Sea salt works well as a finishing salt or when you prefer its texture and flavor in specific dishes. There’s no health reason to avoid either one, but if sea salt is the only salt in your kitchen, make sure you’re getting iodine from somewhere else in your diet.