Sea Salt vs. Iodized Salt: How They Compare

The difference between sea salt and iodized salt is iodine, not flavor. US iodized salt carries 45 micrograms of iodine per gram, while noniodized sea salt provides virtually no iodine, according to the NIH Office of Dietary Supplements.¹ In America’s Test Kitchen’s tests, tasters could not tell iodized from noniodized salt, and sea salt tasted no different from table salt once mixed into food.² So the choice comes down to whether you count on your salt for iodine, and to the crystal you want.

Side by side

	Sea salt	Iodized salt
What it is	Salt left behind when seawater evaporates³	Salt with added iodide; US labels must say it supplies iodide, a necessary nutrient⁴
Usual form	Fine grains to coarse crystals and flakes²	Fine table salt¹
Iodine	Not usually iodized; noniodized sea salt provides virtually no iodine¹	45 mcg per gram on US labels; measured samples average 47.5 to 50.7¹
Additives	Usually none; Morton’s fine sea salt lists only sea salt⁵	Morton iodized: calcium silicate (anticaking agent), dextrose, potassium iodide⁶
Weight per ¼ teaspoon (Morton labels)	Fine sea salt: 1.4 g⁵	Iodized table salt: 1.5 g⁶
Sodium	38.9% to 40.7% in seven sea salts measured in Switzerland⁷	About 40%, like other salts³
Taste	No difference from table salt once mixed in (ATK)²	No detectable difference from noniodized salt (ATK)²
Pickling	Fine, additive-free sea salt works; flake salt not recommended⁸	Safe, but may darken pickles⁸⁹
Price	No dated, sourced comparison found	No dated, sourced comparison found

How much iodine is in each

Salt (scope)	Iodine	Source
US iodized salt, label	45 mcg per gram (45,000 µg/kg)	NIH ODS¹
US iodized salt, measured samples	47.5 to 50.7 mcg per gram on average	NIH ODS¹
Morton iodized table salt, label	68 mcg per ¼ teaspoon (1.5 g)	Morton⁶
Swiss iodized table salt	25 mg/kg, the national fortification level since 2014	Swiss FSVO 2016⁷
Sea salts, 7 samples bought in Switzerland	Below 20 µg/kg or not detected in four; 28, 44 and 54 µg/kg in three	Swiss FSVO 2016⁷

These rows come from different labels and studies, so compare orders of magnitude, not decimals. The highest sea salt figure, 54 µg/kg, is more than 800 times lower than the US iodized label (our arithmetic). A ¼ teaspoon of Morton’s iodized salt, at 68 mcg,⁶ is close to half the adult recommended intake of 150 mcg a day (our arithmetic, from the ODS figure).¹

Why iodine matters

Iodine is an essential part of the thyroid hormones.¹ Goiter is usually the earliest sign of deficiency, and severe deficiency in pregnancy can cause major neurodevelopmental deficits in the child.¹ The adult recommended intake is 150 mcg a day, rising to 220 mcg in pregnancy and 290 mcg while breastfeeding.¹

Salt iodization programs have dramatically reduced iodine deficiency worldwide, and about 88% of households now use iodized salt.¹ US salt makers have added iodine since the 1920s, and it remains voluntary.¹ The ODS says the general US population gets enough iodine, though surveys suggest many pregnant women may not.¹

Two facts weaken salt as an iodine source in American kitchens. Most dietary salt comes from processed foods, and manufacturers almost always use noniodized salt.¹ And a cook who switches to sea salt is usually switching to a noniodized salt.¹ Seafood, eggs, milk and milk products are among the best food sources of iodine.¹ This page describes a public-health fortification program; it makes no claim that iodized salt treats any condition.

Taste

Two claims circulate: that iodine gives salt a metallic or chemical taste, and that sea salt has briny notes from its minerals. ATK’s tasters found no detectable difference between iodized and noniodized salt, and found that sea salts vary in color but only slightly in flavor.² We found no study of whether some individuals can taste iodine in salt, so that part is untested rather than disproven.

Sea salt does carry trace minerals such as magnesium, potassium and calcium.³ In the Swiss survey, six of seven sea salts had potassium below 0.05 g per kg, and the report concluded that specialty salts have no advantages over standard salts.⁷

Pickling

Pickles can be made safely with either iodized or noniodized table salt, according to the National Center for Home Food Preservation, though it recommends canning or pickling salt.⁸ Its troubleshooting guide lists iodized salt as one cause of darkened pickles, and anticaking agents as a cause of cloudy brine or sediment.⁹ It does not recommend flake salt, whose density varies.⁸ A fine sea salt with nothing added avoids both problems; see pickling salt vs. sea salt.

Can one stand in for the other?

Yes, for flavor, in any recipe. The swap changes the iodine and, by volume, sometimes the amount of salt.

Swap	Starting amount	Treatment
Either, by weight	The same weight	Computed
Iodized table salt for 1 teaspoon Morton fine or coarse sea salt	1 teaspoon (a scant teaspoon to match Morton’s labels)	Attributed (Morton products only)
Fine sea salt for 1 teaspoon iodized table salt	1 teaspoon	Attributed (Morton products only)
Flaky sea salt for iodized salt in a recipe	Weigh it; no published volume figure	Method
Iodized salt for flaky sea salt as a finishing salt	Not a good fit; by the pinch, sparingly	Method

How these were worked out. By weight: the Codex standard requires food-grade salt from any source to be at least 97% sodium chloride on a dry basis.¹⁰ By volume: Morton’s chart treats a teaspoon of its table salt as equal to a teaspoon of its fine or coarse sea salt, for Morton products only,¹¹ and its labels give 1.5 g per ¼ teaspoon for iodized table salt and 1.4 g for fine sea salt,⁶⁵ about 7% apart (our arithmetic), too little to matter in a teaspoon. Flaky salts vary too much for one figure; we found none published. These treatments follow our sea salt substitute page.

Which to use when

Iodized salt: the everyday cooking and table salt, if you rely on salt for iodine. Morton markets its iodized salt for cooking and baking.⁶
Sea salt: finishing, where ATK recommends it and its crunch shows;² fine sea salt wherever you’d use table salt.
Both: many kitchens keep iodized salt for cooking and a flaky sea salt for the table. That is a sensible split, not a tested rule.

Health notes

Sodium. Neither is lower in sodium by weight. The AHA puts table salt and most sea salts at about 40% sodium, and says a coarse sea salt has less per teaspoon only because fewer crystals fit.³ The FDA’s Daily Value for sodium is less than 2,300 mg a day.¹²
Microplastics. In a 2018 study of 39 salt brands, reported in a Greenpeace press release, contamination was highest in sea salt.¹³ That is one study of specific products, not the market.

What isn’t known

No study of whether some people can taste iodine in salt.
No figure for how much iodine US iodized salt loses in a home pantry.
No published weight per teaspoon for flaky sea salts.
No dated, sourced price comparison.

Sea salt and table salt, the full profiles
Iodized vs. non-iodized salt
Sea salt substitutes
Table salt vs. sea salt, Himalayan salt vs. table salt and kosher salt vs. sea salt
Cooking with sea salt and too much sea salt

Iodine: Fact Sheet for Health Professionals, NIH Office of Dietary Supplements. ods.od.nih.gov · Regulator ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶
Salt Types and Measurements, America’s Test Kitchen. americastestkitchen.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Sodium Sources: Where Does All That Sodium Come From?, American Heart Association, 2025. heart.org · Reference work ↩ ↩² ↩³ ↩⁴
21 CFR 100.155, Salt and iodized salt, Electronic Code of Federal Regulations. ecfr.gov · Regulator ↩
Morton Fine Sea Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³
Morton Iodized Table Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Esther Infanger and Max Haldimann, Report on the composition of prevalent salt varieties, Swiss Federal Food Safety and Veterinary Office, 2016. warwick.ac.uk · Regulator ↩ ↩² ↩³ ↩⁴
Salts Used in Pickling, National Center for Home Food Preservation, adapted from USDA Complete Guide to Home Canning. nchfp.uga.edu · Reference work ↩ ↩² ↩³ ↩⁴
Causes and Possible Solutions for Problems with Pickled Foods, National Center for Home Food Preservation. nchfp.uga.edu · Reference work ↩ ↩²
Standard for Food Grade Salt, CXS 150-1985 (rev. 2012), Codex Alimentarius. services.bis.gov.in · Standard ↩
Salt Conversion Chart, Morton Salt. mortonsalt.com · Merchant ↩
Sodium in Your Diet, U.S. Food and Drug Administration. fda.gov · Regulator ↩
Over 90% of sampled salt brands globally found to contain microplastics, Greenpeace International press release, 2018, on Kim J-S et al., Environmental Science & Technology, 2018. greenpeace.org · Publication ↩

Sea Salt vs. Iodized Salt: Iodine, Taste and When to Swap