Iodine was never removed from salt. Iodized table salt is still widely available in grocery stores, and you can buy it today just as you could in 1924. What has changed is how much of it people actually use. A combination of dietary shifts, the rise of specialty salts, and the food industry’s preference for non-iodized salt has quietly reduced iodine intake for millions of Americans, even though the fortified product never went away.
Why Iodine Was Added to Salt in the First Place
Before the 1920s, large parts of the United States were severely iodine deficient. The Great Lakes, Appalachian, and Northwestern regions were known as the “goiter belt,” where 26% to 70% of children had visibly enlarged thyroid glands. During the World War I draft, a Michigan physician examined 583 registrants and found that 30.3% had enlarged thyroids, many large enough to disqualify them from military service.
The solution was simple. Following Switzerland’s lead, the U.S. introduced iodized table salt in the early 1920s, and goiter rates plummeted. Salt was the perfect vehicle: nearly everyone used it daily, it was cheap, and iodine didn’t change the taste. The program was one of the most successful public health interventions in American history.
Salt Iodization Is Voluntary in the U.S.
Unlike many countries that mandate iodine in all salt, the United States has always kept iodization voluntary. No law requires salt manufacturers to add iodine. This means that at any point, a company can sell plain salt without it, and many do. A 2009 analysis of retail salt sales found that only 53% of table salt sold in the U.S. was iodized, well below the commonly cited estimate of 70%. The FDA does require non-iodized salt to carry a label stating, “This salt does not supply iodide, a necessary nutrient,” but that small-print warning is easy to miss.
The Specialty Salt Boom
Over the past two decades, sea salt, pink Himalayan salt, kosher salt, and other specialty salts have taken over kitchen counters and restaurant tables. These products are marketed for their texture, mineral content, or culinary prestige, but nearly all of them share one thing in common: they contain little to no iodine. Sea salt has trace amounts at best, and Himalayan salt’s much-hyped mineral profile doesn’t include meaningful iodine levels.
When you swap iodized table salt for a trendy alternative, you lose one of the easiest sources of iodine in your diet without necessarily realizing it. The shift hasn’t been driven by any health recommendation. It’s a consumer preference that carries an unintended nutritional tradeoff.
Processed Food Uses Non-Iodized Salt
Here’s the factor that matters most: Americans get roughly 70% of their sodium from processed and restaurant food, not from the shaker on the table. And the food industry overwhelmingly uses non-iodized salt. Manufacturers worry that iodine could affect the color, taste, smell, or texture of their products, reducing consumer acceptance. A systematic review found that these concerns about product quality were the primary reason food companies avoided iodized salt, even though evidence of actual taste changes is limited.
This creates an odd situation. People are eating plenty of salt, more than enough to cause health concerns about sodium intake. But the salt they’re consuming in bread, frozen meals, snacks, and fast food contributes almost no iodine. The salt that does contain iodine, the kind you sprinkle on at home, accounts for a shrinking fraction of total intake.
Iodine Levels Are Dropping
The consequences are showing up in population data. Between 2001 and 2020, urinary iodine concentrations (the standard measure of iodine status) dropped significantly across all age groups in the U.S. In children, median levels fell from 243 to 166 micrograms per liter, and the share of kids with inadequate iodine intake nearly doubled, rising from 15.4% to 27.6%. In adults, levels declined from 153 to 116 micrograms per liter, with inadequate intake rising from 15.0% to 17.9%.
The U.S. population is still considered iodine sufficient on average, but those averages mask growing pockets of deficiency, particularly among women of childbearing age and young children.
Why Iodine Matters for Your Body
Your thyroid gland needs iodine to produce the hormones that regulate metabolism, energy, and body temperature. Without enough iodine, the thyroid swells as it tries to compensate, producing the goiter that was once so common in the U.S. But the consequences go beyond a visible lump in the neck.
During pregnancy, iodine deficiency poses the most serious risks. Thyroid hormones are critical for fetal brain development, driving the formation of nerve connections and the insulation of nerve fibers. Even mild deficiency in a pregnant woman has been linked to lower verbal IQ scores in children at age 8 and reduced reading ability at age 9. Severe deficiency can cause intellectual disability and is considered one of the most preventable causes of cognitive impairment worldwide. Correcting even mild to moderate deficiency in school-age children has been shown to improve cognitive performance.
Where You Can Still Get Iodine
Iodized table salt remains the simplest source. A quarter teaspoon delivers roughly half the daily recommended intake for adults. But if you’ve moved away from table salt, other foods can fill the gap:
- Dairy: One cup of nonfat milk provides about 84 micrograms of iodine (more than half the adult daily requirement of 150 micrograms), though levels vary widely from 38 to 160 micrograms per cup depending on the brand and region. Three-quarters of a cup of plain Greek yogurt supplies around 87 micrograms.
- Seafood: Three ounces of baked cod delivers 146 micrograms, nearly a full day’s worth. Other fish and shellfish are good sources too, though amounts vary.
- Eggs: One large hard-boiled egg contains about 31 micrograms.
People who eat little dairy, avoid seafood, and use only non-iodized salt are at the highest risk of falling short. Vegans and people following restrictive diets are particularly vulnerable unless they supplement deliberately.
The Global Picture Tells a Different Story
While U.S. iodine levels have been quietly declining, much of the world has moved in the opposite direction. Mandatory salt iodization programs have been remarkably effective globally. In the WHO European Region alone, the number of countries classified as iodine deficient dropped from 23 in 2003 to just 2 in 2023. The key difference is the word “mandatory.” Countries that require all salt to be iodized, rather than leaving it up to manufacturers, have largely solved the problem.
The U.S. voluntary approach worked well when most people cooked at home with iodized table salt. It works less well in a food environment dominated by processed foods, restaurant meals, and specialty salts that contain no iodine at all.