No single sea salt is dramatically healthier than another, because all salt is roughly 95% or more sodium chloride. The differences come down to what’s in that remaining sliver: trace minerals, potential contaminants like microplastics and heavy metals, and whether the salt has been processed with additives. If you’re choosing a sea salt for health reasons, the best option is one that’s unrefined, sun-dried, sourced from clean waters, and free of anti-caking agents.
Why Sea Salt Isn’t Much Different From Table Salt
Sea salt and table salt contain comparable amounts of sodium by weight. A quarter teaspoon of table salt has about 590 milligrams of sodium, Celtic grey salt has around 500 milligrams, and Himalayan pink salt has roughly 420 milligrams. Kosher salt is the lowest at about 310 milligrams per quarter teaspoon, largely because its flaky crystals pack less densely in a measuring spoon rather than because of a fundamentally different composition.
The trace minerals that distinguish sea salts from table salt (magnesium, potassium, calcium, iron, zinc) are present in tiny amounts. Within the 1 to 1.5 teaspoons of total salt most people should limit themselves to each day, those minerals don’t add up to a meaningful nutritional contribution. You’d get far more magnesium from a handful of almonds or more potassium from half a banana than from a full day’s worth of any sea salt.
What Actually Varies Between Sea Salts
The practical differences between sea salts come down to three things: processing method, source water quality, and additives.
Sun-dried, hand-harvested sea salts retain their full spectrum of trace minerals because the gentle evaporation process doesn’t strip anything away. Table salt, by contrast, is heavily processed to remove everything except sodium chloride, then treated with anti-caking agents like calcium silicate (typically 0.2 to 0.7% of the product) or sodium ferrocyanide to prevent clumping. These additives are present at low enough levels to be considered safe, but if you prefer to avoid them entirely, unrefined sea salt is the straightforward choice.
Kiln-dried or industrially processed sea salts fall somewhere in between. High-heat drying can reduce the trace mineral content that makes unrefined salt distinctive in the first place, leaving you with something closer to table salt at a premium price.
Celtic Grey Salt and Fleur de Sel
Celtic sea salt, also called sel gris or grey salt, gets its color from the clay-lined salt ponds where it’s harvested along the coast of France. That clay contact contributes extra magnesium, calcium, potassium, zinc, and iron. Celtic salt also retains some moisture, which means each crystal contains slightly less sodium chloride by weight compared to fully dried salts.
Fleur de sel is harvested from the very top layer of salt ponds, skimmed by hand within hours of forming. It requires specific weather conditions: sunny skies, air temperature above 30°C, little to no wind, and low humidity. This delicate harvesting window is why it costs significantly more. Fleur de sel contains up to 84 trace elements and has notably higher potassium and magnesium relative to sodium chloride compared to coarser salts from the same ponds. As the harvest season progresses, the sodium chloride content of fleur de sel can drop from around 96% to 87%, with magnesium, potassium, and sulfur increasing by roughly tenfold.
Both of these salts are good options if you want the most mineral-rich, least processed sea salt available. The trade-off is price and availability.
Himalayan Pink Salt Is Not Sea Salt
Himalayan pink salt is technically rock salt, mined from underground deposits in Pakistan rather than evaporated from seawater. It contains trace amounts of the same minerals found in sea salt (magnesium, potassium, calcium, iron) and gets its pink color from iron oxide. It’s often marketed as purer than sea salt because the deposits formed millions of years ago, long before industrial pollution.
That claim has some basis. Because Himalayan salt isn’t harvested from modern oceans, it avoids one of sea salt’s biggest concerns: microplastic contamination. Both Himalayan and sea salts can contain detectable heavy metals, though, so “pure” is relative.
The Microplastic Problem
A large study published in Environmental Science & Technology tested 39 salt brands from 16 countries across six continents and found microplastic particles in the vast majority of sea salts. The range was striking: from zero to over 1,600 particles per kilogram, with one outlier exceeding 13,600 particles per kilogram. Rock salt contained far fewer, ranging from zero to 148 particles per kilogram.
Geography matters significantly. Sea salts produced in Asia contained a median of 137 microplastic particles per kilogram, compared to a median of 31 in salts from other continents. Nine of the ten most contaminated sea salt brands in the study came from Asian countries, reflecting higher levels of ocean plastic pollution in those regions.
If minimizing microplastic exposure is a priority for you, look for sea salt sourced from relatively unpolluted coastlines (parts of the Atlantic, Mediterranean, or Pacific coasts of Europe and the Americas tend to test lower) or consider Himalayan rock salt as an alternative.
Heavy Metals in All Types of Salt
When 23 salt products were sent to an EPA-certified lab for heavy metal testing, the results were sobering in one way and reassuring in another. Every single product contained detectable arsenic. Lead showed up in 96% of them. Aluminum appeared in 78%, and cadmium in 70%. Mercury was not detected in any product.
The reassuring part: none of the salts exceeded the levels that would trigger a California Proposition 65 warning based on normal daily serving sizes (with one later exception found in a 2025 update). At the small amounts of salt people consume each day, the heavy metal exposure from any of these products remains well below established safety thresholds.
This applies to all types, not just sea salt. Himalayan salt, Celtic salt, and standard table salt all showed detectable metals. The lesson isn’t to avoid salt but to recognize that “unrefined” and “natural” don’t mean “contaminant-free.” The minerals you want come packaged with trace amounts of metals you don’t.
What to Look for When Choosing
- Unrefined and sun-dried: This preserves the trace minerals that give sea salt its slight nutritional edge and avoids the anti-caking agents added to processed salts.
- Source location: Salts harvested from cleaner coastlines tend to have lower microplastic counts. European Atlantic coast salts (like those from France, Portugal, or Spain) and salts from less industrialized coastlines are generally better options.
- No additives listed: Check the ingredient label. If you see calcium silicate, sodium ferrocyanide, or silicon dioxide, the salt has been treated with anti-caking agents. A truly unrefined salt lists only salt.
- Moisture and color: A slightly damp texture or grey, pink, or off-white color signals that trace minerals haven’t been stripped. Bright white, perfectly free-flowing salt has almost certainly been heavily processed.
The Iodine Trade-Off
One genuine nutritional downside of switching entirely to unrefined sea salt is iodine. Table salt in many countries is fortified with iodine, a nutrient essential for thyroid function. Sea salt contains only trace amounts of naturally occurring iodine, nowhere near enough to meet daily requirements. If you use sea salt exclusively, make sure you’re getting iodine from other sources: seafood, dairy, eggs, or seaweed are the most reliable.
Some brands now sell sea salt with added iodine, which gives you the mineral profile of unrefined salt with the iodine safety net of table salt. This is worth considering if your diet is otherwise low in iodine-rich foods.
Putting It in Perspective
The healthiest thing you can do with any salt is use less of it. The differences between sea salt varieties are real but small, operating at the margins of nutrition. No sea salt will meaningfully boost your mineral intake, and no sea salt is free of trace contaminants. The best choice is one that’s minimally processed, sourced from clean water, and used sparingly. Celtic grey salt and fleur de sel from the French Atlantic coast check the most boxes for mineral retention and lower contamination risk, but they’re far from the only good options. Any unrefined, additive-free sea salt from a reputable source will serve you well.