All living organisms — bugs, trees, animals, humans — need salt to survive. But with so many different types of salt out there being touted for their different benefits, it’s logical to wonder, does it matter what kind of salt you choose?
We cover a truckload of salty science in this article — exploring four varieties of salt, concerns around microplastics and anticaking agents, salt-mining methods, and heavy metals. So let’s hit the main points up front:
The Short Version
Salt is essential for life, and especially human health. Without adequate sodium, humans get tired, crampy, and experience brain fog. If given a choice between no salt and the worst quality table salt, the savvy person takes the table salt and runs.
Don’t expect pure sodium chloride. No salt is 100% free of impurities. All commercial salts contain contaminants like heavy metals, microplastics, and anticaking agents, though some have far more impurities than others. If you want to minimize impurities, do your research into the brands you buy from.
Watch out for iodine and aluminum in table salt. Healthy people can typically tolerate higher iodine intakes than the doses found in iodized salt, but folks with thyroid disorders may want to minimize their iodized salt consumption. Many table salts also contain sodium aluminosilicate, an anticaking agent high in aluminum.
Salt contains relatively low levels of microplastics. The data suggests that inhaled microplastics (and microplastics from fruit) are more significant sources of exposure than salt microplastics. Researchers believe salt microplastics don’t pose significant health risks.
All types of salt contain heavy metals. Table salt, sea salt, and Himalayan salt come from the earth, so they all contain earth metals if they’re not refined. Researchers found concerning levels of lead in unrefined gourmet salts.
The final takeaway? The type of salt tells you a little about its safety profile, but doesn’t provide the full picture. If you consume a product daily, it doesn’t hurt to confirm the company sources and tests diligently.
As far as LMNT’s salt, we care deeply about quality. We drink LMNT ourselves daily, and we share it with our kids, parents, and friends. We make sure that every stick pack and can has a purity, quality, and consistency we can stand by as we help our community hydrate for better health. You can read about our testing here.
Ready to dig into the science behind all this? Read on.
The Long Version
If it’s not clear from that initial breakdown, no commercial salt is 100% sodium chloride — some contain other minerals and micronutrients, some contain undesirable impurities. But no matter what form it comes in, we need that sodium for our hearts to beat, muscles to contract, and nerves to fire. Still, sourcing and testing matters, and different types of salt have different tradeoffs.
With that, let’s get into the research. We’ll talk through table salt, kosher salt, sea salt, and Himalayan salt, explore studies on microplastics and anticaking agents, explain three different salt-mining methods, and share how LMNT sources salt. By the end, you’ll have the necessary information to navigate your salt purchases with less stress. But first, the basics:
Salt 101 and Why We Need It
Salt (NaCl) is a molecule made of two minerals: sodium and chloride. These electrolyte minerals power your nervous system and balance fluids throughout your body. You wouldn’t last long without them.
For example, sodium deficiency can cause brain fog, fatigue, weakness, muscle cramps, headaches, and neurological symptoms. These symptoms are common in active folks (due to sweat loss), low-carb dieters (due to higher sodium excretion), and people with various medical conditions — and severe sodium losses can lead to dangerously low blood sodium levels.
To reiterate: You need salt to live. Choosing between the worst commercial salt and ZERO dietary salt is a no-brainer. Grab that salt and start shaking!
But while your vacation Airbnb may force you to sample prehistoric table salt from parts unknown, you generally have control over your salt habits at home and can take reasonable steps to minimize any tradeoffs. Let’s get into those tradeoffs and explore four different types of salt:
Salt 1 and Salt 2: Table Salt and Kosher Salt
Ah, table salt. Cheap, ubiquitous, sourced from land or sea, and bright white. The white color comes from refinement with processing agents like chlorine and sulfuric acid, traces of which may remain in the finished product.
Kosher salt refers to salt with a larger grain size. It’s not necessarily safer, healthier, or less refined than “normal” table salt. It’s also worth noting that not all kosher salt is kosher; it’s named such because the larger grain size makes it effective at koshering meat in accordance with Jewish dietary guidelines. The large grain can sit on top of the meat and absorb fluids quickly without dissolving.
The primary difference between kosher and table salt is that table salt typically contains iodine, an essential mineral lacking in the modern diet. Consuming enough iodine can prevent a variety of health disorders (including childhood learning disabilities). ¼ teaspoon of iodized table salt contains 78 mcg of iodine, or 52% of the FDA’s recommended daily allowance (RDA) of 150 mcd/day. The safe upper limit is 1100 mcg daily, so most folks don’t need to worry if they overshoot.
Folks with thyroid disorders must be careful here, though, because getting too much iodine (even just a bit above the RDA) may result in hyperthyroidism. Because of this, we don’t put iodine in LMNT.
Moving to cons, most table and kosher salts contain anticaking agents to keep the salt from clumping (no one’s happy when the salt shaker gets stopped up). Most anticaking agents are safe for human consumption, and they’re limited to 2% of the product weight (in the US), but one anticaking agent — sodium aluminosilicate — has sparked concern recently.
In 2020, the European Panel on Food Additives and Flavorings (FAF) re-evaluated the safety of sodium aluminosilicate, which contains up to 7% aluminum, a potential neurotoxin. The FAF found that the maximum weekly exposure of aluminum from this food additive could exceed the tolerable weekly intake (TWI) of aluminum from all food sources set by the European Food Safety Authority in 2008. It would also exceed the World Health Organization’s maximum recommended levels. Given this finding, the FAF concluded that the safety of sodium aluminosilicate “could not be assessed.”
For reference, experts calculate the TWI for aluminum by finding the level that causes adverse effects in animals and then dividing by 100 — in other words, being ultra safe by recommending far below the level that’s been found to cause adverse effects. So exceeding the TWI by a few notches may not be the worst thing.
But if you want to play it safe, choose salts without sodium aluminosilicate. A well-documented safe alternative (read about the safety here and here) you may see is sodium ferrocyanide decahydrate. The potassium chloride we source for LMNT contains a small amount of sodium ferrocyanide decahydrate, but no further anticaking agents are added during the production process.
All in all? Table salt and kosher salt will do the job. Any salt is better than no salt, and you need not be stingy with the table salt shaker at the restaurant. But if you’d like to limit refinement chemicals, anticaking agents, and extra iodine, you may want to look elsewhere for an everyday option.
Salt 3: Sea Salt
Sea salt, as the name implies, is unrefined salt from the oceans. Unrefined sea salt doesn’t usually contain anticaking agents or whitening chemicals, so that’s a plus. And just like any salt, sea salt in the right amounts will hydrate you effectively.
It’s worth noting that sea salt can contain microplastics. But researchers believe microplastic consumption from salt has “negligible health impacts.” Let’s dig into that.
First, how do these microplastics get into salt? Decades of plastic manufacturing and disposal have filled the land, air, and sea with microscopic particles. Evidence for microplastics has been found in nearly every region, including allegedly clean waters like the Celtic Sea (the birthplace of Celtic Sea salt, as you might have guessed). In one 2018 study, researchers found microplastics in 25 different brands of sea salt.
In animal models, ingested microplastics have reached the brain, placenta, cell membranes, and other organ systems. In humans, inhaling microplastics causes respiratory issues; interestingly, the literature suggests that outdoor air is a MUCH larger source of microplastic exposure (500 times or more) than salt consumption. Unfiltered tap water has been shown to be a large contributor in many areas too. And perhaps surprisingly, fruits and vegetables (especially apples) can contain significantly more microplastics than salt.
Low annual exposure is one of the reasons researchers are less concerned about microplastics in salt than from other sources. Scientists have also found evidence for microplastic excretion via urine and feces in humans, but the effectiveness of these detox systems remains unclear. All in all, the science around the impacts of microplastic exposure is still emerging, and it seems safe to limit exposure — although salt doesn’t seem to be a leading contributor to microplastic ingestion.
Salt 4: Himalayan Salt
Himalayan salt typically comes from salt mines in the Punjab region of Pakistan, bordered by the Himalayan mountain range. It’s popular these days because it contains trace amounts of minerals like potassium, calcium, copper, molybdenum, iodine, zinc, cobalt, manganese, and iron (iron lends the salt its distinctive pink hue). But to get meaningful amounts of these minerals, researchers estimate you’d have to consume about 6 teaspoons of salt (13.8 grams of sodium) per day — about twice what some of the sweatiest athletes may lose through sweat. In other words, don’t rely on Himalayan salt as a trace mineral complex.
These ancient Himalayan sea beds have been dry for millions of years, but a 2022 study found terrestrial black and Himalayan salts had higher microplastic loads than marine salts. The sea beds may have been clean, but the Himalayan salt could have been contaminated by handling activities (from microfibers on clothing), atmospheric deposition (from microplastics circulating in the air), or residue from manufacturing or transportation tools.
The most common fear about Himalayan salt is heavy metal contamination. Let’s take a closer look at this concern for ALL types of salt.
Heavy Metals in Salt
Heavy metals like lead, cadmium, chromium, arsenic, and mercury can cause health issues at relatively low doses. But before hitting the panic button, it’s crucial to understand that some heavy metal exposure is the price we pay for being alive. Nothing that comes from land or sea is 100% free of impurities. If you eat a whole foods diet, some metals will enter your system — and you excrete some of them through urine, feces, and (maybe) sweat. They generally won’t accumulate to concerning levels.
That said, some salts have concerning levels of lead and mercury. Let’s explore three studies.
- Lead in unrefined ‘gourmet’ salt. A 2023 study found that unrefined salts (sea salt, Himalayan salt, black salt, and others) purchased in an Italian market contained significant amounts of lead. All ten salts exceeded European maximum permitted lead levels of 2 mg/kg by over 2x. For reference, California’s Safe Drinking Water and Toxic Enforcement Act (colloquially known as Prop 65, and with which LMNT complies), sets the acceptable daily limit of lead consumption at 0.5 mcg per day (that’s micrograms, 1/1000 of a milligram). Translation: consuming just ⅙ teaspoon daily of the “safest” gourmet salt from the Italian samples would push you about ten times past the Prop 65 lead limit.
- Heavy metals in commercial pink salt. A 2020 Australian study found heavy metals like aluminum, cadmium, and lead in 31 commercial pink salts. But only one product (a Peruvian pink salt) contained enough lead to exceed the maximum level (2 mg/kg) set by the Australian government.
- Heavy metals in table salt. A 2011 Iranian study analyzed samples of table salt for various heavy metals. On average, the levels of lead and mercury exceeded legal limits set by the Codex Alimentarius Commission, an international body charged with protecting consumer health relating to the food industry.
The takeaway is that no salt type is necessarily “completely free” from heavy metals, especially unrefined salts. To avoid concerning levels of heavy metals, you can skip the boutique gourmet salts and stick to brands that test for metals (and will share the results with you). We test each production lot of LMNT for heavy metals to ensure compliance with defined safety standards, including California’s Prop 65 requirements. You can read more about that here. Now, let’s talk salt sourcing.
Salt Sourcing Methods
How salt is sourced determines what else is included along with the sodium chloride. There are three main methods of salt sourcing:
- Blast mining
- Excavation mining
- Evaporation
Blast mining uses controlled explosions to release salt from the earth. Unfortunately, blast residue can contaminate the salt and end up in the finished product.
Excavation mining is a much gentler process that uses friction and other methods to harvest salt from the earth. There’s no blasting and no blast residue.
Finally, you can “mine” salt by evaporating salt water from the sea or salt springs. Evaporation has the lowest chance of cross-contamination with mining materials, but the salt will still contain whatever is in the sea. Some waters, of course, are cleaner than others.
LMNT’s Salt Sourcing
LMNT sources our salt through a variation of the last method, called solar evaporation. This type of evaporation entails collecting salty water in shallow pools, letting the sun evaporate the liquid, and then harvesting the salt crystals. It’s a time-tested, energy-efficient method of extracting sodium chloride from nature. Finally, we refine the salt to remove impurities like heavy metals.
To Recap
If you walk away with one thing from this article, we want it to be clear that consuming adequate sodium is better than forsaking sodium due to potential contaminants. We know for sure folks need sodium, and although some trace minerals are valuable, there is a lot of variability in trace mineral content of various salt sources, with an oftentimes concerning level of heavy metals. It is this full accounting that orients why we do what we do at LMNT. Armed with this information you should now be well-equipped to choose salt sources that meet your individual needs.
On that note, we’re laser-focused on product safety at LMNT. Besides our growing community of customers, we also give LMNT to our families every day. We wouldn’t give our loved ones a product that didn’t adhere to the most stringent standards of quality.
In other words, we give a salt. Stay Salty, everyone.
