I'm interested in using Himalayan salt. What are the health benefits with it and other specialty salts? Are there contaminants in these salts?

Answer:

Himalayan salt and other specialty or gourmet salts from ancient mineral deposits, as well as Hawaiian, Mediterranean, and French sea salts, and Australian river salts, have become popular -- due to their flavor and suggested health benefits.

One of the potential health benefits commonly ascribed to these salts is that they have higher concentrations of essential minerals (like calcium, iron, potassium, and magnesium, and chromium) than ordinary table salt (purified sodium chloride). In addition, if you have high blood pressure and are trying to limit sodium intake, these more flavorful salts may allow you to use less salt, therefore, consuming less sodium.

At the same time, there has been concern that specialty salts contain heavy metals, such as lead, cadmium, and arsenic, which are toxic compounds — although it has also been claimed that salts mined from ancient mineral deposits may contain lower amounts of heavy metals which have entered the environment due to industrialization.

To determine just how much of these minerals and heavy metals occur in specialty salts, a chemical analysis was performed by SPEX CertiPrep in 2012 on a dozen products including Himalayan Pink Fine Salt and Primordial Himalayan Salt, as well as Cyprus Black, Mediterranean Sea Salt, Sel Gris De Guerande, Aleaa Hawaiian Sea Salt, Hawaii Kai Black Salt, Murray River Pink Flake Salt, Sel de Mer, Kala Namak Black Salt, and Fumee de Sel Chardonnay Oak Smoked Salt.

The test findings
Not surprisingly, testing found that the highest concentrations of elements (both essential minerals and heavy metals) were found in the darker or deeply colored salts. Ordinary table salt, which was also tested, had the lowest amounts.

However, as noted below, amounts of essential minerals found in all salts were generally so small as to be fairly insignificant from a health perspective.

• The largest amount of calcium found in the salts was just 1.4 mg per gram of salt (1/5 teaspoon of salt). This was found in the sea salts, Cyprus Black (from the Mediterranean) and Sel Gris De Guerande Salt (from France). Although this is 7 times the amount found in table salt, it is still a tiny amount — just 0.1% of the daily adult requirement for calcium (1,000 - 1,200 mg).
• The largest amount of iron was found in Kala Namak Black Mineral Salt and was 0.5 mg per gram. This represents about 10% or less of adult daily requirement for iron, which is 8 mg for older men and women and 18 to 27 mg for younger women. However, the rest of the salts had much lower amounts of iron — 0.07 mg per gram or less.
• The largest amount of potassium was 29 mg per gram, again in Kala Namak Black Mineral Salt. But even this is an insignificant amount of potassium compared to the adult daily requirement of 4,700 mg and the amounts found in foods (1,600 mg in a single potato with skin).
• The largest amount of magnesium was found in the oak smoked salt Fumee de Sel Chardonnay, a sea salt from France, and was 8 mg. Although certainly higher than the 0.005 mg found in table salt, this is just 2% of the daily requirement of magnesium for adults, which ranges from 310 mg to 400 mg.
• The largest amount of chromium was found in Alaea Hawaiian Sea Salt and Mediterranean Sea Salt and was 2.4 mcg per gram, which is similar to what was found in table salt (2 mcg per gram). Most other salts contained about 0.5 mcg per gram. The daily requirement for adults ranges from 20 mcg to 35 mcg.

The amounts of toxic elements found were also low. However, unlike the minerals above, where large amounts are needed to make an impact, small amounts of these toxic elements raise the risk of toxicity. Here's what was found:

• Lead levels in the majority of salts tested ranged around 0.5 mcg per gram. This is the cut-off ConsumerLab.com uses when evaluating lead contamination in supplements (0.5 mcg per daily serving), which is based on the State of California's limit above which a warning label is required for pregnant women. However, this amount is not of much risk to other adults and is nearly the same as found in regular table salt (0.4 mcg). The salts with the highest levels (about 1 mcg) were black or grey salts, with the French sea salt Sal Gris De Guerande having the highest level (1.3 mcg).
• Amounts of arsenic, cadmium, and mercury were negligible in all samples. Thallium levels in most of the salts were less than 1 mcg per gram with the exception of three black and grey salts with over 1 mcg (far from a dangerous dose, which would be about 1,000,000 mcg). Vanadium was virtually undetected in all but one salt, Kala Namak Black Mineral Salt, which contained 1.9 mcg per gram — which is well below the safe upper limit of 1,800 mcg.

Odor
Most of the salts had no odor, but the researchers noted odors for the following salts: Sel Gris De Guerande ("slightly smoky odor"), Alaea Hawaiian Sea Salt ("slighltly earthy clay odor"), Sel de Mer ("slight metallic odor"), Kala Namak Black Mineral Salt ("slight sulfur smell"), Fumee de Sel Charonnay Oak Smoked Salt ("strong charred wood odor"), and Himalayan Pink Fine Mineral Salt ("slightly earthy odor").

Microplastics
Separate research has found that salt is commonly contaminated with microplastics -- small fragments and fibers of plastic from plastic pollution and manufacturing that move into the water and air. Although sea salt tends to contain the higher levels of microplastics than river salts, a study found that a Himalayan salt (mined, rock salt) purchased in the U.S. actually contained the second-highest level of microplastics, just behind one of the sea salts. However, due to the relatively small amount of salt that people consume, it is estimated that people ingest far greater amounts of microplastics from drinking water than from salt. Currently, it's not known what effects ingesting microplastics may have in people, although animal research indicates the potential for harm. (See the CL Answer about microplastics for more details).

The bottom line:
Tests of specialty salts show that although they provide higher amounts of most essential minerals as well as toxic compounds compared to table salt, the amounts of these compounds are insignificant from a health perspective. In short, it's perfectly fine to use these specialty salts, particularly if you prefer their flavors. If you want to minimize your intake of lead and other toxic elements, however, it would be best to avoid black or grey salts and stick with lighter colored salts, which, in the study above, were the two Himalayan salts, Mediterranean Sea Salt, Sel de Mer (Israel), and Murray River Pink Flake Salt.

A few words about iodine
Be aware that these specialty salts do not have added iodine. Iodine is necessary for proper functioning of the thyroid gland, which regulates metabolism in our bodies. Iodine deficiency may increase vulnerability to certain environmental pollutants, such as perchlorate. Iodine is also necessary for normal brain development in children during pregnancy and infancy. Iodine has been added to table salt since 1924 as a public health measure, to assure that people get sufficient iodine. It is not added to salt used in processed foods, leading to concerns of inadequate iodine intake among pregnant and lactating women, who are advised to supplement with an iodine-containing supplement. Although most people in the U.S. get sufficient iodine from their diets even without using iodized salt, if you exclusively use specialty salts instead of iodized salt, be sure you're getting enough iodine (good sources include fish and other seafoods as well as dairy foods and kelp supplements).