| Potentially edible!|
“”...with a little help from our friend sodium chloride!
*proceeds to get stomped by Nelson*
|—Martin Prince, The Simpsons|
In New Age and holistic medical circles, certain beliefs have spread about salt. These beliefs conflict in the broad spectrum of holistic health quackery, casting humble sodium chloride in every role from nutrient panacea to "white poison".
Often this focuses on consuming the "right sort" of salt, the sort of salt that sells for $6.50 per pound.
Lots of elements
Holistically promoted salts often make the claim that they contain some ridiculous number of elements also found in the human body. This number is usually in the low 80s. All of these elements are supposedly found in the body and, by holistic medicine logic, we need all of them.
Now consider that we have 118 elements in the periodic table. 20 of those elements are artificially created with nuclear reactors, leaving us with 98 naturally occurring elements. 6 of those elements are noble gases that almost never react with anything, leaving us with 92. Of these 92 we have stuff like lead, mercury, radium, uranium, polonium, francium and other things you want to keep the hell away from your body.[note 1]
Saner chemistry tells us that 96% the body is made up of hydrogen, carbon, oxygen and nitrogen. 16 other elements make up almost all of the remaining 4%. A few dozen other elements exist in the body in traces in the parts-per-billion range. Many of these are incidental and would be toxic in any higher concentration. There's no way all 84 (or whatever number) are vital to your health and even if they were it would be foolish to depend on getting them from your salt. Himalayan Sea Salt claims to include toxic elements like plutonium, neptunium, thallium, and dysprosium, all of which are not good to eat. 
Common table salt
According to holistic medicine websites, table salt is pure evil. Because it's refined, it contributes to just about every medical condition ever. Somehow, the harmful effects of sodium chloride are totally negated by adding very small traces of other elements to it, so if you're worried about your salt, you can mix a very small pinch of mud or silt into each can of ordinary table salt and it'll transform into a remarkable superfood. Another common choice is "sea salt", which is just table salt with more impurities.
Expensive Himalayan salt has a pale pink color.[note 2] It does not actually come from the Himalayas, but from Khewra, Pakistan, some 200 miles from the actual mountain range. Chemically it's about 98 percent table salt, the remainder being mostly gypsum and iron oxide (accounting for the rusty color). Not only is it not rare, but it's from the world's second-largest salt mine system.
The claims about Himalayan salt range from overstated to extravagant, including the claim that it contains "ions of stored sunlight" and that its geometric crystalline structure is more perfect than plain salt, which will make a big difference when it dissolves on contact with any sort of water. As mentioned above, it also has claims of many weird elements claimed to "make it healthier."
Lamps constructed from Himalayan salt. Salt lamps are claimed to release special ions into the air when they contain lit candles or light bulbs. However, they are woo.
Sitting in a salt cave and breathing in the salty, dry air is supposed to be good for respiratory ailments. Maybe it works. Maybe.
Celtic Salt, also known as sel gris (gray salt) is a slightly moistened salt from clay bottomed salt basins in France. It's preferred in dishes where absorption of the food's moisture or dissolution of the salt is undesired.
Lack of salt turns people into vampires
This mostly discredited, secondhand account has been passed down to several salt woo sites by Jaques De Langre (author of Seasalt's Hidden Power) by way of very early 20th century historian Henri Pirenne (Economic and Social History of Medieval Europe).
Dr. Langre mentions in his book that "The Belgian historian Henri Pirenne observed that during the High Middle ages, the entire coast of the Atlantic was deserted and the entire continent was thrown into a Dark Age of human under-development. Historians tell us that it was caused to a great extent by the lack of salt in the human diet, the flooding of all salt flats having disabled every salt farm along the coastlines of the Atlantic Ocean and the Mediterranean Sea. The whole of Europe, therefore, suffered from a salt famine that was to last almost 500 years. The daily average ration fell to less than 2 grams per person and caused many to die from dehydration and madness. The extent of the salt famine reported by Henri Pirenne caused human flesh to be sold on the open-air markets and created an epidemic of crazed people who, to replenish their salt, drank blood from the neck artery of the person they had just slain. Quick to exploit this desperate situation for their own gain, the rulers of Europe grabbed the remnants of the salt stock and exacted exorbitant salt taxes. Heavily burdened by tariffs and gabelles, common salt became a luxury but also caused mass population shifts and exodus, lured invaders and caused wars. Mined salt from the depths of the earth was substituted, but the lack of live and balanced trace elements in rock salt lowered the mental equilibrium and intellect level almost as much as the sheer absence of salt."
But where would this mined salt come from? It would have been deposited millions of years ago from an ancient seabed, just like Himalayan salt. As for "live" elements, elements aren't alive any more than rocks and dirt are alive.
In the cooking community, it's common to see recipes calling for kosher salt, a course-ground variety of sodium chloride designed for extracting fluids from meat during the Koshering process, rather than table salt. Many people who do this say that this is because table salt contains more additives, like anti-caking agents and iodides, and accuse these of adding undesirable flavours to dishes, or of being toxins. In reality, the additives in table salt have no effect on the taste; chefs like using kosher salt because the big flakes make it easier to control. The addition of iodides to table salt was a major contributor in reducing iodine deficiency diseases in the developed world, but switching to an iodide-free salt is unlikely to do you any harm if you're eating plenty of vegetables.
Some foodies insist that different varieties of salt from various places in the world have different flavours. This is partially true; differently-shaped crystals of salt have different texture and crunch, meaning they create different sensory experiences when they are eaten in crystal form. However, in most varieties of expensive salt, the trace minerals aren't present in high enough amounts to make the salt taste of anything other than sodium chloride, and when dissolved in water there's no difference at all (besides the conspicuous consumption of using garishly-coloured salt that costs $8 a gram). There do exist some varieties of speciality salt that have different flavours, such as kala namak (which is mined from a mineral deposit containing high levels of sulfides, and is thus prized for its ability to give dishes a distinct note of rotten eggs).
In Italy, it is commonly said as a rule of thumb that pasta water should be salted until it tastes 'as salty as the sea'. This is far too much salt, and will leave your pasta inedible.  About a teaspoon of salt per litre is fine.
Serious locavores with access to a beach sometimes like to make their own salt by collecting sea water and evaporating it until the crystals form. This is an interesting home science project, but the results may not be fit for human consumption, as there is no means in the ordinary kitchen for testing the output for safe levels of contaminants. This is especially ironic if you got into DIY salt to get away from 'toxins' like iodides.
- Unless of course you want to play one hellishly nasty practical joke on the medical examiner.
- Don't confuse this with "pink salt", which is 6.25% sodium nitrate and is colored pink so as not to be confused with normal salt.
- Martin Prince, The Simpsons
- Sea Salt vs Common Table Salt, Holistic Health Library
- Thallium, The Periodic Table
- Sodium Chloride, Juicing for Health
- Himalayan Crystal Salt, Longevity Warehouse
- The Health Benefits of Sea Salt, Juicing for Health
- Salt cure, Curezone
- Kosher Salt, Wikipedia
- Ask the Food Lab: Do I need to use kosher salt?, Serious Eats
- How salty should pasta water be?, Serious Eats