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salt

 
Dictionary: salt   (sôlt) pronunciation
 
n.
  1. A colorless or white crystalline solid, chiefly sodium chloride, used extensively in ground or granulated form as a food seasoning and preservative. Also called common salt, table salt.
  2. A chemical compound formed by replacing all or part of the hydrogen ions of an acid with metal ions or electropositive radicals.
  3. salts Any of various mineral salts used as laxatives or cathartics.
  4. salts Smelling salts.
  5. Epsom salts. Often used in the plural.
  6. An element that gives flavor or zest.
  7. Sharp lively wit.
  8. Informal. A sailor, especially when old or experienced.
  9. A saltcellar.
adj.
  1. Containing or filled with salt: a salt spray; salt tears.
  2. Having a salty taste or smell: breathed the salt air.
  3. Preserved in salt or a salt solution: salt mackerel.
    1. Flooded with seawater.
    2. Found in or near such a flooded area: salt grasses.
tr.v., salt·ed, salt·ing, salts.
  1. To add, treat, season, or sprinkle with salt.
  2. To cure or preserve by treating with salt or a salt solution.
  3. To provide salt for (deer or cattle).
  4. To add zest or liveliness to: salt a lecture with anecdotes.
  5. To give an appearance of value to by fraudulent means, especially to place valuable minerals in (a mine) for the purpose of deceiving.
phrasal verbs:

salt away

  1. To put aside; save.
salt out
  1. To separate (a dissolved substance) by adding salt to the solution.

idioms:

salt of the earth

  1. A person or group considered as the best or noblest part of society.
worth (one's) salt
  1. Efficient and capable.

[Middle English, from Old English sealt.]


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How Products are Made: How is salt made?
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Background

Salt is the common name for the substance sodium chloride (NaCI), which occurs in the form of transparent cubic crystals. Although salt is most familiar as a food supplement, less than 5% of the salt produced in the United States is used for that purpose. About 70% is used in the chemical industry, mostly as a source of chlorine. Salt is also used for countless other purposes, such as removing snow and ice from roads, softening water, preserving food, and stabilizing soils for construction.

The earliest humans obtained their salt from natural salt concentrations, called licks, and from meat. Those people who lived near the ocean may have also obtained it by chewing seaweed or from the natural evaporation of small pools of seawater. Meat became a more important source of salt as hunting was developed, as did milk when sheep, goats, horses, camels, reindeer, and cattle were domesticated. Even today, certain peoples—such as the Inuit of the far north, the Bedouin of the Middle Eastern deserts, and the Masai of east Africa—use no other form of salt.

As agriculture developed, leading to an increased population and a diet consisting mostly of plants, it became necessary to devise ways of obtaining salt in greater amounts. The earliest method of salt production was the evaporation of seawater by the heat of the sun. This method was particularly suited to hot, arid regions near the ocean or near salty lakes and is still used in those areas. Solar evaporation was soon followed by the quarrying of exposed masses of rock salt, which quickly developed into the mining of underground deposits of salt. Two thousand years ago the Chinese began using wells to reach underground pools of salt water, some of which were more than 0.6 miles (1.0 km) deep.

In areas where the climate did not allow solar evaporation, salt water was poured on burning wood or heated rocks to boil it. The salt left behind was then scraped off. During the time of the Roman empire, shallow lead pans were used to boil salt water over open fires. In the Middle Ages these were replaced with iron pans which were heated with coal. In the 1860s a procedure known as the Michigan process or the grainer process was invented, in which salt water was heated by steam running through pipes immersed in the water. This process is still used to produce certain types of salt. By the late 1880s open pans were replaced by a series of closed pans, in a device known as a multiple-effect vacuum evaporator, which had been used in the sugar industry for about 50 years.

Today the United States is the world's largest producer of salt, followed by China, Russia, Germany, the United Kingdom, India, and France.

Raw Materials

Salt is obtained from two sources: rock salt and brine. Rock salt is simply crystallized salt, also known as halite. It is the result of the evaporation of ancient oceans millions of years ago. Large deposits of rock salt are found in the United States, Canada, Germany, eastern Europe, and China. Sometimes pressure from deep inside the Earth forces up large masses of rock salt to form salt domes. In the United States, salt domes are found along the Gulf Coast of Texas and Louisiana.

Brine is water containing a high concentration of salt. The most obvious source of brine is the ocean, but it can also be obtained from salty lakes such as the Dead Sea and from underground pools of salt water. Large deposits of brine are found in Austria, France, Germany, India, the United States, and the United Kingdom. Brine may also be artificially produced by dissolving mined rock salt or by pumping water into wells drilled into rock salt.

Natural brines always contain other substances dissolved along with salt. The most' common of these are magnesium chloride, magnesium sulfate, calcium sulfate, potassium chloride, magnesium bromide, and calcium carbonate. These substances may be as commercially valuable as the salt itself. Rock salt may be quite pure, or it may contain various amounts of these substances along with rocky impurities such as shale and quartz.

For table salt, however, additives are usually mixed in. Most table salt is iodized in order to provide the trace element iodine to the diet. This helps to prevent goiter, a disease of the thyroid gland. To supply iodine, a small amount of potassium iodide is added. Table salt also contains a small amount of various chemicals used to keep the salt from absorbing water and caking. These chemicals include magnesium carbonate, calcium silicate, calcium phosphate, magnesium silicate, and calcium carbonate.

The Manufacturing
Process

Processing rock salt

  • Underground salt deposits are usually discovered by prospectors searching for water or oil. When salt is detected, a diamond-tipped, hollow drill is used to take several regularly spaced core samples throughout the area. These samples are analyzed to determine if salt mining would be profitable.
  • When a site is selected for mining, shafts are sunk into the center of the salt deposit. Then a machine that looks like a gigantic chain saw is used to cut a slot about 6.0 inches (15 cm) high, about 66 feet (20 m) wide, and about 10 feet (3 m) deep into the salt at floor level. This process is known as undercutting. A series of holes are drilled into the undercut salt with an electric drill containing a tungsten carbide bit. These holes are filled with an explosive such as dynamite or ammonium nitrate. Electric blasting caps connected to long wires are attached, and the explosive is detonated from a safe distance. Cutting and blasting are repeated in a pattern that leaves pillars of salt standing to support the roof of the mining area. This is known as the room-and-pillar method and is also used in coal mines.
  • Chunks of blasted rock salt are transported to an underground crushing area. Here they are passed over a grating known as a grizzly which collects pieces smaller than about 9 inches (23 cm). Larger pieces are crushed in a rotating cylinder between metal jaws with spiked teeth. The salt is then transported outside the mine to a secondary crushing area where a smaller grizzly and a smaller crusher reduce the particle size to about 3.2 inches (8 cm). At this point foreign matter is removed from the salt, a process known as picking. Metal is removed by magnets and other material by hand. Rocky material may also be removed in a Bradford breaker, a rotating metal drum with small holes in the bottom. Salt is dumped into the drum, breaks when it hits the bottom, and passes through the holes. Rocky matter is generally harder than salt, so it does not break and does not go through. The picked salt then goes to a tertiary crushing area, where an even smaller grizzly and crusher produce particles about 1.0 inch (2.5 cm) in size. If smaller particles are needed, the salt is passed through a grinder consisting of two metal cylinders rolling against each other. If purer salt is needed, rock salt is dissolved in water to form brine for further processing. Otherwise the crushed or ground salt is passed through screens to sort it by size, poured into bags, and shipped to the consumer.

Processing brine

  • The simplest method of evaporating brine is solar evaporation, but it can only be used in hot, dry, sunny places. The brine is collected into shallow ponds and allowed to evaporate in the sun. Insoluble impurities such as sand and clay and slightly soluble impurities such as calcium carbonate settle to the bottom as evaporation begins. The brine is pumped or moved by gravity flow to another pond where calcium sulfate settles out as evaporation continues. The remaining brine is moved to yet another pond where the salt settles out as evaporation proceeds. The brine is moved one more time before evaporation is complete to prevent highly soluble impurities such as magnesium chloride, magnesium sulfate, potassium chloride, and magnesium bromide from settling out with the salt. These substances may be collected separately for commercial use.
  • The salt is scooped up by machines running on temporary railroad tracks laid on top of the layer of salt. It is then washed with highly concentrated salt water. This water contains so much salt that it cannot hold any more, so the salt is washed free of any trace impurities without dissolving. The washed salt is removed from the salt water, rinsed with a small amount of fresh water, and piled into huge stacks to drain for two or three months. At this point the salt is about 99.4% pure and can be used for many industrial purposes. If purer salt is needed, it is rewashed in salt water and fresh water, allowed to drain for one or two days, then dried in a hot air oven at about 365°F (185°C). This salt is about 99.8% pure and can be used for food processing.
  • Most brine is processed by a multiple-effect vacuum evaporator. This device consists of three or more closed metal cylinders with conical bottoms. Brine is first treated chemically to remove calcium and magnesium compounds. It then fills the bottom of the cylinders. The brine in the first cylinder passes through tubes heated by steam. The brine boils and its steam enters the next cylinder, where it heats the brine there. The steam from this brine heats the brine in the next cylinder, and so on. In each cylinder the condensation of steam causes the pressure inside to drop, allowing the brine to boil at a lower temperature. Salt is removed from the bottom of the cylinders as a thick slurry. It is filtered to remove excess brine, dried, and passed through screens to sort the particles by size. Salt made this way is known as vacuum pan salt and consists of small cubic crystals.
  • Brine may also be processed in a grainer. The brine is chemically purified and pumped into a long open pan heated by steam running through pipes immersed in the brine. The brine is heated to a temperature slightly below the boiling point and flakes of salt form on its surface as it evaporates. Usually a temperature of about 194°F (90°C) is used. Lower temperatures produce larger flakes and higher temperatures produce smaller flakes. The flakes grow until they sink to the bottom of the pan, where they are collected and dried. Grainer salt consists of small flakes rather than cubes and is preferred for certain uses in food processing. Sometimes the Alberger process is used, in which the brine is first partially evaporated in a vacuum evaporator then moved to a grainer. This process produces a mixture of flakes and cubes.
  • At this point salt used for most purposes is ready to be packaged in bags or boxes and shipped to consumers. To make iodized table salt, however, potassium iodide is added, then magnesium carbonate, calcium silicate, calcium phosphate, magnesium silicate, or calcium carbonate is added to make it free-flowing. The salt is then packaged and shipped to restaurants and grocery stores.

Quality Control

Specifications for salt vary widely according to the intended use. Salt intended for human consumption must be much purer than salt used for melting snow and ice, but salt used for certain scientific purposes may need to be even purer.

For most purposes, rock salt is allowed to have a gray, pink, or brown tinge rather than being pure white. The impurities that cause these colors may make up as much as 4% of a test sample. To test solubility, a 0.7-ounce (20 g) sample is placed in 6.8 fluid ounces (200 ml) of water. It should completely dissolve in no more than 20 minutes.

Evaporated salt intended for food processing is very pure, containing as much as 99.99% sodium chloride before additives are mixed in. This is important not only for safety and good taste, but because certain impurities can cause problems with certain foods. For example, small amounts of calcium tend to toughen vegetables. Traces of copper or iron tend to destroy vitamin C and to increase the rate at which fatty foods become rancid. In addition, calcium and magnesium both tend to make salt absorb more water, causing it to cake.

Health Aspects

Salt intake—or more precisely, sodium intake—is a controversial topic in health care today. Healthy adults can safely consume 0.2-0.4 ounces (6-11 g) of salt daily, which is equivalent to 0.08-0.14 ounces (2400-4400 mg) of sodium. For some people with high blood pressure, salt intake should be reduced. About one-third to one-half of all hypertensive people are salt-sensitive and will benefit from a low-sodium diet. Since there is no way to tell who these people are, most hypertensives under medical care will be placed on such a diet to see if it helps. A low-sodium diet usually aims to reduce sodium intake to less than 0.08 ounces (2400 mg) per day. While some have suggested that everyone should reduce salt intake, others point out that there is no evidence that salt restriction is of any benefit to otherwise healthy individuals.

Where To Learn More

Books

Adshead, Samuel A.M. Salt and Civilization. MacMillan, 1992.

Multhauf, Robert P. Neptune's Gift. Johns Hopkins, 1978.

Periodicals

Dornberg, John. "A 700-Year-Old Mine in Poland Is a Shrine to Human Ingenuity." Smithsonian, March 1994, pp. 96-106.

Vogel, Hans Ulrich. "The Great Well of China." Scientific American, June 1993, pp. 116-21.

Young, Gordon. "The Essence of Life: Salt." National Geographic, September 1977, pp. 380-401.

[Article by: Rose Secrest]


 

The chemical compound sodium chloride. It is used extensively in the food industry as a preservative and flavoring, as well as in the chemical industry to make chlorine and sodium. See also Chlorine; Food preservation; Salt (chemistry); Sodium.

Salt was originally made by evaporating sea water (solar salt). This method is still in common usage; however, impurities in solar salt make it unsatisfactory for most commercial uses, and these impurities also lead to clumping. Salt, freshly produced from sea-water evaporation ponds, may contain large numbers of halophilic (salt-loving) microorganisms. In the United States refined salt is obtained from underground mines located in Michigan and Louisiana. Salt is usually handled during the refining processes as brine.

Salt is liable to clumping during periods of high humidity, so preventives are added. Materials used include magnesium carbonate and certain silicates. Iodides are added in those areas where iodine deficiencies exist.


 

(1) (Speech Application Language Tags) Extensions to HTML, XHTML and XML for voice recognition and synthesized speech and audio output. SALT is designed to support mixed modes including audio, video, text and graphics, depending on the device in the user's hands. For more information, visit the SALT Forum at www.saltforum.org.

(2) (salt) In cryptography, a random number that is added to the encryption key or to a password to protect them from disclosure. See cryptography.

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Salt has always been an important commodity, especially in hot climates, where salt loss through the sweat can be considerable. Soldiers of the Roman legions were often paid part of their stipend in salt — the so-called salerium argentinium, giving us the word salary.

Salts in general are formed, together with water, when acids react with bases, but the common meaning of ‘salt’ refers in particular to sodium chloride, the same material that is found in salt cellars. Normal saline is a solution of salt in pure water containing 0.9 g of sodium chloride per 100 ml. This solution is often used for bathing and cleaning wounds, or given by intravenous infusion after excessive blood loss — but why is it called ‘normal’? It is because the solution has the same tonicity as blood. Tonicity is a term related to osmotic strength, a property determined by the total number of molecules or ions in a given volume of solution. If living cells are bathed in a hypertonic saline (with a greater tonicity than normal saline) then the cells shrink and cease to function properly, as water passes outwards from the cells into the concentrated solution. Conversely, if living cells are bathed in hypotonic saline (lower tonicity than normal saline) they swell, water passing from the dilute solution into the cells, and eventually the cells may burst. Thus fluids that exist in different body compartments must be of the same tonicity, to avoid any such shrinkage or swelling. Salt — that is, sodium chloride — is one of the most important salts used by the body to keep fluids at their correct osmotic strength.

In a 70 kg person, the extracellular fluid contains an amount of sodium ions equivalent to 125 g of salt, while in the intracellular fluid — the sum total inside all body cells — there is the equivalent of 25 g of salt. With an average urine output of 1 litre per day there is a loss of about 9 g of salt per day. The kidneys filter off from the blood the equivalent of around 1500 g/day of salt, of which 99.5% is reabsorbed as the filtrate passes down the kidney tubules, so that only 0.5% ends up in the urine. There are also small losses of salt in the saliva and faeces, and during strenuous exertion — particularly in a hot environment — there is significant salt loss through the sweat. Clearly the salt loss must be made up by dietary intake, but this alone is not sufficiently precise to keep the tonicity of body fluids constant. Therefore the body has control mechanisms to regulate salt levels, by either increasing or reducing its excretion. If the intake of salt is insufficient, keeping the concentration correct causes the extracellular fluid volume to decrease, with consequent dehydration.

As with most bodily control mechanisms, there is a system for dealing with deficiency as well as one for dealing with excess. They are, respectively, the renin-angiotensin system and atrial natriuretic peptide.

When the body is short of salt the extracellular fluid volume, including the circulating blood volume, decreases, and the blood pressure may fall; the sodium concentration falls and the potassium ion concentration may rise, especially in those eating a low sodium diet. All these changes act directly or indirectly as stimuli for the release of the enzyme renin in the kidneys, triggering a sequence of chemical events in the blood of which the end product is angiotensin II. This is a powerful constrictor of blood vessels and therefore counteracts any fall in blood pressure. Many people with hypertension are treated with drugs which block the enzyme required for angiotensin II formation. (This same converting enzyme also breaks down kinins, which are powerful vasodilators, and therefore tend to lower the blood pressure. When kinins are preserved by inhibiting the converting enzyme, the decrease in blood pressure is probably due to both a lack of angiotensin II and also an excess of kinins.)

Angiotensin II also acts on the adrenal cortex to liberate aldosterone, which in turn causes the kidneys to increase the reabsorption of sodium ions from the filtered fluid.

When salt intake is excessive, the extracellular fluid volume and the blood pressure rise; stretching of the atria of the heart causes the release of stored granules that contain atrial natriuretic peptide. As the name implies (natrium; sodium: ouron; urine) this peptide causes natriuresis; that is, it acts on the kidneys to increase salt loss in the urine by reducing its reabsorption. More water is lost along with the salt, so the excess fluid volume is corrected.

In man excess salt intake has been considered to cause hypertension, but the supporting evidence is equivocal. Certainly there are salt-sensitive strains of laboratory animals that become hypertensive when fed salt, but other strains do not. In the animal kingdom low salt content of the diet is a problem. In seed-eating birds, like parrots, the seeds contain very little salt and an avid salt retaining mechanism has developed in the terminal part of the gut, the coprodaeum, so that little or no salt is lost in the faeces. Similarly, in frogs and toads, salt is avidly reabsorbed from the bladder, so that urine is free of salt. Darwin described how some primitive peoples would pick up a large toad (Bufo marinus), gently squeeze it, and be rewarded with several fluid ounces of almost pure water.

The old medical name, from the time when prescriptions were written in Latin to prevent patients knowing what they were getting, is nat. mur., standing for natrium of muriate. Muriatic acid is hydrochloric acid, therefore nat. mur. is the chloride salt of natrium — that is, sodium. Many popular homeopathic remedies of today contain nat. mur. in infinitesimally low amounts. The reader may ponder how adding such miniscule amounts of salt to the very large quantities already present in the body can have any effect whatsoever.

— Alan W. Cuthbert

See also blood pressure; body fluids; kidneys; sweating; water balance.

 

Usually refers to sodium chloride, common salt or table salt (chemically any product of reaction between an acid and an alkali is a salt). The main sources are either mines in areas where there are rich deposits of crystalline salt, or deposits left by the evaporation of sea water in shallow pans (known as sea salt). See also sodium; buffers.

 

A member of a wide range of chemicals formed when one or more hydrogen atoms of an acid has been replaced by a metal. Salts are usually crystalline at normal temperatures and dissolve in water to form positive and negative ions. Salts such as sodium chloride, calcium carbonate, and potassium chloride are common in the body. They play vital roles in physiological functions such as nerve conduction and muscle contractions. The term salt is often used to refer to sodium chloride, the most common type of salt (see table salt).

 

Today salt is inexpensive and universally available, but that wasn't always the case. Because of its importance in food preservation and the fact that the human body requires it (for the regulation of fluid balance), salt has been an extremely valuable commodity throughout the ages. It was even once used as a method of exchange-Roman soldiers received a salt allowance as part of their pay. Salt was valued by the ancient Hebrews and Greeks, throughout the Middle Ages and well into the 19th century when it began to become more plentiful and therefore reasonable in price. Salt (sodium chloride) comes either from salt mines or from the sea. Most of today's salt is mined and comes from large deposits left by dried salt lakes throughout the world. Table salt, a fine-grained refined salt with additives that make it free-flowing, is mainly used in cooking and as a table condiment. Iodized salt is table salt with added iodine (sodium iodide)-particularly important in areas that lack natural iodine, an important preventative for hypothyroidism. Kosher salt is an additive-free coarse-grained salt. It's used by some Jews in the preparation of meat, as well as by gourmet cooks who prefer its texture and flavor. Sea salt is the type used down through the ages and is the result of the evaporation of sea water-the more costly of the two processes. It comes in fine-grained or larger crystals. Celtic salt is natural, solar-evaporated sea salt that's been hand-harvested, from the Atlantic marshes in Brittany, France, using a 2,000-year-old Celtic tradition. It has a mellow, sweet-salty flavor. Rock salt has a grayish cast because it's not as refined as other salts, which means it retains more minerals and harmless impurities. It comes in chunky crystals and is used predominantly as a bed on which to serve baked oysters and clams and to combine with ice to make ice cream in crank-style ice-cream makers. Pickling salt is a fine-grained salt used to make brines for pickles, sauerkraut, etc. It contains no additives, which would cloud the brine. Sour salt (see citric acid), also called citric salt, is extracted from acidic fruits, such as lemons and limes. It's used to add tartness to traditional dishes like borscht. Seasoned salt is regular salt combined with other flavoring ingredients, examples being onion salt, garlic salt and celery salt. Salt substitutes, frequently used by those on low-salt diets, are products containing little or no sodium.

 
Thesaurus: salt
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also salt away

noun

    A person engaged in sailing or working on a ship: jack (uppercase), jack-tar, mariner, navigator, sailor, sea dog, seafarer, seaman. Informal tar. Slang gob3. See sea.

phrasal verb - salt away

  1. To reserve for the future: keep, lay aside, lay away, lay by, lay in, lay up, put by, save (up), set by. See keep/release, save/waste.
  2. To place (money) in a bank: bank2, deposit, lay away. Informal sock away. See keep/release, money.

 
Antonyms: salt
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n

Definition: food seasoning
Antonyms: pepper


 
Hacker Slang: salt
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A tiny bit of near-random data inserted where too much regularity would be undesirable; a data frob (sense 1). For example, the Unix crypt(3) man page mentions that “the salt string is used to perturb the DES algorithm in one of 4096 different ways.


 
(sôlt)
n

A compound of a base and an acid; a compound of an acid, some of the replaceable hydrogen atoms of which have been substituted.

 

Chemical compound formed when the hydrogen of an acid is replaced by a metal or its equivalent, such as ammonium (NH4). Typically, an acid and a base react to form a salt and water. Most inorganic salts ionize (see ion) in water solution. Sodium chloride — common table salt — is the most familiar salt; sodium bicarbonate (bicarbonate of soda), silver nitrate, and calcium carbonate are others.

For more information on salt, visit Britannica.com.

 

Condiment used in biblical times for a variety of purposes: in the sacrificial ritual, in medicine, and as a preservative for food. Every sacrifice was to be sprinkled with salt (Lev. 2:13) and the Temple housed a salt chamber. Newborn infants were rubbed with salt, apparently as a health measure (Ezek. 16:4). Because of its preservative quality, an everlasting covenant is described as a "covenant of salt" (Num. 18:19). When the Prophet Abijah wishes to describe God's promise that the House of David will rule over Israel forever, he calls the promise "a covenant of salt" (II Chr. 13:4,5).

The lasting effect of salt probably accounts for its use by the prophet Elisha as a means for purifying the waters of Jericho when he was told by the local townspeople that the "water was bad and caused miscarriage" (II Kings 2:19-22). On the other hand, salt was strewn on the land of a town by a conqueror in order to render it permanently barren (Judg. 9:45).

Among the Dietary Laws ordained by the Halakhah is the procedure for draining blood from meat before it is cooked by salting it thoroughly. The halakkah requires that a little salt be sprinkled on the bread eaten at the beginning of a meal before a benediction is recited over it. This is popularly explained as a symbolic act, since a man's table in post-Temple times serves as a substitute for the altar where sacrifices were salted.


 

The belief that spilling salt brings bad luck (especially, a quarrel between friends) was first noted in the 16th century, and is widely known today; to avert the evil, one should take a pinch of the spilt salt with the right hand and throw it over the left shoulder—into the fire, according to older sources, or ‘to blind the Devil’, as is now sometimes said. To explain this belief, some people claim that Judas spilt the salt at the Last Supper, but the symbolic role of salt in folklore is strong enough to account for it.

Just as it keeps food wholesome, so salt was used to repel spiritual and magical evil, both in Catholic ritual and in folk practice, and as a symbol of incorruptibility and virtue (Matthew 5: 13). The use of salt as magical protection is recorded from various parts of England, though less regularly than in Scotland and Wales. A handful thrown into the fire would torment witches and drive them away; in Lancashire this had to be done for nine successive mornings, with the words: ‘Salt, salt! I put thee into the fire, and may the person who has bewitched me neither eat, drink, nor sleep, till the spell is broken’ (Harland and Wilkinson, 1873: 235).

A widespread custom in the days when the dead were laid out at home was to put a plate of salt on the chest of the corpse, and keep it there till the funeral; in Cumberland in the early 20th century it was ‘almost universal among the poorer classes’ (Folk-Lore 31 (1920), 154), and the same was probably true elsewhere. The reason, it was generally said, was to prevent the body swelling; however, the salt might once have been regarded as a magical defence against evil spirits, or against the possibility of the ghost walking.

Like bread and coal, salt is one of the appropriate token gifts brought when first footing on New Year's Day, or given to a new baby, or brought into a new house; in these cases it represents prosperity.

Bibliography
The full bibliography list is available here.

  • Opie and Tatem, 1989: 338-44
  • Radford; Radford, and Hole, 1961: 297-9
  • Roud, 2003: 387-93
 

A chemical compound formed when the hydrogen of an acid has been replaced by a metal. A salt is produced, together with water, when acid reacts with a base. Salts such as sodium chloride, calcium carbonate, and potassium chloride are common in the body and play vital roles in body functions, such as conduction of nerve impulses and the production of muscle actions.

 

As a commodity of near universal demand, common salt, or sodium chloride, has been produced and traded on a large scale in most countries throughout history. As a national industry in the United States, salt production can be studied in three distinct phases. First, salt served as a vital commodity drawn from oceans and surface waters by boiling. Second, producers discovered rock salt deep beneath the earth's surface and began large scale drilling operations. Finally, the salt industry moved into the realm of high technology as producers scientifically derived compounds from raw materials, reducing salt to—and marketing it as—its component chemicals.

Salt production in America dates from before colonial settlements, and it was vital to those settlements as a preservative and curing agent for perishable meats and other goods. The British colonies were well situated to produce sea salt; however, although there were saltworks at the Jamestown and Plymouth colonies, they were costly operations, and colonists therefore largely tended to import salt. During the American Revolution there was a frantic, and largely successful, attempt to produce salt on the American coast, either by the solar evaporation of sea-water in lagoons laid out along the shore or, more commonly, by boiling it down in cast-iron pots. With the end of the war, these establishments became unable to compete economically with salt imported from England or the West Indies, and the United States again became a salt importer.

As settlement moved west and away from the coastline, inland sources of salt became more cost effective. Interior America possessed many brine springs, known as "licks" because wild animals, especially buffalo, congregated around them to lick the salt deposits. Buffalo trails to these licks became some of the first roads beyond the Appalachians. Many licks were known to the French, who largely controlled that region. Among the first salt-lick regions the British settlers appear to have paid attention to was the Onondaga country of central New York. French travelers reported that Indians were making a little salt there in the mid-eighteenth century, and, in 1788, the Anglo-Americans began to manufacture salt near present-day Syracuse, New York. A little later, buffalo licks gave rise to salt production from brine at two localities now known as Saltville, Virginia, and Charleston, West Virginia. Saltworks began as early as the late 1770s in the Kentucky settlements and quickly became a cornerstone of the frontier economy. Salt making employed scores of landless workers, and the salt produced became a vital currency in the cash-poor region. As late as the 1870s, salt was produced from buffalo licks in Kansas.

As in Europe, salt was regarded as important enough in the United States to justify government intervention, and most salt-producing lands were reserved to the states, which leased them to private producers. The state of New York provided brine to producers and applied a tax, which became a major source of funds for construction of the Erie Canal. Salt production from brine began on the Scioto River in Jackson County, Ohio, before 1800, and when the state was organized in 1803, the area was set aside as a state reservation. On the Wabash, near Shawnee-town, Illinois, the federal government actually took on the operation of a saline works in the early nineteenth century. As salt proved plentiful, however, interest of governments waned. Salt exploration in Michigan began in 1838 under state auspices, but the actual production that began in 1860 was entirely private.

Salt became plentiful as a result of the discovery of rich in-ground sources at great depths. Salt production by well drilling appeared in the United States in the early nineteenth century in Kanawha country near present-day Charleston, West Virginia, through the effort of brothers David and Joseph Ruffner. From 1806–1808, their success in finding strong brine ninety-eight feet below the earth's surface made Kanawha a leading salt-producing region. Many other wells followed. By 1835, forty furnaces in the region boiled down brine, and, by 1845, one well reached 1,500 feet deep.

After reaching production of 2 million bushels (1 bushel equals 56 pounds) a year by 1850, Kanawha's output declined. Onondaga's output similarly declined after reaching 9 million bushels in 1862 and again dropped drastically after 1883. At that time, salt production began in Wyoming County, New York, from a deep well drilled originally in search of oil. Rock salt was found, however, and was produced at various places in New York from 1886.

Rock salt was not always deep, and it is now known that Indians mined salt at several shallow deposits in the Far West. During the emergency conditions of the Civil War, the Confederate government began to work a salt spring in Louisiana, and, in 1862, rock salt was found at a depth of only sixteen feet. Large-scale mining began, only to be terminated by the destruction of the works by Union troops in April 1863. Mining has been continuous at Avery Island since 1883.

Deep salt strata can either be mined or, often more economically, turned into brine by adding water. Michigan's salt production began in 1860 with a 636-foot well at East Saginaw. Near Hutchinson, Kansas, rock salt was found in 1887 by drilling to 800 feet. Drilling has also uncovered salt deposits in many other states—so many, in fact, that salt has lost its status as a precious commodity.

Since the 1850s, one of the most important sources of salt in the United States has been the tideland of San Francisco Bay. Here, solar salt production is successfully accomplished by a method practiced in France since the Middle Ages. Seawater is admitted to enclosed, rectangular basins and transferred to smaller and smaller enclosures as the sun reduces its volume. Ultimately, the water evaporates leaving the salt deposits.

Up to the mid-nineteenth century, nearly all salt was produced for human and animal consumption, although about half was used in meatpacking. In England, large quantities were used in making artificial soda, or sodium carbonate. This industry came to the United States in 1882 and, by 1900, consumed about half of the salt used in the country. By 1957, nearly 80 percent of salt consumed in the United States went to the chemical industry, and the artificial soda industry became the primary user in industries based on sodium and chloride, the elemental constituents of salt. Uses of sodium include the manufacture of caustic soda (sodium hydroxide), which is, in turn, used to make the artificial fiber rayon, to produce aluminum, and to manufacture plastics and detergents. The chlorine-consuming industries are even newer, although they depend on the mid-nineteenth-century discoveries of chlorinated hydrocarbons, organic compounds in which one or more carbon atoms have been replaced by chlorine. By the 1970s, more than half the salt used in the United States was broken down into chlorine and sodium. Chlorine is ultimately converted into the chlorinated hydrocarbons used in plastics, such as vinyl chloride; solvents for dry cleaning; automotive fluids such as anti-freeze; and pesticides such as DDT.

Most of these uses date from about 1940. However, despite the growing chemical industry, the share of American salt used by the industry dropped to 63 percent by 1974 because of an even newer application for the product. Beginning in the 1950s, the salting of highways to remove snow and ice increased continuously until 1974 when 17 percent of all salt consumed was for this purpose. Since the automobile also accounts for the salt used in making automotive fluids and uses much of the plastics, it has clearly become the largest consumer of salt.

American salt production in 1974 was more than 46 million tons, by far the world's largest. Even so, to meet demand, 3 million tons were imported, an amount equal to the entire consumption of the country in 1900.

Bibliography

Bathe, G. "The Onondaga Salt Works of New York State." Transactions of the Newcomen Society 25 (1945–1947): 17.

Chatard, Thomas Marean. Salt-Making Processes in the United States. Washington, D.C.: U.S. Government Printing Office, 1888.

Lonn, Ella. Salt as a Factor in the Confederacy. New York: Neale, 1933; Tuscaloosa: University of Alabama Press, 1965.

McMurtrie, D. C. "Negotiations for the Illinois Salt Springs, 1802–03." Bulletin of the Chicago Historical Society. (March 1937).

Quinn, William P. The Saltworks of Historic Cape Cod: A Record of the Economic Boom in Nineteenth Century Barnstable County. Orleans, Mass.: Parnassus Imprints, 1993.

Stealy, John E. The Antebellum Kanawha Salt Business and Western Markets. Lexington: University Press of Kentucky, 1993.

 
salt, chemical compound (other than water) formed by a chemical reaction between an acid and a base (see acids and bases).

Characteristics and Classification of Salts

The most familiar salt is sodium chloride, the principal component of common table salt. Sodium chloride, NaCl, and water, H2O, are formed by neutralization of sodium hydroxide, NaOH, a base, with hydrogen chloride, HCl, an acid: HCl+NaOH→NaCl+H2O. Most salts are ionic compounds (see chemical bond); they are made up of ions rather than molecules. The chemical formula for an ionic salt is an empirical formula; it does not represent a molecule but shows the proportion of atoms of the elements that make up the salt. The formula for sodium chloride, NaCl, indicates that equal numbers of sodium and chlorine atoms combine to form the salt. In the reaction of sodium with chlorine, each sodium atom loses an electron, becoming positively charged, and each chlorine atom gains an electron, becoming negatively charged (see oxidation and reduction); there are equal numbers of positively charged sodium ions and negatively charged chloride ions in sodium chloride. The ions in a solid salt are usually arranged in a definite crystalline structure, each positive ion being associated with a fixed number of negative ions, and vice versa.

A salt that has neither hydrogen (H) nor hydroxyl (OH) in its formula, e.g., sodium chloride (NaCl), is called a normal salt. A salt that has hydrogen in its formula, e.g., sodium bicarbonate (NaHCO3), is called an acid salt. A salt that has hydroxyl in its formula, e.g., basic lead nitrate (Pb[OH]NO3), is called a basic salt. Since a salt may react with a solvent to yield different ions than were present in the salt (see hydrolysis), a solution of a normal salt may be acidic or basic; e.g., trisodium phosphate, Na3PO4, dissolves in and reacts with water to form a basic solution.

In addition to being classified as normal, acid, or basic, salts are categorized as simple salts, double salts, or complex salts. Simple salts, e.g., sodium chloride, contain only one kind of positive ion (other than the hydrogen ion in acid salts). Double salts contain two different positive ions, e.g., the mineral dolomite, or calcium magnesium carbonate, CaMg(CO3)2. Alums are a special kind of double salt. Complex salts, e.g., potassium ferricyanide, K3Fe(CN)6, contain a complex ion that does not dissociate in solution. A hydrate is a salt that includes water in its solid crystalline form; Glauber's salt and Epsom salts are hydrates.

Salts are often grouped according to the negative ion they contain, e.g., bicarbonate or carbonate, chlorate, chloride, cyanide, fulminate, nitrate, phosphate, silicate, sulfate, or sulfide.

Preparation of Salts

Salts are also prepared by methods other than neutralization. A metal can combine directly with a nonmetal to form a salt; e.g., sodium metal reacts with chlorine gas to form sodium chloride. A metal may react with a dilute acid to form a salt and release hydrogen gas; e.g., zinc reacts with dilute sulfuric acid to form zinc sulfate and hydrogen. A metal oxide may react with an acid to form a salt and water; e.g., calcium oxide reacts with carbonic acid to form calcium carbonate and water. A base can react with a nonmetallic oxide to form a salt and water; e.g., sodium hydroxide reacts with carbon dioxide to form sodium carbonate and water. Two salts may react with one another (in solution) to form two new salts; e.g., barium chloride and sodium sulfate react in solution to form barium sulfate (as an insoluble precipitate) and sodium chloride (which remains in solution). A salt may react with an acid to form a different salt and acid; e.g., sodium chloride and sulfuric acid react when heated to form sodium sulfate and release hydrogen chloride gas (which in solution forms hydrochloric acid). A salt undergoes dissociation when it dissolves in a polar solvent, e.g., water, the extent of dissociation depending both on the salt and the solvent.

Bibliography

See M. Kurlansky, Salt: A World History (2002).


 

Because salt is indispensable to life, acts as a food preservative, and uniquely flavors foods, humans have been preoccupied with it since the beginning of recorded history. The desire to obtain salt politically or militarily has influenced the histories of countries in Asia, Africa, Europe, South America, and the Middle East. Indeed, salt was used as a form of currency and had greater value than gold in some ancient societies. Even religious and magical significance has been attributed to this mineral.

In chemistry, the term "salt" generally refers to any compound that results from the interaction of an acid and a base. In the fields of geology and agriculture, the term "salt" is used as a synonym for the word "mineral." Although numerous salts are essential to human health (for example, potassium chloride, sodium hydroxide), in the following paragraphs the term "salt" will refer specifically to the inorganic, white crystalline substance that is known as sodium chloride (abbreviated NaCl), unless otherwise noted. It is also known as table salt, rock salt, sea salt, and saline. The reader should be aware that some paragraphs below refer to sodium chloride, whereas others refer to sodium, the mineral/ion/electrolyte.

When sodium chloride enters the body, it dissociates almost completely into its constituent particles, the ions sodium and chloride. Sodium chloride is soluble in water and glycerin. Sodium is the most plentiful ion in blood. As electrically charged particles, positively charged sodium (Na+) and negatively charged chloride (Cl-) are classified as electrolytes because they conduct electricity when dissolved in water.

Dietary Salt

Sodium exists in many foods that are commonly consumed in Western diets including processed sandwich meats, cheese, canned vegetables, pickled foods, salty snacks, and soft drinks. Other sources of sodium are not as well recognized: condiments, sauces, baking soda, baking powder, and bread. In restaurant foods, fast-food meals, and Chinese cuisine the sodium levels can be very high. Only about 10 percent of the sodium in Western diets is due to discretionary salt added at the table.

The sodium content of plants and vegetables depends on numerous factors. These include plant maturity, genetics, agricultural practices, soil salinity, soil fertility, soil pH, the rate at which water percolates through soil, as well as meteorological factors such as rainfall, cloud cover, and sunlight.

For most Americans today, eating preserved and processed foods has become a way of life. Sodium chloride is the most common food additive. Approximately 75 percent of sodium in Western diets originates from processed foods. Because salts of all kinds, including sodium chloride, are very stable, it is virtually impossible to remove sodium from foods that have been canned in glass or metal containers. In fact, the addition of sodium may occur during home meal preparation as well as commercial processes. For example, it is possible that a vegetable contains only 2 mg of sodium per 100 g on the vine but may contain 2 to 310 times that amount after canning. Processes such as adding a salt solution to prevent discoloration of vegetables (that is, brining), or the use of sodium salts as processing aids, also result in the addition of sodium to the final product.

Salt in Food Processing

In the late nineteenth and early twentieth centuries, before modern processing techniques existed, food preservation consisted primarily of heat sterilization used in combination with the addition of salts and spices. Salt was used to suppress the growth of unwanted bacteria. Today, sodium is added to processed foods in several forms. Sodium nitrate and sodium nitrite are added to meats as preservatives. Sodium citrate monobasic is added as a pH buffering agent. Both sodium fumarate and malic acid sodium salt are added to foods as buffering agents and flavor enhancers. These salts are used in concert with numerous other food additives in the United States (for example, antioxidants, stabilizers, colors, sweeteners, enzymes, and emulsifiers), under the direction of the U.S. Food and Drug Administration.

Fergus Clydesdale, a professor at the University of Massachusetts at Amherst, explained in 1988 that the loss of sodium during processing is solely due to leaching (that is, extraction, rinsing, or filtration). Canning, boiling, steaming, blanching, and cooking are the processes most likely to cause leaching of sodium and other salts. However, the extent to which these electrolytes are lost varies with the food product, type of processing, and properties of each ion. The amount of water used in a given commercial process also affects mineral losses. Steaming, for example, uses less water than boiling. Further, the total processing time may affect sodium losses from foods. Brief procedures will likely extract less salt than lengthy ones.

Various other salts (for example, potassium chloride, magnesium chloride, sodium nitrate, sodium benzoate, and sodium acetate) are added to foods during commercial processing. They serve to cure meats, provide or intensify the flavor of numerous products, decrease caking of dry products, stabilize pH (that is, when used with jams, gelatins, baked goods, pasteurized cheese), fortify nutrients, and enhance texture. Sodium nitrite, for example, reacts with meat pigments to develop a characteristic pink color. In bread and baked goods, salt serves a variety of functions including the control of the rate of fermentation in yeast-leavened products. Fermented vegetables such as sauerkraut require salt for flavor and to extract water and other nutrients from the plant tissue to form brine, in which desirable organisms flourish and undesirable ones are subdued. The firmness and color of fruits and vegetables are preserved by the calcium salt of lactic acid. In cheese products, salt is added to the curd or applied to the cheese surface to remove whey and to slow the production of acid. Sorbic acid and its salts are antimicrobial agents that work to suppress the growth of bacteria; molds in cheese, sausages, fruits, jellies, bread and cakes; and yeasts in salad dressings, tomato products, syrups, candies, and chocolate syrup.

Biological and Physiological Considerations

The various minerals in the human body serve to maintain acid-base balance, blood volume, and cell membrane permeability, and provide the constituents of bones and teeth. Sodium chloride is important in maintaining the proper concentration of body fluids (that is, osmolality), expediting fluid movement between cells, enhancing glucose absorption, and allowing proper conduction of impulses along nerve and muscle tissues.

Body fluids are distinguished as either intracellular (that is, existing inside muscle and organs) or extracellular (that is, circulating blood plus the interstitial fluid that lies between cells). To accomplish their functions, body tissues maintain intracellular and extracellular ions in different concentrations. This requires considerable energy, approximately one-third of all resting metabolism, and is accomplished by molecules that are embedded in cell membranes throughout the body; these large protein molecules are known as pumps because their action causes an unequal distribution of an ion on the inside and outside of a membrane. In blood, the concentrations for some ions (for example, potassium and calcium) are maintained within narrow limits. Table 1 illustrates these concepts for sodium, chloride, potassium (K+), and magnesium (Mg2+). Chloride is the most common negative ion that combines with sodium in the extracellular fluid. Sodium and chloride account for more than 80 percent of all particles in the extracellular fluid. Potassium, magnesium, and phosphate are the most abundant intracellular ions. Potassium speeds energy metabolism and is involved in the synthesis of proteins and a storage form of carbohydrate (that is, glycogen). Magnesium allows the body's chemical reactions and biochemical pathways to function efficiently. Approximately 60 percent of the body's magnesium exists in the skeleton, in combination with calcium and phosphorus; in fact, 99 percent of all calcium exists in bones and teeth. The remaining magnesium is present in red blood cells and muscle, supporting the transport and storage of oxygen.

The concentrations of ions in sweat and urine, which constitute the major avenues of loss, may vary markedly between individuals. This large range exists in sweat and urine because diet, acute exercise, chronic physical training, and heat acclimatization alter the loss of these ions—especially sodium and chloride—at the sweat glands and kidneys.

Sodium Metabolism

Sodium is so intimately related to other intracellular ions, extracellular ions, and water that it is difficult to consider the factors that regulate its metabolism independently. Nevertheless, the following text is limited to the regulation of sodium retention and excretion.

Table 1

Sodium, chloride, potassium, and magnesium ion concentrations (mmol/L) in intracellular fluid and in four extracellular fluids
SourceSodiumChloridePotassiumMagnesium
Intracellular fluid 8 150 31 10
Extracellular fluids
Sweat 15–53 4–8 2–5 15–70
Urine 32–224 43–60 8–10 39–218
Blood plasma 96–110 3–6 1–2 135–145
Saliva 11–45 11–23 0.1–0.4 10–75

At rest, the kidneys filter circulating blood at the rate of 1.0 to 1.5 L/min, causing the kidneys to generate approximately 180 L of fluid during a 24-hour period. Because the average urine volume of normal adults totals 1.3 L/day, almost all of the renal filtrate is reabsorbed and returned to the bloodstream. The amount of sodium excreted into the urine depends upon the body's need for sodium. If excess sodium is consumed without water, the kidney excretes urine with a high concentration of sodium. If dietary sodium is restricted, the kidneys are capable of producing a dilute urine that maintains the concentration of sodium in body fluids at a normal level.

Whole-body sodium balance is maintained over a wide range of dietary and environmental conditions, primarily due to the action of the hormone aldosterone on the kidneys. When dietary sodium is high, urinary sodium increases to excrete the excess. When dietary sodium is low, aldosterone reduces the loss of sodium in urine appropriately. Thus, a sodium deficiency is rare, even among individuals who consume very low-sodium diets (see below). The body may experience a sodium deficiency when sweat losses are large and persistent, or when illness (for example, chronic diarrhea, renal disease) results in inadequate sodium retention by the kidneys. Following major changes in dietary sodium levels, concentrations of the following hormones also adapt, suggesting that they minimize perturbations of extracellular fluid-ion balance: renin, angiotensin II, atrial natriuretic peptide, and nitric oxide. The latter compound plays a pivotal role in blood pressure maintenance by regulating sodium and water excretion at the kidneys. Despite our knowledge of these facts, scientists cannot explain the exact mechanism by which the brain assesses whole-body sodium status.

A predictable sequence of events occurs when a normal individual limits the intake of sodium (for example, 230 mg daily). During the initial days of salt restriction, urinary sodium levels progressively decrease until about the fifth day, when the 24-hour losses become small (for example, 115 mg or less). This individual ordinarily loses 1 or 2 kg of body weight, which is attributable to the loss of sodium and an appropriate volume of water. Initially, the reduced body water comes almost exclusively from the extracellular fluid; as time passes, the intracellular fluid compartment also shrinks. For the next few days, urinary sodium concentration remains low, and the body continues to maximize salt conservation until a reduced whole-body sodium equilibrium is established. Sweat sodium levels decrease in a manner similar to urine during dietary restriction; both are due to the action of the hormone aldosterone.

Toxicity

As is true for virtually all nutrients and compounds, salt can be detrimental or lethal in large quantities. Direct contact with sodium chloride can cause skin irritation, and heating it to high temperatures emits a vapor that irritates the eyes. When heated to the point of decomposition, it emits toxic chloride and disodium oxide (Na2O) fumes. When consumed in large amounts, sodium chloride can cause stomach irritation. In addition, laboratory experiments have shown the following dose-response effects: 50 mg/24 hr, skin irritation in rabbits; 100 mg/24 hr, moderate eye irritation in rabbits; 125 ml/L, inhibition of DNA synthesis in isolated human cells; 27 mg/kg body weight, abortion of a human fetus; and 3,000 mg/kg body weight, lethal oral dose for 50 percent of the animals tested. Potassium chloride causes physiological responses at the following doses: 500 mg/24 hr, mild eye irritation in rabbits; 125 g/L, lung cell death in hamsters; 2,600 mg/kg body weight, lethal oral dose for 50 percent of the animals tested. Calcium chloride is lethal for 50 percent of the animals tested at a dose of 1,000 mg/kg body weight, when administered orally, and at an intraperitoneal dose of 264 mg/kg body weight. Studies have shown that magnesium chloride is lethal for 50 percent of rats tested at an oral dose of 2,800 mg/kg body weight.

The preservatives known as sulfites (see Sodium and Hypertension, below) can produce deleterious side effects, when consumed in large quantities. Investigations involving laboratory animals have shown that sulfites may inhibit some of the body's biochemical reactions and retard whole-body growth in infants; cause gastrointestinal distress; and induce reversible anemia, nutrient deficiency (for example, thiamine), and gene mutations. A lethal oral dose of sodium bisulfite (50 percent of the animals tested) was 498 mg/kg body weight in rats and 300 mg/kg body weight in mice.

Monosodium glutamate (MSG) is added to foods by chefs to potentiate various flavors. This effect is greatest in meat-and vegetable-based soups, sauces, gravies, and spice blends. The levels of MSG in foods range from approximately 0.3 percent in spinach and tomatoes to about 10 percent in parmesan cheese and 20 percent in dehydrated soup mixes. Some consumers also mix additional MSG into foods in the form of sauces. This may be strongly influenced by cultural food preferences. In Korea and Taiwan, for example, the average adult consumes six to ten times more MSG each day than the average person in the United States. Because sodium is a part of the molecular structure of MSG, it becomes available as free, metabolically active sodium. Therefore, individuals who consume restricted-sodium diets (see Sodium and Hypertension, below) should monitor both the natural levels of MSG in foods as well as the amount that is intentionally added. Monosodium glutamate also produces unwanted side effects in some individuals, including warmth, tingling, tightness, headache, swelling of the liver, and a feeling of pressure in the upper body or face. This phenomenon is often associated with consumption of Chinese food because of its high MSG content. The toxicity of MSG has been studied extensively and it is relatively low, compared to other salts. It has been estimated, for example, that an average adult, weighing 70 kilograms, would have to consume more than 3 pounds of MSG at one time to experience a toxic effect. This does not mean, however, that detrimental effects are nonexistent. A large quantity of MSG has been associated with convulsions, vomiting, and nerve cell damage in research animals, although there are great differences between species. Studies have shown that MSG is lethal, for 50 percent of rats tested, when consumed as an oral dose of 17,300 mg/kg body weight. Thus, when consumed in typical amounts, MSG does not appear to induce illness or toxicity. Because the scope of this article does not allow detailed considerations of the toxicities of other salts, the reader may refer to the book Food Additive Toxicology for further information.

Sodium and Hypertension

Because the kidneys regulate the volume of circulating blood, they are intimately involved in the genesis of high blood pressure (that is, hypertension). This disease often involves excessive retention of extracellular fluid, especially in the bloodstream. For unknown reasons, resistance to blood flow through the kidneys is increased two-to fourfold. And, unfortunately, even though blood pressure may be reduced by prescription medications, the kidneys do not excrete normal amounts of salt and water in urine. This scant urine output causes water and sodium retention until blood pressure rises again to an elevated level. Treatment for this fluid and electrolyte retention often involves diuretics, which increase hourly water and salt losses in urine markedly. Considering these facts, a multiple-stage scientific hypothesis has evolved. This concept proposes that a high dietary sodium intake (1) overloads the kidneys' capacity to excrete sodium and results in fluid retention, (2) increases endocrine gland secretion (that is, natriuretic hormone), (3) inhibits cell membrane function, (4) increases the sodium concentration inside cells and calcium levels in the smooth muscles that encircle blood vessels, which (5) subsequently increases the resistance to blood flow and blood pressure. Interestingly, some research indicates that hypertension may be dependent on the coexistence of sodium and chloride in the diet. Consumption of chloride salts (for example, potassium chloride and calcium chloride) is associated with hypertension, in a way similar to that of sodium.

Forty-three million Americans live with persistently high blood pressure, defined as readings of 140/90 mm Hg or above; this represents 24 percent of the adult population of the United States. This makes it one of today's most prevalent disease conditions. High blood pressure increases the risk of stroke, heart disease, and kidney failure. Individuals with a family history of hypertension, the elderly, middle-aged men, and middle-aged black women are at greatest risk. Yet, everyone is vulnerable because blood pressure typically rises with age.

It is important to acknowledge that heredity plays a critical role in hypertension and that this complex disease is affected by many different genes. Present wisdom states that, without these genes, a person will not develop high blood pressure. Such individuals, whose blood pressure increases with increasing sodium consumption, are salt-sensitive. This explains why there are great differences in human responses to sodium chloride.

Several factors play a role in reducing high blood pressure. In hypertensive adults, for example, a single aerobic exercise session (45 minutes) reduces blood pressure for 12 to 24 hours. A healthy diet (high in fruits, vegetables, low-fat dairy products; low in saturated and total fat) also reduces blood pressure. But salt has received the most attention. There is a large body of evidence, and consensus within the scientific community, that dietary sodium chloride is a risk factor for high blood pressure, independent of other risk factors such as alcohol and obesity. During the last 25 years, numerous professional organizations and advocacy groups have supported reductions of sodium in commercially processed foods, including the American Academy of Pediatrics, American College of Cardiology, Food Research Action Center, American College of Preventive Medicine, American Health Foundation, National Alliance of Senior Citizens, and National Urban Coalition.

In countries where dietary sodium is low, high blood pressure is rare. According to clinical investigations, when hypertensive adults reduce salt consumption their blood pressure usually decreases, although not always to a normal level. Additional evidence suggests that a high-salt diet aggravates other illnesses including asthma, gastric cancer, kidney stones, and osteoporosis. Therefore, consuming a low-salt diet will, for many people, reduce their risk of developing or aggravating a chronic illness such as cardiovascular stroke.

Individuals who are placed on sodium-restricted diets often consume other salts in place of sodium chloride. This increases the daily potassium intake because salt substitutes usually contain a high percentage of potassium chloride. This dietary strategy offers potential health benefits in the form of lowered blood pressure and reduced risk of stroke. For some individuals, however, the use of a potassium-containing salt substitute can cause illness or death. Individuals with a disease, those taking medications, and the elderly should be advised that these salt substitutes ought to be used only to enhance taste, and not for cooking purposes. Sulfites also should be considered. These compounds preserve food by retarding deterioration, rancidity, or discoloration and thus are categorized as antioxidants. At least three sulfites are commonly used as food additives: sodium sulfite (Na2SO3), sodium metabisulfite (Na2S2O5), and sodium bisulfite (NaHSO3). Because these preservatives contain sodium that becomes free and metabolically active in cells, each contributes to the diet's total sodium load.

Unfortunately, reducing the salt content of foods, to restrict sodium consumption, affects the quality and properties of foods. In the meatpacking industry, for example, reducing sodium chloride extremely results in inferior meat cohesion and water retention, and reduces shelf life. These and other unwanted effects explain why commercial food processors usually do not reduce the sodium chloride levels in their products voluntarily.

Managing Dietary Sodium

Compared to the average daily intake in the United States, ranging from 2,300 to 6,900 mg/day, the minimum physiological need for sodium (40 to 300 mg/day) and the intake necessary for good health (500 mg/day) are very small. In fact, the amount of sodium in fresh vegetables alone may be enough to meet an adult's basal requirement. Eight simple procedures make reducing salt intake effective. First, cook with only small amounts of added salt. Second, add little or no salt to food at the dinner table. Third, limit your intake of salty foods such as potato chips, salted nuts, pretzels, popcorn, soy sauce, steak sauce, garlic sauce, pickled foods, and cured meats. Fourth, request that the chef omit salt from your restaurant meal. Fifth, educate yourself about foods that contain large qualities of sodium and seek low-sodium brands when shopping for crackers, pasta sauce, canned vegetables, bread, and other commercial products. Sixth, develop a taste for the unsalted flavor of foods. The taste preference for salty foods can be altered with patience. Seventh, evaluate your diet by reading food labels carefully to determine the sodium content. This can be especially helpful in the aisles of a supermarket because you cannot eat what you do not purchase. Eighth, make a mental list of foods that you will avoid because they contain too much sodium. Here are a few examples, presented in units of milligrams per 100 g of food: fried crisp bacon, 2,400; baking soda, 9,000; beef bouillon cube, 24,000; bologna, 1,300; celery salt, 28,000; cured ham, 1,100; dill pickle, 1,400; frankfurters, 1,100; salt pork, 1,800; green pickled olives, 2,400; and processed cheese, 1,500.

Careful selection of low-sodium food items also will prove to be useful. Table 2 provides a comparison of the sodium content of several vegetables, in fresh and canned forms. Obviously, individuals who desire to reduce their total dietary sodium levels should substitute fresh vegetables for canned varieties, whenever possible. The exception to this recommendation lies in vegetables that lose sodium during processing, due to leaching. This provides the added benefit of ensuring that other dietary nutrients are not lost during commercial packaging (that is, leaching, boiling, blanching).

Another excellent way to lower sodium intake is to alter food preparation practices in the home. Many spices, herbs, and other flavorings do not contribute significant amounts of sodium but may be used to improve the flavor of low-sodium meals. These include allspice, basil, bay leaf, chives, cinnamon, cloves, curry, dill, garlic, ginger, leeks, lemon juice, mint, mustard, nutmeg, orange extract, oregano, paprika, parsley, pepper, peppermint, pimento, poppy seed, saccharin, saffron, sage, sesame, brown and white sugar, tarragon, vanilla extract, and wine.

In determining the amount of sodium that a person consumes, groundwater is often ignored. However, the sodium content of public and private aquifers in the United States varies greatly from one location to another. Although most sources of water include less than 20 mg of sodium per liter, a minor input to daily sodium, certain areas of Arizona, Texas, and Illinois report 325 to 432 mg of sodium per liter of groundwater. Considering the fact that the average adult consumes more than 2 L of fluid each day, this could mean that some Americans receive over 1 g of sodium per day from tap water alone. If a water softener is used to reduce hardness from a local water supply (for example, remove the mineral calcium carbonate), sodium content can be magnified.

Table 2

Sodium content (milligrams per cup) of vegetables: Fresh versus canned
  Fresh, rawCanned
Asparagus 4 285
Beets 57 36
Carrots 31 280
Green beans 8 536
Green peas 2 236
Lima beans 1 310
Sweet potatoes 24 48
Tomatoes 2 18
Tomato juice 2 230

Individuals on low-salt diets also should be concerned about the adequacy of other nutrients. It has been estimated that 40 percent of all low-sodium diets lack other essential nutrients, especially protein, the B vitamins, riboflavin, and calcium. These deficiencies result from the removal of food items that contain sodium.

Salt Restriction and Sodium Deficiencies

As noted above, the basal physiologic need for sodium is 40 to 300 mg/day and the amount recommended for good health is 500 mg/day. Field studies, conducted between 1931 and 1962, confirmed that adults can eat low-sodium diets and remain healthy. Interestingly, some of these populations lived in tropical climates, where sweat losses were great, including the vigorous Masai warriors of Africa who consume less than 1,955 mg of sodium per day, the inhabitants of tropical Nigeria who ingest less than 2,760 mg of sodium per 24-hour period, and Galilean naturalists who ingest only 736 mg of sodium per day.

It is difficult to deplete the body of sodium. The action of the hormone aldosterone on the kidneys, and the relatively large per capita daily intake of sodium in Western diets relative to basal physiological needs, are quite adequate to maintain whole-body sodium levels. Thus, sodium deficiencies are rare, but may be experienced in three extraordinary situations. The first involves dietary salt restriction as therapy for disease (for example, hypertension or congestive heart failure). The possibility that sodium depletion may occur in these illnesses does not contraindicate the use of a low-sodium diet when suitable, but it is important that the patient be monitored carefully. Frequent measures of serum sodium concentration are desirable during the first few weeks of a salt-restricted diet. A decline in serum sodium level should prompt a reevaluation. The second circumstance involves diseases of the kidneys or endocrine glands that alter normal sodium balance, such as Addison's disease or diabetes insipidus. The third situation, involving hot environments, is considered in the following section.

Hot Environments Exaggerate Salt Losses

Exercise or labor in cool environments increases the sweat loss and water intake, but the psychological drive to drink and fluid-electrolyte hormones regulate total body water within >0.2 percent (>150 g) of the normal body weight each day. Blood plasma volume is regulated within > 0.7 percent (> 25 g) on consecutive days.

During mild-to-moderate intensity exercise in a hot environment, voluntary water intake does not keep pace with water losses. Most humans produce 0.8 to 1.3 L of sweat per hour, but replace only one-third to three-fourths of this amount by drinking. Thus, if exercise in a hot environment is prolonged and strenuous, a 3 to 5 percent body weight loss can occur. This is significant because, at these levels, both endurance and strength decline.

Table 1 demonstrates that sweat contains sodium, chloride, and other minerals. In fact, sweat contains more than forty distinct organic compounds. Regarding the sodium chloride content, considerable interindividual differences exist among healthy adults. Physically fit athletes who are heat-acclimatized (that is, adapted to exercise in a hot environment) usually lose 400 to 800 mg of sodium chloride per liter of sweat. In contrast, the sweat of unfit, nonacclimatized adults contains from 1,000 to 3,000 mg of sodium chloride per liter. This difference occurs because physical training and heat acclimatization reduce the concentration of salt in sweat.

Salt Balance During Exercise and Labor

Table 3 provides estimates of the amount of fluid and salt lost in sweat, during different activities that are conducted in hot environments. Obviously, water and sodium chloride losses increase in proportion to the duration and the intensity of exercise. As a point of reference, Table 4 describes selected nutrients that are consumed by an adult in the United States. The intake of sodium chloride averages 4,600 to 12,700 mg, and water consumption averages 2.5 L/day. Comparing these two tables, it becomes obvious that 30 minutes of mild gardening produces a small fluid and sodium loss that can be replaced by a normal diet. An ultramarathon, requiring 20 to 30 hours to complete, involves extraordinary salt (14,400 to 70,000 mg NaCl) and water (18.0 to 35.0 L) losses that far exceed normal 24-hour food consumption. Clearly, constant fluid-electrolyte intake is required, during and after an ultramarathon, to replace lost nutrients.

Three fluid-electrolyte disorders involve sodium (that is, heat exhaustion, heat cramps, and exercise-related hyponatremia) and have become the most common illnesses among athletes and laborers in hot environments. Heat exhaustion, an inability to continue exercise in the heat, is primarily a fluid depletion disorder in which either large sodium, water, or mixed sodium-water losses occur during exercise-heat exposure. Heat cramps occur most often in the abdominal wall and large muscles of the extremities and are due to whole-body sodium depletion. Treatment for these two heat illnesses involves replacing the sodium chloride and water that was lost in sweat and urine. Exertional hyponatremia involves a reduced serum sodium concentration (<130 mEq/L) and represents a marked dilution of the extracellular fluid. This disorder, unlike the previous two, involves overhydration. Athletes or laborers, who consume and retain a large volume of pure water (for example, 10 L in 5 hr), may experience a life-threatening series of physiological changes that signal water intoxication. The most serious effects are coma, fluid in the lungs (pulmonary edema), and brain swelling (cerebral edema).

Table 3

The amount of water and sodium chloride lost in sweat during labor or during exercise in hot environments
Event, Duration, Personal CharacteristicsTotal Water Loss (L)Sodium Loss (mg)a
Mild gardening, 30 min, sedentary adult 0.3–0.5 240–2,000
Strenuous work, 60 min, experienced laborer 0.8–1.5 640–4,500
10-km run, 40 min, healthy adult 0.5–1.0 400–4,000
Leisure hike, 2 hr with rest, heat-acclimatized adult 2.0 1,600–6,000
Intense cycling, 2–4 hr, physically-fit cyclist 3.0–8.0 2,400–24,000
Ultramarathon, 20–30 hr, highly trained runnerb 18.0–35.0 14,400–70,000
aLoss in sweat and urine; these calculations assume a range of 800–4,000 mg sodium chloride per liter of sweat; physical training and heat acclimatization increase a person's sweat rate but decrease the sodium content of sweat and urine.
bRunning pace is slow and includes walking.
SOURCE: Average Consumption of Selected Minerals and Sodium Chloride in the United States (mg/day). National Research Council, 1989.

Table 4

Consumption of selected nutrients in the United States (mg per day), as published by the National Research Council in 1989.
MineralAmount consumed (mg/day)a
Sodium chloride 4,600–12,700
Sodium 1,800–5,000
Potassium 2,500–3,400
Magnesium 207–329
Calcium 530–1,179
aThe water intake of a 70-kg adult is approximately 2.5 L/day, in solid foods and fluid.

Replacing Salt Losses Due to Exercise

Individuals who exercise for more than two hours, and who are not hypertensive, should increase their salt intake slightly (see Table 3). Similarly, if a weight loss of 3 percent or more is due to fluid losses during work or exercise, a minor sodium deficit should be expected. The simplest means to replace these deficits after exercise involve adding salt to your meals and selecting saltier foods. Canned soup, for example, contains 1,950 to 2,450 mg of sodium chloride; canned tomato juice contains 1,525 mg. Fluid-electrolyte replacement beverages contain 150 to 300 mg, and 1 percent low-fat milk contains 300 mg sodium chloride It also is wise to eat more fruits, such as bananas and watermelon, to replace lost potassium.

Two Low-Sodium Recipes

The April 1985 issue of FDA Consumer magazine provided two recipes as examples of low-sodium meal items that are easy to prepare. The first describes baked dinner rolls and yields 100 servings: 3¼ounces active dry yeast, 2 quarts water, 7¼ pounds all-purpose flour, 1⅓ cups sugar, 1 tablespoon salt. Normally, a recipe of this size would utilize 4 tablespoons of salt, resulting in a sodium content of 295 mg in each roll. By reducing the amount of salt by 25 percent, each roll contains only 73 mg of sodium.

The second recipe describes low-sodium sausage patties and yields 16 servings. Mix 1 pound ground beef with 1 tablespoon lemon juice, ¼ cup dry bread crumbs, ¼ teaspoon sage, 1⁄4 teaspoon ginger, 1 teaspoon garlic powder, 1 teaspoon onion power, and ½ teaspoon liquid smoke. Dissolve 1 low-sodium bouillon cube in water and add this solution to the ground beef mixture. Mix thoroughly and let stand for 15 minutes. Form sixteen 1-ounce patties. Brush skillet with vegetable oil and cook the patties for seven to eight minutes on each side, or modify the time as desired. The use of low-sodium bouillon is the key to sodium reduction in this recipe.

Bibliography

Appel, Lawrence J., Thomas J. Moore, Eva Obarzanek, William M. Vollmer, Laura P. Svetkey, Frank M. Sacks, George A. Bray, Thomas M. Vogt, Jeffrey A. Cutler, Marlene M. Windhauser, Lin Pao-Hwa, and Njeri Karanja. "A Clinical Trial of the Effects of Dietary Patterns on Blood Pressure." New England Journal of Medicine 336 (1997): 1117–1124.

Buskirk, Elsworth, and William B. Farquhar. "Sodium in Exercise and Sport." In Macroelements, Water, and Electrolytes, edited by Judy A. Driskell and Ira Wolinsky, pp. 109–136. Boca Raton, Fla.: CRC Press, 1999.

Clydesdale, Fergus M. "Minerals: Their Chemistry and Fate in Food." In Trace Minerals in Foods, edited by Kenneth T. Smith, pp. 57–94. New York: Marcel Dekker, 1988.

Dahl, L. K. "Salt and Hypertension." American Journal of Clinical Nutrition 25 (1972): 234–244.

Denton, Derek. "Salt in History: Symbolic, Social, and Physiological Aspects." In The Hunger for Salt, pp. 76–90. Berlin: Springer-Verlag, 1982.

Freeman, Thomas M., and Owen W. Gregg. Sodium Intake—Dietary Concerns. St. Paul, Minn.: American Association of Cereal Chemists, 1982.

Greeley, Alexandra. A Pinch of Controversy Shakes Up Dietary Salt. Health and Human Services Publication HE20.4010/ A:SA3/3. Rockville, Md.: Food and Drug Administration, 1997.

Hubbard, Roger W., and Lawrence E. Armstrong. "The Heat Illnesses: Biochemical, Ultrastructural, and Fluid-Electrolyte Considerations." In Human Performance Physiology and Environmental Medicine at Terrestrial Extremes, edited by Kent B. Pandolf, Michael N. Sawka, and Richard R. Gonzalez, pp. 305–360. Indianapolis: Benchmark Press, 1988.

Maga, Joseph A., and Anthony T. Tu. Food Additive Toxicology. New York: M. Dekker, 1995.

Miller, Roger W. Low-Sodium Menus Pass School Tests. Health and Human Services Publication 85-2204. Rockville, Md.: Food and Drug Administration, 1985.

National Research Council. Food and Nutrition Board. Sodium-Restricted Diets. The Rationale, Complications, and Practical Aspects of Their Use. Publication No. 325. Washington, D.C.: National Research Council, 1954.

National Research Council. Recommended Dietary Allowances, 10th ed. Washington, D.C.: National Academy Press, 1989.

Sofos, John N., and S. Raharjo. "Salts." In Food Additive Toxicology, edited by Joseph A. Maga and Anthony T. Tu, pp. 235–268. New York: M. Dekker, 1995.

Taylor, Reginald J. Food Additives. Chichester, England: John Wiley & Sons, 1980.

Taylor-Tolbert, Nadine S., Donald R. Dengel, Michael D. Brown, Steve D. Cole, Richard E. Pratley, Robert E. Ferrell, and James M. Hagberg. "Ambulatory Blood Pressure After Acute Exercise in Older Men with Essential Hypertension." American Journal of Hypertension 13 (2000): 44–51.

United Nations Food and Agriculture Organization. Specifications for Identity and Purity of Certain Food Additives. Rome: United Nations, 1986.

United States House of Representatives. Sodium in Food and High Blood Pressure. Committee on Science and Technology Document No. 84-015O. Washington, D.C.: U.S. Government Printing Office, 1981.

—Lawrence E. Armstrong

 

In chemistry, a compound resulting from the combination of an acid and a base, which neutralize each other.

  • Common table salt is sodium chloride.
  •  

    (of cattle) a term used in the US where placement site of salt on a range area is moved so as to attract cattle to the new placement area; also used to move cattle from mountain grazing.

     
    Nutritional Values: The Nutritional Value for: salt
    Top

    Quantity Energy
    (calories)
    Carbohydrates
    (grams)
    Protein
    (grams)
    Cholesterol
    (milligrams)
    Weight
    (grams)
    Fat
    (grams)
    Saturated Fat
    (grams)
    1 tsp 0 0 0 0 5.5 0 0
     
    Essay: Salt and the fall of civilization
    Top

    A common theory about the rise of civilization is that the need for state organization of irrigation became the prime mover that led to all other changes. Irrigation may also be implicated in the fall of civilizations. Mesopotamia provides the main example. When large-scale irrigation began in the Tigris and Euphrates river valleys, it was accompanied by urban growth, writing, empires, monumental construction, and such technological innovations as the wheel. The former desert prospered and was central to the growth of human population and influence for about 4000 years. The former desert land became known as the Fertile Crescent. Today the Fertile Crescent is mostly desert again.

    Although there are several factors involved in the decline back into desert, salt in the soil appears to be the major one. The process of irrigation reverses the normal flow of water through the soil. Outside the desert, soil is watered mainly by rain that carries salt in the soil deeper into the ground. Evaporation in an irrigated desert causes water in the soil to move from lower levels toward the top of the soil as the Sun dries out upper layers. Such movement carries salt toward the surface.

    Most plants cannot grow in salty soil. Romans, appreciating this, sowed salt on the ruins of Carthage after its defeat to prevent it from returning to power.

    Flooding can erase the effects of irrigation by washing the salt back into lower regions of the soil. Egypt and China, subject to floods, have had fewer problems with salty soil than has Mesopotamia. In Egypt, however, damming of the Nile in 1964 prevented flooding but also started a buildup of salt in the soil.

    The Maya practiced irrigation in a rain forest, where salt buildup would seem less likely than in a desert. Nevertheless, it appears that they too managed with irrigation to reverse the normal flow of minerals through the porous limestone soil of Central America, contributing to the collapse of their civilization as well.

    Today farmers in other irrigated regions, such as Pakistan and the San Joaquin Valley in the United States, face similar buildup of salt in the soil.

     
    Word Tutor: salt
    Top
    pronunciation

    IN BRIEF: White crystalline form of especially sodium chloride used to season and preserve food.

    pronunciation The best smell is bread; the best savor, salt; the best love, that of children. — George Herbert (1593-1633), English clergyman, writer and metaphysical poet.

     
    Dream Symbol: Salt
    Top

    Used as seasoning in food, salt symbolizes flavor or piquancy. As one of the three primary elements of matter in alchemy, representing-in contrast to mercury and sulfur-the principle of fixity and solidity, salt symbolizes someone who is steadfast and dependable, "the salt of the earth."


     
    Wikipedia: Salt
    Top
    Salt is mostly sodium chloride (NaCl). This salt shaker also contains grains of rice, which some use to prevent caking.
    Brine being boiled down to pure salt in Zigong, People's Republic of China

    Salt is a dietary mineral composed primarily of sodium chloride that is essential for animal life, but toxic to most land plants. Salt flavor is one of the basic tastes, an important preservative and a popular food seasoning.

    Salt for human consumption is produced in different forms: unrefined salt (such as sea salt), refined salt (table salt), and iodized salt. It is a crystalline solid, white, pale pink or light gray in color, normally obtained from sea water or rock deposits. Edible rock salts may be slightly grayish in color because of this mineral content.

    Chloride and sodium ions, the two major components of salt, are necessary for the survival of all known living creatures, including humans. Salt is involved in regulating the water content (fluid balance) of the body. Salt cravings may be caused by trace mineral deficiencies as well as by a deficiency of sodium chloride itself. Conversely, overconsumption of salt increases the risk of health problems, including high blood pressure.

    Contents

    History

    Human beings have used canning and artificial refrigeration for the preservation of food for approximately the last two hundred years, however, in the millennia before then, salt provided the best-known food preservative, especially for meat.[1] The harvest of salt from the surface of Xiechi Lake near Yuncheng in Shanxi, China dates back to at least 6000 BC, making it one of the oldest verifiable saltworks.[2]:18–19

    Salt was included among funereal offerings found in ancient Egyptian tombs from the third millennium BC, as were salted birds and salt fish.[2]:38 From about 2800 BC, the Egyptians began exporting salt fish to the Phoenicians in return for Lebanon Cedar, glass, and the dye Tyrian purple; the Phoenicians traded Egyptian salt fish and salt from North Africa throughout their Mediterranean trade empire.[2]:44

    Along the Sahara, the Tuareg maintain routes especially for the transport of salt by Azalai (salt caravans). In 1960, the caravans still transported some 15, 000 tons of salt, but this trade has now declined to roughly a third of this figure.[3]

    Salzburg, Hallstatt, and Hallein lie on the river Salzach in central Austria, within a radius of no more than 17 kilometres. Salzach literally means "salt water" and Salzburg "salt city", both taking their names from the Germanic root for salt, salz. Hallstatt literally means "salt town" and Hallein "saltwork", taking their names from hal(l)-, a root for salt found in Celtic, Greek, and Egyptian.[citation needed] The root hal(l)- also gave us Gaul, the Roman exonym for the Celts, Halle and Schwäbisch Hall in Germany, Halych in Ukraine, and Galicia in Spain: this list of places named for Celtic saltworks is far from complete.[4][5][6]

    Hallstatt gave its name to the Celtic archaeological culture that began mining for salt in the area in around 800 BC Around 400 BC, the Hallstatt Celts, who had heretofore mined for salt, began open pan salt making. During the first millennium BC, Celtic communities grew rich trading salt and salted meat to Ancient Greece and Ancient Rome in exchange for wine and other luxuries.[1]

    It is widely, though incorrectly[7], believed that troops in the Roman army were paid in salt. Even widely-respected historical works repeat this error.[2]:63 The word salad literally means "salted," and comes from the ancient Roman practice of salting leaf vegetables.[2]:64

    Mahatma Gandhi led at least 100, 000 people on the "Dandi March" or "Salt Satyagraha", in which protesters made their own salt from the sea, which was illegal under British rule, as it avoided paying the "salt tax". This civil disobedience inspired millions of common people, and elevated the Indian independence movement from an elitist struggle to a national struggle.

    In religion

    According to Strong's Concordance, there are forty-one verses which reference salt in the English translation of the King James Bible, the earliest being the story of Lot's wife, who was turned into a pillar of salt when she disobediently looked back at the wicked cities of Sodom (Genesis 19:26). When King Abimelech destroyed the city of Shechem he is said to have "sowed salt on it;" a phrase expressing the completeness of its ruin. (Judges 9:45.) In the Sermon on the Mount, Jesus referred to his followers as the "salt of the earth". The apostle Paul also encouraged Christians to "let your conversation be always full of grace, seasoned with salt" (Colossians 4:6).

    In one of the Hadith recorded in Sunan Ibn Majah, Prophet Muhammad is reported to have said that: "Salt is the master of your food. God sent down four blessings from the sky - fire, water, iron and salt"

    Salt is mandatory in the rite of the Tridentine Mass.[8] Salt is used in the third item (which includes an Exorcism) of the Celtic Consecration (cf. Gallican rite) that is employed in the consecration of a church. Salt may be added to the water "where it is customary" in the Roman Catholic rite of Holy water.

    Salt is considered to be a very auspicious substance in Hindu mythology, and is used in particular religious ceremonies like housewarmings and weddings.

    In many Pagan religions esp. Wicca salt is symbolic of the element Earth. It is also used as a purifier of sacred space.

    In the native Japanese religion Shinto, salt is used for ritual purification of locations and people, such as in Sumo Wrestling.

    In Aztec mythology, Huixtocihuatl was a fertility goddess who presided over salt and salt water.

    In order to preserve the covenant between their people and God, Jews dip the Sabbath bread in salt.[9]

    The Ancient Egyptians, Greeks and Romans invoked their gods with offerings of salt and water. This is thought to be the origin of the Holy Water used in the Christian faith.[10]

    Forms of salt

    Unrefined salt

    A commercial pack of sea salt

    Different natural salts have different mineralities, giving each one a unique flavor. Fleur de sel, natural sea salt harvested by hand, has a unique flavor varying from region to region.

    Some advocates for sea salt assert that unrefined sea salt is healthier than refined salts.[11] However, completely raw sea salt is bitter because of magnesium and calcium compounds, and thus is rarely eaten. The refined salt industry cites scientific studies saying that raw sea and rock salts do not contain enough iodine salts to prevent iodine deficiency diseases.[12]

    Unrefined sea salts are also commonly used as ingredients in bathing additives and cosmetic products. One example are bath salts, which uses sea salt as its main ingredient and combined with other ingredients used for its healing and therapeutic effects.

    Refined salt

    Salt mounds in Bolivia.

    Refined salt, which is most widely used presently, is mainly sodium chloride. Food grade salt accounts for only a small part of salt production in industrialised countries (3% in Europe[13]) although worldwide, food uses account for 17.5% of salt production[14]. The majority is sold for industrial use. Salt has great commercial value because it is a necessary ingredient in the manufacturing of many things. A few common examples include: the production of pulp and paper, setting dyes in textiles and fabrics, and the making of soaps and detergents.

    The manufacture and use of salt is one of the oldest chemical industries.[15] Salt is also obtained by evaporation of sea water, usually in shallow basins warmed by sunlight;[16] salt so obtained was formerly called bay salt, and is now often called sea salt or solar salt. Today, most refined salt is prepared from rock salt: mineral deposits high in salt.[citation needed] These rock salt deposits were formed by the evaporation of ancient salt lakes,[17] and may be mined conventionally or through the injection of water. Injected water dissolves the salt, and the brine solution can be pumped to the surface where the salt is collected.

    After the raw salt is obtained, it is refined to purify it and improve its storage and handling characteristics. Purification usually involves recrystallization. In recrystallization, a brine solution is treated with chemicals that precipitate most impurities (largely magnesium and calcium salts).[18] Multiple stages of evaporation are then used to collect pure sodium chloride crystals, which are kiln-dried.

    Single-serving salt packets.

    Since the 1950s it has been common to add a trace of sodium ferrocyanide to the brine in the United Kingdom; this acts as an anticaking agent by promoting irregular crystals.[19] Sodium ferrocyanide has been banned in the United States and a similar ban has been discussed in the United Kingdom, but was determined to be unnecessary.[20], [21] Other anticaking agents (and potassium iodide, for iodised salt) are generally added after crystallization.[citation needed] These agents are hygroscopic chemicals which absorb humidity, keeping the salt crystals from sticking together. Some anti-caking agents used are tricalcium phosphate, calcium or magnesium carbonates, fatty acid salts (acid salts), magnesium oxide, silicon dioxide, calcium silicate, sodium aluminosilicate, and calcium aluminosilicate. Concerns have been raised regarding the possible toxic effects of aluminium in the latter two compounds[citation needed]; however, both the European Union and the United States Food and Drug Administration (FDA) permit their use.[22] The refined salt is then ready for packing and distribution.

    Table salt

    Table salt is refined salt, 99% sodium chloride.[23][24] It usually contains substances that make it free-flowing (anti-caking agents) such as sodium silicoaluminate or magnesium carbonate. It is common practice to put a desiccant, such as a few grains of uncooked rice[25], in salt shakers to absorb extra moisture and help break up clumps when anti-caking agents are not enough. Table salt has a particle density of 2.165 g/cm3, and a bulk density (dry, ASTM D 632 gradation) of about 1.154 g/cm3.[26]

    Salty condiments

    In many East Asian cultures, salt is not traditionally used as a condiment.[27] However, condiments such as soy sauce, fish sauce and oyster sauce tend to have a high salt content and fill much the same role as a salt-providing table condiment that table salt serves in western cultures.

    Additives

    Iodized salt (BrE: iodised salt) is table salt mixed with a minute amount of potassium iodide, sodium iodide, or sodium iodate. Iodized salt is used to help reduce the incidence of iodine deficiency in humans. Iodine deficiency commonly leads to thyroid gland problems, specifically endemic goiter, a disease characterized by a swelling of the thyroid gland, usually resulting in a bulbous protrusion on the neck. While only tiny quantities of iodine are required in the diet to prevent goiter, the United States Food and Drug Administration recommends (21 CFR 101.9 (c)(8)(iv)) 150 micrograms of iodine per day for both men and women. Iodized table salt has significantly reduced disorders of iodine deficiency in countries where it is used.[28] Iodine is important to prevent the insufficient production of thyroid hormones (hypothyroidism), which can cause goitre, cretinism in children, and myxedema in adults.

    Table salt is mainly employed in cooking and as a table condiment. The amount of iodine and the specific iodine compound added to salt varies from country to country. In the United States, iodized salt contains 46-77 ppm, while in the UK the iodine content of iodized salt is recommended to be 10-22 ppm.[29] Today, iodized salt is more common in the United States, Australia and New Zealand than in the United Kingdom.

    In some European countries where drinking water fluoridation is not practiced, fluorinated table salt is available. In France, 35% of sold table salt contains either sodium fluoride or potassium fluoride.[30] Another additive, especially important for pregnant women, is Folic acid (Vitamin B9), which gives the table salt a yellow color.

    In Canada, at least one brand (Windsor salt) contains invert sugar. The reason for this is unclear.

    Health effects

    SEM image of a grain of table salt.

    Sodium is one of the primary electrolytes in the body. All four cationic electrolytes (sodium, potassium, magnesium, and calcium) are available in unrefined salt, as are other vital minerals needed for optimal bodily function. Too much or too little salt in the diet can lead to muscle cramps, dizziness, or even an electrolyte disturbance, which can cause severe, even fatal, neurological problems.[31] Drinking too much water, with insufficient salt intake, puts a person at risk of water intoxication (hyponatremia). Salt is even sometimes used as a health aid, such as in treatment of dysautonomia.[32]

    The risk for disease due to insufficient or excessive salt intake varies because of biochemical individuality. Some have asserted that while the risks of consuming too much salt are real, the risks have been exaggerated for most people, or that the studies done on the consumption of salt can be interpreted in many different ways.[33] [34]

    Many (though not all scientists)[35] believe that excess salt consumption has been linked to:

    • exercise-induced asthma.[36]
    • heartburn[37].
    • osteoporosis: One report shows that a high salt diet does reduce bone density in women.[38]. Yet "While high salt intakes have been associated with detrimental effects on bone health, there are insufficient data to draw firm conclusions." ([39], p3)
    • Gastric cancer (Stomach cancer) is associated with high levels of sodium, "but the evidence does not generally relate to foods typically consumed in the UK." ([39], p18) However, in Japan, salt consumption is higher.[40]
    • hypertension (high blood pressure): "Since 1994, the evidence of an association between dietary salt intakes and blood pressure has increased. The data have been consistent in various study populations and across the age range in adults." ([39] p3). A large scale study from 2007 has shown that people with high-normal blood pressure who significantly reduced the amount of salt in their diet decreased their chances of developing cardiovascular disease by 25% over the following 10 to 15 years. Their risk of dying from cardiovascular disease decreased by 20%.[41]
    • left ventricular hypertrophy (cardiac enlargement): "Evidence suggests that high salt intake causes left ventricular hypertrophy, a strong risk factor for cardiovascular disease, independently of blood pressure effects." ([39] p3) "…there is accumulating evidence that high salt intake predicts left ventricular hypertrophy." ([42], p12) Excessive salt (sodium) intake, combined with an inadequate intake of water, can cause hypernatremia. It can exacerbate renal disease.[31]
    • edema (BE: oedema): A decrease in salt intake has been suggested to treat edema (fluid retention).[31][43]
    • duodenal ulcers and gastric ulcers[44]
    • Death. Ingestion of large amounts of salt in a short time (about 1 g per kg of body weight) can be fatal. Salt solutions have been used in ancient China as a method of suicide (especially by the nobility, since salt was quite valuable). Deaths have also resulted from attempted use of salt solutions as emetics, forced salt intake, and accidental confusion of salt with sugar in child food.[45]

    Some scientists believe that excess salt intake has no ill health effect, as an adult will be able to remove salt from the body through the kidneys into the urine [35].

    Sea salt (an unrefined form of salt made by evaporating sea water) is often sold for use as a condiment. Sea salt contains trace amounts of other minerals which are removed in the refining process. Certain sea salts are also used in the production of bath salts and cosmetic products.

    Rock and sea salt is usually referred and sold as Natrum Muriaticum in homeopathy, and purported by followers to be a deep acting and powerful curative when taken over long periods of time.

    Some isolated cultures, such as the Yanomami in South America, have been found to consume little salt, possibly an adaptation originated in the predominantly vegetarian diet of human primate ancestors.[46]

    Recommended intake

    Sea salt and peppercorns.
    A salt mill for sea salt.

    In the United Kingdom the Scientific Advisory Committee on Nutrition (SACN) recommended in 2003 that, for a typical adult, the Reference Nutrient Intake is 4 g salt per day (1.6 g or 70 mmol sodium). However, average adult intake is two and a half times the Reference Nutrient Intake for sodium. SACN states, "The target salt intakes set for adults and children do not represent ideal or optimum consumption levels, but achievable population goals."[39] The Food Safety Authority of Ireland endorses the UK targets.[42]

    Health Canada recommends an Adequate Intake (AI) and an Upper Limit (UL) in terms of sodium,[47] as does the Auckland District Health Board in New Zealand.[48].

    The NHMRC in Australia was not able to define a recommended dietary intake (RDI). It defines an Adaquate Intake (AI) for adults of 460-920 mg/day and an Upper Level of intake (UL) of 2300 mg/day.[49]

    In the United States, the Food and Drug Administration itself does not make a recommendation,[50] but refers readers to Dietary Guidelines for Americans 2005. These suggest that US citizens should consume less than 2, 300 mg of sodium (= 2.3 g sodium = 5.8 g salt) per day.[51]

    Labeling

    UK: The Food Standards Agency defines the level of salt in foods as follows: "High is more than 1.5g salt per 100g (or 0.6g sodium). Low is 0.3g salt or less per 100g (or 0.1g sodium). If the amount of salt per 100g is in between these figures, then that is a medium level of salt." In the UK, foods produced by some supermarkets and manufacturers have ‘traffic light’ colors on the front of the pack: Red (High), Amber (Medium), or Green (Low).[52]

    USA: The FDA Food Labeling Guide stipulates whether a food can be labelled as "free", "low", or "reduced/less" in respect of sodium. When other health claims are made about a food (e.g. low in fat, calories, etc.), a disclosure statement is required if the food exceeds 480 mg of sodium per 'serving.'[53]

    Campaigns

    In 2004, Britain's Food Standards Agency started a public health campaign called "Salt - Watch it", which recommends no more than 6g of salt per day; it features a character called Sid the Slug and was criticised by the Salt Manufacturers Association (SMA).[54] The Advertising Standards Authority did not uphold the SMA complaint in its adjudication.[55]. In March 2007, the FSA launched the third phase of their campaign with the slogan "Salt. Is your food full of it?" fronted by comedienne Jenny Eclair.[56]

    The Menzies Research Institute in Tasmania, Australia, maintains a website [57] dedicated to educating people about the potential problems of a salt-laden diet.

    Consensus Action on Salt and Health (CASH)[58] established in 1996, actively campaigns to raise awareness of the harmful health effects of salt. The 2008 focus includes raising awareness of high levels of salt hidden in sweet foods and marketed towards children.[59]

    Salt substitutes

    Salt intake can be reduced by simply reducing the quantity of salty foods in a diet, without recourse to salt substitutes. Salt substitutes have a taste similar to table salt and contain mostly potassium chloride, which will increase potassium intake. Excess potassium intake can cause hyperkalemia. Various diseases and medications may decrease the body's excretion of potassium, thereby increasing the risk of hyperkalemia. Those who have kidney failure, heart failure or diabetes should seek medical advice before using a salt substitute. One manufacturer, LoSalt, has issued an advisory statement[60] that those taking the following prescription drugs should not use a salt substitute: Amiloride, Triamterene, Dytac, Spironolactone (Brand name Aldactone), Eplerenone and Inspra.

    Production

    Salt output in 2005

    Salt is produced by evaporation of seawater or brine from other sources, such as brine wells and salt lakes, and by mining rock salt, called halite. In 2002, total world production was estimated at 210 million tonnes, the top five producers being the United States (40.3 million tonnes), China (32.9), Germany (17.7), India (14.5), and Canada (12.3).[61] Note that these figures are not just for table salt but for sodium chloride in general.

    Salt disturbance in coastal industries

    The omnipresence of salt posts a problem in any coastal coating application. Salts that are trapped under a coating cause great problems in coating adhesion. Costs can reach staggering amounts. Naval authorities and ship builders keep a close eye on salt concentrations on surfaces during construction. Maximum salt concentrations on surfaces are dependent on the authority and application. The IMO regulation is mostly used and sets salt levels to a maximum of 50 mg/m2 soluble salts measured as sodium chloride. These measurements are done by means of a Bresle test.

    See also

    A ship loading salt from a terminal.

    Notes

    1. ^ a b Barber 1999:136
    2. ^ a b c d e Kurlansky 2002
    3. ^ Onbekende Wereld by Wim Offeciers (based on Doucan Gersi's travels)
    4. ^ Included among the other, less well-known continental salt sites with hal(l)- in their names are Reichenhall and Schwäbisch Hall in Germany, and Hall in Austria. (Barber 1999:137)
    5. ^ Barber 1999:135–137
    6. ^ Kurlansky 2002:52–55
    7. ^ "The American Heritage Dictionary of the English Language, 4th edition". Answers.com. http://www.answers.com/salary. Retrieved on 2008-12-14. 
    8. ^  "Salt". Catholic Encyclopedia. New York: Robert Appleton Company. 1913. http://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/Salt. 
    9. ^ "10+1 Things you may not know about Salt", Epikouria Magazine, Fall/Winter 2006
    10. ^ "10+1 Things you may not know about Salt", Epikouria Magazine, Fall/Winter 2006
    11. ^ Sea Salt is good for you
    12. ^ Iodine in non-iodized sea salt
    13. ^ European Salt Producers' Association http://www.eu-salt.com/index3.htm
    14. ^ Roskill Information Services http://www.roskill.com/reports/salt
    15. ^ Salt [ NaCl ] made the world go round
    16. ^ Nauticus - Weather Curriculum
    17. ^ UK Salt Manufacturers' Association http://www.saltsense.co.uk/aboutsalt-what01.htm
    18. ^ The Salt Manufacturers Association ::: saltsense, salt history, salt manufacture, salt uses, sodium. Key information on salt from the Salt Industry
    19. ^ The Salt Manufacturers Association ::: saltsense, salt history, salt manufacture, salt uses, sodium. Key information on salt from the Salt Industry
    20. ^ Halen Môn sea salt information page
    21. ^ Discussions of the safety of sodium hexaferrocyanate in table salt
    22. ^ HE-620
    23. ^ Nutritional analysis provided with Tesco Table Salt, from Tesco Stores Ltd (UK) states 38.9% sodium by weight which equals 98.9% sodium chloride
    24. ^ Table
    25. ^ "Rice in Salt Shakers". Ask a Scientist. http://www.newton.dep.anl.gov/askasci/gen01/gen01420.htm. Retrieved on 2008-07-29. 
    26. ^ What is Salt?, Salt Institute, 2008
    27. ^ The Seattle Times: Pacific Northwest Magazine
    28. ^ Iodized Salt
    29. ^ Iodized Salt
    30. ^ http://www.afssa.fr/Ftp/Afssa/26447-26448.pdf
    31. ^ a b c Australia: Better Health Channel (Australia, Victoria) Salt
    32. ^ Cleveland Clinic Health Information Center Dysautonomia page
    33. ^ Why Files article Salt and other wounds
    34. ^ Gary Taubes, "The (Political) Science of Salt", Science, 14 August 1998, Vol. 281. no. 5379, pp. 898 - 907
    35. ^ a b http://news.bbc.co.uk/2/hi/health/medical_notes/393201.stm
    36. ^ Exercise-induced asthma more clearly linked to high-salt diet
    37. ^ Everybody Study adds salt to suspected triggers for heartburn
    38. ^ High salt diet reduces bone density in girls
    39. ^ a b c d e Scientific Advisory Committee on Nutrition (SACN) Salt and Health (PDF)
    40. ^ Salt raises 'stomach cancer risk'
    41. ^ Cook NR, Cutler JA, Obarzanek E et al. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP). BMJ. 2007;334(7599):885. PMID 17449506 Free full-text
    42. ^ a b Food Safety Authority of Ireland Salt and Health: Review of the Scientific Evidence and Recommendations for Public Policy in Ireland
    43. ^ Australia: Better Health Channel (Australia, Victoria) Fluid retention
    44. ^ BBC High-salt diet link to ulcer risk 22 May 2007
    45. ^ Elisabeth Elena Türk, Friedrich Schulz, Erwin Koops, Axel Gehl and Michael Tsokos. Fatal hypernatremia after using salt as an emetic—report of three autopsy cases. Legal Medicine 2005, 7, 47-50. doi:10.1016/j.legalmed.2004.06.005
    46. ^ Yanomami Indians in the INTERSALT study, (accessed13 January 2007)
    47. ^ Health Canada Dietary Reference Intakes
    48. ^ Auckland District Health Board Public Health Nutrition Advice (PDF)
    49. ^ NHMRC Reference Nutrient Values, Sodium
    50. ^ U. S. Food and Drug Administration A Pinch of Controversy Shakes Up Dietary Salt
    51. ^ Department of Health and Human Services (HHS) and the Department of Agriculture (USDA) Dietary Guidelines for Americans 2005 "Sodium and Potassium"
    52. ^ Understanding labels
    53. ^ Food and Drug Administration A Food Labeling Guide--Appendix A
    54. ^ Salt Manufacturers Association press release New salt campaign under attack
    55. ^ Advertising Standards Authority Broadcast Advertising Adjudications: 20 April 2005 (PDF)
    56. ^ Salt TV ads
    57. ^ Salt Matters
    58. ^ "CASH Consensus Action on Salt". http://www.hyp.ac.uk/cash/. 
    59. ^ "Child health fears over high salt levels in sweet foods". 28 January 2008. http://www.guardian.co.uk/society/2008/jan/28/foodanddrink.healthandwellbeing. 
    60. ^ LoSalt Advisory Statement (PDF)
    61. ^ Susan R. Feldman. Sodium chloride. Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. Published online 2005. doi:10.1002/0471238961.1915040902051820.a01.pub2

    References

    Further reading

    • Kurlansky, Mark, and S. D. Schindler. The Story of Salt. New York, NY: G.P. Putnam's Sons, 2006. ISBN 0399239987—a children's book about salt.
    • Laszlo, Pierre. Salt: Grain of Life. Arts and traditions of the table. New York: Columbia University Press, 2001.
    • Department of Health, Dietary Reference Values for Food Energy and Nutrients for the UK: Report of the Panel on DRVs of the Committee on the Medical Aspects of Food Policy , The Stationery Office.

    External links

    Salt and health

    Government bodies

    Many other government bodies are listed in the References section above.

    Medical authorities
    Charities and campaigns
    Journalism
    Salt industry

     
    Translations: Salt
    Top

    Dansk (Danish)
    n. - salt, saltkar
    adj. - salt, saltagtig, salt-
    v. tr. - salte, nedsalte, komme salt på, krydre

    idioms:

    • salt away    nedsalte
    • salt cellar    saltkar
    • salt lick    saltsten
    • salt shaker    saltbøsse
    • salt water    saltvand, havvand
    • take with a pinch of salt    tage med et gran af salt
    • the salt of the earth    jordens salt
    • worth one's salt    være sin løn værd, gøre gavn for føden

    abbr. - forhandlinger om begrænsning af strategiske våben, SALT-aftalen

    Nederlands (Dutch)
    zout, zouten, pekelen, inmaken, gezouten met een korreltje zout nemen

    Français (French)
    n. - (Chim, Culin) sel, marin (arch)
    adj. - de/du sel, salé
    v. tr. - saler

    idioms:

    • salt away    saler, (fig) mettre en lieu sûr (de l'argent) (fam)
    • salt cellar    salière
    • salt down    saler, conserver dans le sel
    • salt lick    pierre salée, (Agric) bloc de sel
    • salt out    séparer une substance d'une solution par ajout de sel
    • salt shaker    salière
    • salt water    sel marin, de mer, marin
    • take with a pinch of salt    pas prendre (qch) pour argent comptant
    • the salt of the earth    le sel de la terre
    • worth one's salt    digne de ce nom

    abbr. - (abrév = Strategic Limitations Talks) négociations SALT

    Deutsch (German)
    n. - Salz, Würze, Seemann
    v. - salzen, pökeln
    adj. - salzig, gesalzen

    idioms:

    • salt away    auf die hohe Kante legen
    • salt cellar    Salzstreuer, Salzfaß
    • salt down    mit Salz konservieren
    • salt lick    Salzlecke
    • salt out    aussalzen
    • salt shaker    Salzstreuer
    • salt water    Salzwasser
    • take with a pinch of salt    nicht ganz wörtlich nehmen
    • the salt of the earth    anständig und rechtschaffen, das Salz der Erde
    • worth one's salt    etwas taugend

    abbr. - Verhandlungen über Begrenzung strategischer Waffen

    Ελληνική (Greek)
    n. - αλάτι, (χημ.) άλας, (μτφ.) σπιρτάδα πνεύματος, (πληθ.) (χημ.) άλατα, (καθομ.) θαλασσόλυκος
    v. - αλατίζω, παστώνω, (καθομ.) πλαστογραφώ, παραποιώ
    adj. - αλμυρός, (δάκρυα) πικρά, (πνεύμα) κοφτερό
    abbr. - αλατο-

    idioms:

    • salt away    παστώνω, καταχωνιάζω, αποταμιεύω
    • salt cellar    αλατιέρα, (μτφ.) λακκάκι λαιμού
    • salt lick    αλατότοπος, αλατόλακκος
    • salt shaker    (ΗΠΑ) αλατιέρα
    • salt water    αλατόνερο, θαλασσινό νερό
    • take with a pinch of salt    δεν παίρνω τοις μετρητοίς
    • the salt of the earth    το άλας της γης
    • worth one's salt    άξιος του μισθού μου

    Italiano (Italian)
    salare, sale, salato

    idioms:

    • salt away    metter da parte
    • salt cellar    saliera
    • salt lick    salgemma
    • salt shaker    saliera
    • salt water    acqua di mare, lacrime
    • smelling salts    sali, sali minerali
    • take with a pinch of salt    prendere cum grano salis
    • the salt of the earth    sale della terra
    • worth one's salt    efficace

    Português (Portuguese)
    n. - sal (m)
    v. - salgar

    idioms:

    • salt away    poupar
    • salt cellar    saleiro
    • salt lick    cocho de sal
    • salt shaker    saleiro
    • salt water    água salgada
    • take with a pinch of salt    manter nas devidas properções
    • the salt of the earth    o sal da terra
    • worth one's salt    incompetente

    Русский (Russian)
    соль, то, что вызывает интерес, солонка, морская вода, входящая в устье реки, солончак, соленый, соляной, засоленный, солончаковый, засаливать, консервировать, придавать пикантность

    idioms:

    • salt away    засаливать, припрятывать, складывать в кубышку
    • salt cellar    солонка
    • salt lick    соляной участок (у которого собираются дикие животные)
    • salt shaker    солонка с дырочками
    • salt water    обитающий в соленой воде, морской, соленый (об озере)
    • take with a pinch of salt    относиться к чему-л. с недоверием
    • the salt of the earth    соль земли
    • worth one's salt    быть достойным человеком, быть на высоте положения

    Español (Spanish)
    n. - sal, salado, curado, salero, sabor picante, agudeza, marisma, persona de experiencia
    adj. - salado, curado, en salmuera, salpreso, de sal, para la sal, salobre, salino, exagerada o cargada (cuenta o factura)
    v. tr. - salar, echar sal a, salpicar, sazonar, salpresar, dar sal, amañar, cargar precios exagerados en una factura

    idioms:

    • salt away    ahorrar, conservar en sal
    • salt cellar    salero (de mesa)
    • salt down    preservar algo agregando cantidades de sal
    • salt lick    salegar, lamedero
    • salt out    separar, una sustancia disuelta de una solución, agregando sal
    • salt shaker    salero
    • salt water    agua salada, agua salobre, lágrimas
    • take with a pinch of salt    admitir algo con reservas
    • the salt of the earth    la sal de la tierra (la gente mejor del mundo)
    • worth one's salt    merecer el pan que se come

    abbr. - charlas estratégicas de limitación de armas (Strategic Arms Limitation Talks)

    Svenska (Swedish)
    n. - salt, saltkar, skärpa, kvickhet
    v. - salta, strö salt på, salta in, krydda (språket)
    adj. - salt, salt-, saltad, magstark (bildl), väl kryddad (bildl), dryg (vard)
    abbr. - SALT-avtalen

    中文(简体)(Chinese (Simplified))
    限制战略武器谈判

    盐, 刺激, 风趣, 含盐的, 风趣的, 咸的, 加盐于, 用盐腌

    idioms:

    • salt away    腌制, 储存
    • salt cellar    盐瓶, 盐皿
    • salt lick    动物舐食岩盐之盐渍地
    • salt shaker    盐瓶
    • salt water    咸水, 海, 海水, 眼泪
    • take with a pinch of salt    对某事半信半疑
    • the salt of the earth    社会中坚, 高尚的人
    • worth one's salt    称职, 胜任

    中文(繁體)(Chinese (Traditional))
    abbr. - 限制戰略武器談判

    n. - 鹽, 刺激, 風趣
    adj. - 含鹽的, 風趣的, 鹹的
    v. tr. - 加鹽於, 用鹽醃

    idioms:

    • salt away    腌製, 儲存
    • salt cellar    鹽瓶, 鹽皿
    • salt lick    動物舐食岩鹽之鹽漬地
    • salt shaker    鹽瓶
    • salt water    咸水, 海, 海水, 眼淚
    • take with a pinch of salt    對某事半信半疑
    • the salt of the earth    社會中堅, 高尚的人
    • worth one's salt    稱職, 勝任

    한국어 (Korean)
    n. - 소금, 생기를 더해주는 것, 소금 그릇
    adj. - 소금을 함유한, 신랄한
    v. tr. - ~에 소금을 치다, ~을 염으로 처리하다, 실제보다 좋아 보이게 하다

    idioms:

    • salt away    소금에 절여 저장하다, 감추어 놓다
    • take with a pinch of salt    (남의 이야기 따위를) 에누리해서 듣다
    • the salt of the earth    세상을 정화하고 숭고하게 하는 사람, 사회의 중견, 엘리트들

    idioms:

    • salt Lake City    솔트레이크시티 (미국 Utah 주의 주도)

    abbr. - Strategic Arms Limitation Talks (전략 무기 제한 협정)

    日本語 (Japanese)
    n. - 塩, 塩類, 刺激, 機知, 薬用塩, 塩入れ
    v. - 塩をふりかける, 塩漬けにする, 味付けする
    adj. - 塩気のある, 塩漬けの, 海水につかった, 塩水の, 海水生の

    idioms:

    • salt away    塩漬けにする, しまっておく
    • salt cellar    塩入れ, 首の付け根
    • salt lick    家畜用岩塩
    • salt shaker    塩入れ
    • salt water    塩水, 海水
    • smelling salts    気付け薬
    • the salt of the earth    地の塩

    العربيه (Arabic)
    ‏(الاسم) ملح (فعل) يملح (صفه) مرير, لاذع, حاد (اختصار) Strategic Arms Limitaion Talks, محادثات الحد من الأسلحه الأسترتيجيه ألايمان بجزء مما يقال‏

    עברית (Hebrew)
    n. - ‮מלח, מלחייה, ימאי ותיק, פיקנטיות, מלח בישול‬
    adj. - ‮מוסיף טעם (לחיים), מלוח‬
    v. tr. - ‮המליח, הוסיף מלח, זרה מלח, תיבל (סיפור), רימה‬
    abbr. - ‮האמנה להגבלת נשק אסטרטגי‬


     
    Best of the Web: salt
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    Some good "salt" pages on the web:


    American Sign Language
    commtechlab.msu.edu
     
     
     
     

     

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