Salt#Health effects

{{Main|History of salt}}

File:Salzproduktion-Halle.jpg (1670)]]

File:Salinas de Maras, Peru-20Sept2013.jpg, fed from a mineral spring and used for salt production since pre-Inca times ]]

All through history, the availability of salt has been pivotal to civilization. What is now thought to have been the first city in Europe is Solnitsata, in Bulgaria, which was a salt mine, providing the area now known as the Balkans with salt since 5400 BC.LA Times
[https://www.latimes.com/science/la-xpm-2012-nov-01-la-sci-sn-oldest-european-town-20121101-story.html Bulgarians find oldest European town, a salt production center] {{Webarchive |url=https://web.archive.org/web/20190504234136/https://www.latimes.com/science/la-xpm-2012-nov-01-la-sci-sn-oldest-european-town-20121101-story.html |date=4 May 2019 }} Salt was the best-known food preservative, especially for meat, for many thousands of years.{{sfnp|Barber|1999|p=136}} A very ancient salt-works operation has been discovered at the Poiana Slatinei archaeological site next to a salt spring in Lunca, Neamț County, Romania. Evidence indicates that Neolithic people of the Precucuteni Culture were boiling the salt-laden spring water through the process of briquetage to extract salt as far back as 6050 BC.{{sfnp|Weller|Dumitroaia|2005}} The salt extracted from this operation may have directly correlated with the rapid growth of this society's population soon after production began.{{sfnp|Weller|Brigand|Nuninger|2008|pp=225–30}} 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.{{sfnp|Kurlansky|2002|pp=18–19}}

There is more salt in animal tissues, such as meat, blood, and milk, than in plant tissues. Nomads who subsist on their flocks and herds do not eat salt with their food, but agriculturalists, feeding mainly on cereals and vegetable matter, need to supplement their diet with salt.{{cite web |url=http://www.britannica.com/EBchecked/topic/519712/salt-NaCl |title=Salt (NaCl) |last=Wood |first=Frank Osborne |publisher=Encyclopædia Britannica online |access-date=9 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20150502184136/http://www.britannica.com/EBchecked/topic/519712/salt-NaCl |archive-date=2 May 2015 |df=dmy-all}} With the spread of civilization, salt became one of the world's main trading commodities. It was of high value to the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites and other peoples of antiquity. In the Middle East, salt was used to seal an agreement ceremonially, and the ancient Hebrews made a "covenant of salt" with God and sprinkled salt on their offerings to show their trust in him.{{cite web |url=http://www.torahclass.com/archived-articles/1036-featured-article-sp-940659465 |title=Covenant of salt |last=Suitt |first=Chris |work=Rediscovering the Old Testament |publisher=Seed of Abraham Ministries |access-date=12 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20160305032105/http://torahclass.com/archived-articles/1036-featured-article-sp-940659465 |archive-date=5 March 2016 |df=dmy-all}} An ancient practice in time of war was salting the earth: scattering salt around in a defeated city to symbolically prevent plant growth. The Bible tells the story of King Abimelech who was ordered by God to do this at Shechem,{{cite journal |last=Gevirtz |first=Stanley |year=1963 |title=Jericho and Shechem: A Religio-Literary Aspect of City Destruction |journal=Vetus Testamentum |volume=13 |issue=1 |pages=52–62 |jstor=1516752 |doi=10.2307/1516752}} and various texts claim that the Roman general Scipio Aemilianus Africanus ploughed over and sowed the city of Carthage with salt after it was defeated in the Third Punic War (146 BC),{{cite book |last1=Ripley |first1=George |last2=Dana |first2=Charles Anderson |title=The New American Cyclopædia: a Popular Dictionary of General Knowledge |volume=4 |page=497 |year=1863 |url=https://books.google.com/books?id=bK4rAAAAYAAJ&q=carthage+sowing+salt&pg=PA497 |url-status=live |archive-url=https://web.archive.org/web/20150906143613/https://books.google.com/books?id=bK4rAAAAYAAJ&pg=PA497&dq=carthage+sowing+salt&q=carthage+sowing+salt |archive-date=6 September 2015 |df=dmy-all}} although this story is now considered to be entirely apocryphal.

Salt may have been used for barter in connection with the obsidian trade in Anatolia in the Neolithic Era.{{cite journal |last1=Golbas |first1=Alper |last2=Basobuyuk |first2=Zeynel |year=2012 |title=The role of salt in the formation of the Anatolian culture |journal=Batman University: Journal of Life Sciences |volume=1 |issue=1 |pages=45–54 |url=https://www.academia.edu/2340259 |url-status=live |archive-url=https://web.archive.org/web/20131211234508/http://www.academia.edu/2340259/Anadolu_Kultur_Olusumunda_Tuzun_Rolu-_The_Role_of_Salt_in_the_Formation_of_the_Anatolian_Culture |archive-date=11 December 2013 |df=dmy-all}} Salt was included among funeral offerings found in ancient Egyptian tombs from the third millennium BC, as were salted birds, and salt fish.{{sfnp|Kurlansky|2002|p=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 salted fish and salt from North Africa throughout their Mediterranean trade empire.{{sfnp|Kurlansky|2002|pp=44}} Herodotus described salt trading routes across Libya back in the 5th century BC. In the early years of the Roman Empire, roads were built for the transportation of salt from the salt imported at Ostia to the capital.{{cite news |title=A brief history of salt |url=http://content.time.com/time/magazine/article/0,9171,925341,00.html |newspaper=Time Magazine |date=15 March 1982 |access-date=11 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20160509161416/http://content.time.com/time/magazine/article/0%2C9171%2C925341%2C00.html |archive-date=9 May 2016 |df=dmy-all}}

In Africa, salt was used as currency south of the Sahara, and slabs of rock salt were used as coins in Abyssinia. The Tuareg have traditionally maintained routes across the Sahara especially for the transportation of salt by Azalai (salt caravans). The caravans still cross the desert from southern Niger to Bilma, although much of the trade now takes place by truck. Each camel takes two bales of fodder and two of trade goods northwards and returns laden with salt pillars and dates.{{cite web |url=http://www.bradshawfoundation.com/africa/tuareg_salt_caravans/ |title=Tuareg Salt Caravans of Niger, Africa |last=Paolinelli |first=Franco |publisher=Bradshaw Foundation |access-date=11 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20160803184735/http://www.bradshawfoundation.com/africa/tuareg_salt_caravans/ |archive-date=3 August 2016 |df=dmy-all}} In Gabon, before the arrival of Europeans, the coast people carried on a remunerative trade with those of the interior by the medium of sea salt. This was gradually displaced by the salt that Europeans brought in sacks, so that the coast natives lost their previous profits; as of the late 1950s, sea salt was still the currency best appreciated in the interior.{{cite book |last=Schweitzer |first=Albert |title=African Notebook |year=1958 |publisher=Indiana University Press}}

Salzburg, Hallstatt, and Hallein lie within {{cvt|17|km}} of each other on the river Salzach in central Austria in an area with extensive salt deposits. Salzach means "salt river" while Salzburg means "salt castle", both taking their names from the German word {{lang|de|Salz}}, salt. Hallstatt was the site of the world's first salt mine.{{cite web |url=http://www.virtualvienna.net/columns/billie/hallstatt/hallstatt.html |title=Hallstatt's White Gold: Salt |first=Billie Ann |last=Lopez |work=Virtual Vienna Net |access-date=3 March 2013 |url-status=dead |archive-url=https://web.archive.org/web/20070210142713/http://www.virtualvienna.net/columns/billie/hallstatt/hallstatt.html |archive-date=10 February 2007}} The town gave its name to the Hallstatt culture that began mining for salt in the area in about 800 BC. Around 400 BC, the townsfolk, who had previously used pickaxes and shovels, 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.{{sfnp|Barber|1999|p=136}}

The word salary comes from the Latin word for salt. The reason for this is unknown; a persistent modern claim that the Roman Legions were sometimes paid in salt is baseless.{{cite web |title=Economics of NaCl: Salt made the world go round |work=Mr Block Archive |author=Bloch, David |url=http://www.salt.org.il/frame_econ.html |access-date=19 December 2006 |df=dmy-all |archive-date=29 January 2007 |archive-url=https://web.archive.org/web/20070129144818/http://www.salt.org.il/frame_econ.html |url-status=live }}{{cite news |title=The history of salt production at Droitwich Spa |work=BBC |url=http://news.bbc.co.uk/local/herefordandworcester/hi/people_and_places/religion_and_ethics/newsid_8473000/8473037.stm |access-date=28 March 2011 |date=21 January 2010 |df=dmy-all |archive-date=22 February 2014 |archive-url=https://web.archive.org/web/20140222150314/http://news.bbc.co.uk/local/herefordandworcester/hi/people_and_places/religion_and_ethics/newsid_8473000/8473037.stm |url-status=live }} The word salad literally means "salted", and comes from the ancient Roman practice of salting leaf vegetables.{{sfnp|Kurlansky|2002|pp=64}}

Wars have been fought over salt. Venice won the Salt War (1304) with Padua over supplying the product in certain areas and the War of Ferrara (1482–1484) for the same reason.{{cite book |last1=Fontana |first1=Emanuele |title=Dizionario Biografico degli Italiani - Volume 81 |date=2014 |publisher=Treccani |url=https://www.treccani.it/enciclopedia/paolino-da-venezia-vescovo-di-pozzuoli_(Dizionario-Biografico)/ |chapter=PAOLINO da Venezia, vescovo di Pozzuoli}} It played a role in the American Revolution and the San Elizario Salt War. Cities on overland trade routes grew rich by levying duties, and towns like Liverpool flourished on the export of salt extracted from the salt mines of Cheshire.{{cite web |url=http://www.igg.org.uk/gansg/12-linind/salt.htm |title=Salt |last=Smith |first=Mike |year=2003 |work=Goods & Not So Goods: Lineside Industries |access-date=15 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20111124114738/http://www.igg.org.uk/gansg/12-linind/salt.htm |archive-date=24 November 2011 |df=dmy-all}} Various governments have at different times imposed salt taxes on their peoples. The voyages of Christopher Columbus are said to have been financed from salt production in southern Spain, and the oppressive salt tax in France was one of the causes of the French Revolution. After being repealed, this tax was reimposed by Napoleon when he became emperor to pay for his foreign wars, and was not finally abolished until 1946.{{cite web |url=http://mygeologypage.ucdavis.edu/cowen/~gel115/salt.html |title=The Importance of Salt |last=Cowen |first=Richard |date=1 May 1999 |access-date=15 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20160507083302/http://mygeologypage.ucdavis.edu/cowen/~GEL115/salt.html |archive-date=7 May 2016 |df=dmy-all}} In 1930, Mahatma Gandhi led a crowd of 100,000 protestors on the "Dandi March" or "Salt Satyagraha", during which they made their own salt from the sea as a demonstration of their opposition to the colonial salt tax. This act of civil disobedience inspired numerous Indians and transformed the Indian independence movement into a national struggle.{{sfnp|Dalton|1996|p=72}}

{{Anchor|Chemistry}}

{{main|Sodium chloride}}

File:Single grain of table salt (electron micrograph).jpg image of a grain of table salt]]

Salt is mostly sodium chloride (NaCl). Sea salt and mined salt may contain trace elements. Mined salt is often refined. Salt crystals are translucent and cubic in shape; they normally appear white but impurities may give them a blue or purple tinge. When dissolved in water sodium chloride separates into Na⁺ and Cl⁻ ions, and the solubility is 359 grams per litre.{{cite encyclopedia |url=http://www.britannica.com/EBchecked/topic/519712/salt-NaCl |title=Salt (NaCl) |last1=Wood |first1=Frank Osborne |last2=Ralston |first2=Robert H. |encyclopedia=Encyclopædia Britannica |access-date=16 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20150502184136/http://www.britannica.com/EBchecked/topic/519712/salt-NaCl |archive-date=2 May 2015 |df=dmy-all}} From cold solutions, salt crystallises as the dihydrate NaCl·2H₂O. Solutions of sodium chloride have very different properties from those of pure water; the freezing point is −21.12 °C (−6.02 °F) for 23.31 wt% of salt, and the boiling point of saturated salt solution is around 108.7 °C (227.7 °F).{{sfnp|Westphal|Kristen|Wegener|Ambatiello|2010}}

{{See also|List of edible salts|Salt substitute}}

File:Comparison of Table Salt with Kitchen Salt.png. Shows a typical salt shaker and salt bowl with salt spread before each on a black background.]]

Salt is essential to the health of humans and other animals, and it is one of the five basic taste sensations.{{cite web |url=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Taste.html |title=The sense of taste |date=16 March 2013 |access-date=16 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20160408080806/http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Taste.html |archive-date=8 April 2016 |df=dmy-all}} It is known to uniformly improve the taste perception of food, including otherwise unpalatable food.{{cite book |url=https://www.ncbi.nlm.nih.gov/books/NBK50958/ |title=Strategies to Reduce Sodium Intake in the United States|section=3 — Taste and Flavor Roles of Sodium in Foods: A Unique Challenge to Reducing Sodium Intake |author=Institute of Medicine (US) Committee on Strategies to Reduce Sodium Intake |editor1=Jane E. Henney |editor2=Christine L. Taylor |editor3=Caitlin S. Boon |isbn=978-0-309-14806-1 |publication-date=2010 |publisher=National Academies Press |location=Washington, DC |accessdate=29 October 2022 |archive-date=9 May 2021 |archive-url=https://web.archive.org/web/20210509080305/https://www.ncbi.nlm.nih.gov/books/NBK50958/ |url-status=live}} Salt is used in many cuisines, and it is often found in salt shakers on diners' eating tables for their personal use on food. Salt is also an ingredient in many manufactured foodstuffs. Table salt is a refined salt containing about 97 to 99 percent sodium chloride.{{cite web |title=Tesco Table Salt 750g |url=http://www.tesco.com/superstore/xpi/8/xpi50042778.htm |publisher=Tesco |access-date=5 December 2010 |quote=Nutritional analysis provided with Tesco Table Salt states 38.9 percent sodium by weight which equals 97.3 percent sodium chloride |url-status=live |archive-url=https://web.archive.org/web/20090511004300/http://www.tesco.com/superstore/xpi/8/xpi50042778.htm |archive-date=11 May 2009 |df=dmy-all}}[http://www.wasalt.com.au/Table.html Table Salt] {{webarchive |url=https://web.archive.org/web/20070805064907/http://www.wasalt.com.au/Table.html |date=5 August 2007 }}. Wasalt.com.au. Retrieved 7 July 2011.[http://www.codexalimentarius.net/download/standards/3/CXS_150e.pdf The international Codex Alimentarius Standard for Food Grade Salt] {{webarchive |url=https://web.archive.org/web/20120314012629/http://www.codexalimentarius.net/download/standards/3/CXS_150e.pdf |date=14 March 2012 }}. (PDF). Retrieved 7 July 2011. Usually, anticaking agents such as sodium aluminosilicate or magnesium carbonate are added to make it free-flowing. Iodized salt, containing potassium iodide, is widely available. Some people put a desiccant, such as a few grains of uncooked rice{{cite web |url=http://www.newton.dep.anl.gov/askasci/gen01/gen01420.htm |title=Rice in Salt Shakers |publisher=Ask a Scientist |access-date=29 July 2008 |url-status=live |archive-url=https://web.archive.org/web/20110314162037/http://www.newton.dep.anl.gov/askasci/gen01/gen01420.htm |archive-date=14 March 2011 |df=dmy-all}} or a saltine cracker, in their salt shakers to absorb extra moisture and help break up salt clumps that may otherwise form.{{cite web |url=http://ww3.komotv.com/story/1454284/food-freshness?redirected=true |archive-url=https://web.archive.org/web/20110820105950/http://ww3.komotv.com/story/1454284/food-freshness?redirected=true |archive-date=20 August 2011 |title=Food Freshness |publisher=KOMO News |access-date=8 July 2011}}

Some table salt sold for consumption contains additives that address a variety of health concerns, especially in the developing world. The identities and amounts of additives vary from country to country. Iodine is an important micronutrient for humans, and a deficiency of the element can cause lowered production of thyroxine (hypothyroidism) and enlargement of the thyroid gland (endemic goitre) in adults or cretinism in children.{{sfnp|Vaidya|Chakera|Pearce|2011}} Iodized salt has been used to correct these conditions since 1924{{sfnp|Markel|1987}} and consists of table salt mixed with a minute amount of potassium iodide, sodium iodide, or sodium iodate. A small amount of dextrose may be added to stabilize the iodine.{{cite web |url=http://extension.psu.edu/food-safety/food-preservation/faq/canning-and-pickling-salt |title=Canning and Pickling salt |publisher=Penn State University |url-status=live |archive-url=https://web.archive.org/web/20130407164426/http://extension.psu.edu/food-safety/food-preservation/faq/canning-and-pickling-salt |archive-date=7 April 2013 |df=dmy-all}}; {{cite web |url=http://www.mortonsalt.com/faqs/food-salt-faqs |publisher=Morton Salt |title=FAQs |url-status=dead |archive-url=https://web.archive.org/web/20140927063741/http://www.mortonsalt.com/faqs/food-salt-faqs |archive-date=27 September 2014 |df=dmy-all}} Iodine deficiency affects about two billion people around the world and is the leading preventable cause of intellectual disabilities.{{cite news |url=https://www.nytimes.com/2006/12/16/health/16iodine.html |title=In Raising the World's I.Q., the Secret's in the Salt |last=McNeil |first=Donald G. Jr |date=16 December 2006 |work=The New York Times |access-date=4 December 2008 |url-status=live |archive-url=https://web.archive.org/web/20081209044238/http://www.nytimes.com/2006/12/16/health/16iodine.html |archive-date=9 December 2008 |df=dmy-all}} Iodized table salt has significantly reduced disorders of iodine deficiency in countries where it is used.{{cite web |title=Iodized salt |url=http://www.saltinstitute.org/Uses-benefits/Salt-in-Food/Essential-nutrient/Iodized-salt |publisher=Salt Institute |access-date=5 December 2010 |year=2009 |url-status=live |archive-url=https://web.archive.org/web/20130214101408/http://www.saltinstitute.org/Uses-benefits/Salt-in-Food/Essential-nutrient/Iodized-salt |archive-date=14 February 2013 |df=dmy-all}}

The amount of iodine and the specific iodine compound added to salt varies. In the United States, the Food and Drug Administration (FDA) recommends 150 micrograms of iodine per day for both men and women.{{Cite web |last= |first= |date= |title=21 Code of Federal Regulations 101.9 (c)(8)(iv) |url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=101.9 |access-date=2021-01-30 |website=www.accessdata.fda.gov |archive-date=4 March 2021 |archive-url=https://web.archive.org/web/20210304132252/https://www.accessdata.fda.gov/scrIpts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.9 |url-status=live }} US iodized salt contains 46–77 ppm (parts per million), whereas in the UK the recommended iodine content of iodized salt is 10–22 ppm.{{cite web |title=Discussion Paper on the setting of maximum and minimum amounts for vitamins and minerals in foodstuffs |url=http://ec.europa.eu/food/food/labellingnutrition/supplements/documents/akj_en.pdf |publisher=Directorate-General Health & Consumers |access-date=5 December 2010 |url-status=dead |archive-url=https://web.archive.org/web/20121103050102/http://ec.europa.eu/food/food/labellingnutrition/supplements/documents/akj_en.pdf |archive-date=3 November 2012 |df=dmy-all}}

Sodium ferrocyanide, yellow prussiate of soda, is sometimes added to salt as an anticaking agent. Such anticaking agents have been added since at least 1911 when magnesium carbonate was first added to salt to make it flow more freely.{{cite web |title=Morton Salt FAQ |url=http://www.mortonsalt.com/faqs/general-company-faqs#q3 |access-date=12 May 2007 |url-status=live |archive-url=https://web.archive.org/web/20120119105846/http://www.mortonsalt.com/faqs/general-company-faqs#q3 |archive-date=19 January 2012 |df=dmy-all}} The safety of sodium ferrocyanide as a food additive was found to be provisionally acceptable by the Committee on Toxicity in 1988.[https://api.parliament.uk/historic-hansard/written-answers/1993/may/05/table-salt Discussions of the safety of sodium hexaferrocyanate in table salt] {{webarchive |url=https://web.archive.org/web/20160304090336/http://hansard.millbanksystems.com/written_answers/1993/may/05/table-salt |date=4 March 2016 }}. api.parliament.uk (5 May 1993). Retrieved 7 July 2011. Other anticaking agents sometimes used include tricalcium phosphate, calcium or magnesium carbonates, fatty acid salts (acid salts), magnesium oxide, silicon dioxide, calcium silicate, sodium aluminosilicate and calcium aluminosilicate. Both the European Union and the United States Food and Drug Administration permitted the use of aluminium in the latter two compounds.{{cite web |first1=Wilella Daniels |last1=Burgess |first2=April C. |last2=Mason |url=http://www.ces.purdue.edu/extmedia/HE/HE-625.html |title=What Are All Those Chemicals in My Food? |publisher=School of Consumer and Family Sciences, Purdue University |access-date=27 February 2011 |url-status=dead |archive-url=https://web.archive.org/web/20060211210829/http://www.ces.purdue.edu/extmedia/HE/HE-625.html |archive-date=11 February 2006 |df=dmy-all}}

In "doubly fortified salt", both iodide and iron salts are added. The latter alleviates iron deficiency anaemia, which interferes with the mental development of an estimated 40% of infants in the developing world. A typical iron source is ferrous fumarate.{{sfnp|Westphal|Kristen|Wegener|Ambatiello|2010}} Another additive, especially important for pregnant women, is folic acid (vitamin B₉), which gives the table salt a yellow colour. Folic acid helps prevent neural tube defects and anaemia, which affect young mothers, especially in developing countries.{{sfnp|Westphal|Kristen|Wegener|Ambatiello|2010}}

A lack of fluoride in the diet is the cause of a greatly increased incidence of dental caries.{{sfnp|Selwitz|Ismail|Pitts|2007}} Fluoride salts can be added to table salt with the goal of reducing tooth decay, especially in countries that have not benefited from fluoridated toothpastes and fluoridated water. The practice is more common in some European countries where water fluoridation is not carried out. In France, 35% of the table salt sold contains added sodium fluoride.{{sfnp|Westphal|Kristen|Wegener|Ambatiello|2010}}

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Unrefined sea salt contains small amounts of magnesium and calcium halides and sulfates, traces of algal products, salt-resistant bacteria and sediment particles. The calcium and magnesium salts confer a faintly bitter overtone, and they make unrefined sea salt hygroscopic (i.e., it gradually absorbs moisture from air if stored uncovered). Algal products contribute a mildly "fishy" or "sea-air" odour, the latter from organobromine compounds. Sediments, the proportion of which varies with the source, give the salt a dull grey appearance. Since taste and aroma compounds are often detectable by humans in minute concentrations, sea salt may have a more complex flavour than pure sodium chloride when sprinkled on top of food. When salt is added during cooking however, these flavours would likely be overwhelmed by those of the food ingredients.{{sfnp|McGee|2004|p=642}} 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.{{cite web |title=References on food salt & health issues |url=http://www.saltinstitute.org/Articles-references/References-on-salt-issues/References-on-salt-issues/References-on-food-salt-health-issues |publisher=Salt Institute |access-date=5 December 2010 |year=2009 |url-status=dead |archive-url=https://web.archive.org/web/20100919163713/http://www.saltinstitute.org/Articles-references/References-on-salt-issues/References-on-salt-issues/References-on-food-salt-health-issues |archive-date=19 September 2010 |df=dmy-all}}

Salts have diverse mineralities depending on their source, giving each a unique flavour. Fleur de sel, a natural sea salt from the surface of evaporating brine in salt pans, has a distinctive flavour varying with its source. In traditional Korean cuisine, so-called "bamboo salt" is prepared by roasting salt{{sfnp|Livingston|2005|p=45}} in a bamboo container plugged with mud at both ends. This product absorbs minerals from the bamboo and the mud, and has been claimed to increase the anticlastogenic and antimutagenic properties of doenjang (a fermented bean paste).{{sfnp|Shahidi|Shi|Ho|2005|p=575}} Kosher or kitchen salt has a larger grain size than table salt and is used in cooking. It can be useful for brining, in bread or pretzel making, and as a scrubbing agent when combined with oil.{{cite web |url=http://www.saltworks.us/salt_info/kosher-salt.asp |title=Kosher Salt Guide |publisher=SaltWorks |year=2010 |url-status=live |archive-url=https://web.archive.org/web/20101224110615/http://saltworks.us/salt_info/kosher-salt.asp |archive-date=24 December 2010 |df=dmy-all}}

Salt is present in most foods, but in naturally occurring foodstuffs such as meats, vegetables and fruit, it is present in very small quantities. It is often added to processed foods (such as canned foods and especially salted foods, pickled foods, and snack foods or other convenience foods), where it functions as both a preservative and a flavouring. Dairy salt is used in the preparation of butter and cheese products.{{cite book |last1=Pieters |first1=A.J. |last2=Flint |first2=D. |last3=Garriott |first3=E.B. |last4=Wickson |first4=E.J. |last5=Lamson-Scribner |first5=F. |last6=Brackett |first6=G.B. |last7=Atwater |first7=H.W. |last8=Alvord |first8=H.E. |last9=Withcombe |first9=J. |last10=Howard |first10=L.O. |display-authors=5 |title=Experiment Station Work |publisher=U.S. Department of Agriculture |series=Bread and the Principles of Bread Making |year=1899 |url=https://books.google.com/books?id=l85CAQAAMAAJ&pg=RA5-PA28 |access-date=17 November 2015 |pages=28–30 |url-status=live |archive-url=https://web.archive.org/web/20160616193742/https://books.google.com/books?id=l85CAQAAMAAJ&pg=RA5-PA28 |archive-date=16 June 2016 |df=dmy-all}} As a flavouring, salt enhances the taste of other foods by suppressing the bitterness of those foods making them more palatable and relatively sweeter.{{cite journal |last1=Breslin |first1=P. A. S. |last2=Beauchamp |first2=G. K. |title=Salt enhances flavour by suppressing bitterness |journal=Nature |date=5 June 1997 |volume=387 |issue=6633 |pages=563 |doi=10.1038/42388 |pmid=9177340 |bibcode=1997Natur.387..563B |s2cid=205030709|doi-access=free }}

Before the advent of electrically powered refrigeration, salting was one of the main methods of food preservation. Thus, herring contains 67 mg sodium per 100 g, while kipper, its preserved form, contains 990 mg. Similarly, pork typically contains 63 mg while bacon contains 1,480 mg, and potatoes contain 7 mg but potato crisps 800 mg per 100 g. Salt is used extensively in cooking as a flavouring, and in cooking techniques such as with salt crusts and brining. The main sources of salt in the Western diet, apart from direct use, are bread and cereals, meat, and dairy products.{{cite book |last1=Buss |first1=David |last2=Robertson |first2=Jean |title=Manual of Nutrition |year=1973 |publisher=Her Majesty's Stationery Office |isbn=978-0-11-241112-3 |pages=37–38}}

In many East Asian cultures, salt is not traditionally used as a condiment.{{cite web |url=https://archive.seattletimes.com/archive/20010729/pfish29/the-salt-of-southeast-asia |work=The Seattle Times |title=The Salt of Southeast Asia |access-date=7 July 2011 |year=2001 |url-status=live |archive-url=https://web.archive.org/web/20160303223708/http://community.seattletimes.nwsource.com/archive/?date=20010729&slug=pfish29 |archive-date=3 March 2016 |df=dmy-all}} In its place, condiments such as soy sauce, fish sauce and oyster sauce tend to have a high sodium content and fill a similar role to table salt in western cultures. They are most often used for cooking rather than as table condiments.{{cite web |url=http://www.diet.com/g/asian-diet |title=Asian diet |publisher=Diet.com |access-date=7 July 2013 |url-status=live |archive-url=https://web.archive.org/web/20160611091524/http://www.diet.com/g/asian-diet |archive-date=11 June 2016 |df=dmy-all}}

{{See also|Taste receptor#Salt|Taste#Saltiness}}

Human salt taste is detected by sodium taste receptors present in taste bud cells on the tongue.{{Cite book |last1=Intake |first1=Institute of Medicine (US) Committee on Strategies to Reduce Sodium |url=https://www.ncbi.nlm.nih.gov/books/NBK50958/ |title=Taste and Flavor Roles of Sodium in Foods: A Unique Challenge to Reducing Sodium Intake |last2=Henney |first2=Jane E. |last3=Taylor |first3=Christine L. |last4=Boon |first4=Caitlin S. |date=2010 |publisher=National Academies Press (US) |language=en |access-date=4 April 2021 |archive-date=9 May 2021 |archive-url=https://web.archive.org/web/20210509080305/https://www.ncbi.nlm.nih.gov/books/NBK50958/ |url-status=live }} Human sensory taste testing studies have shown that proteolyzed forms of epithelial sodium channel (ENaC) function as the human salt taste receptor.{{Cite journal |last1=Shekdar |first1=Kambiz |last2=Langer |first2=Jessica |last3=Venkatachalan |first3=Srinivasan |last4=Schmid |first4=Lori |last5=Anobile |first5=Jonathan |last6=Shah |first6=Purvi |last7=Lancaster |first7=Amy |last8=Babich |first8=Olga |last9=Dedova |first9=Olga |last10=Sawchuk |first10=Dennis |display-authors=5 |date=2021-03-08 |title=Cell engineering method using fluorogenic oligonucleotide signaling probes and flow cytometry |url= |journal=Biotechnology Letters |volume=43 |issue=5 |pages=949–958 |doi=10.1007/s10529-021-03101-5 |issn=1573-6776 |pmc=7937778 |pmid=33683511}}

{{Main|Health effects of salt}}

Table salt is made up of just under 40% sodium by weight, so a 6{{nbsp}}g serving (1{{nbsp}}teaspoon) contains about 2,400{{nbsp}}mg of sodium.{{cite web |url=https://ndb.nal.usda.gov/ndb/foods/show?ndbno=02047 |title=National Nutrient Database for Standard Reference, Basic Report: 02047, Salt, table |publisher=United States Department of Agriculture |work=Agricultural Research Service, National Nutrient Database for Standard Reference |access-date=21 July 2018 |url-status=dead |archive-url=https://web.archive.org/web/20160426013021/https://ndb.nal.usda.gov/ndb/foods/show/277 |archive-date=26 April 2016 |df=dmy-all}} Sodium serves a vital purpose in the human body: via its role as an electrolyte, it helps nerves and muscles to function correctly, and it is one factor involved in the osmotic regulation of water content in body organs (fluid balance).{{cite web |url=https://www.nlm.nih.gov/medlineplus/dietarysodium.html |title=Dietary sodium |publisher=MedLinePlus |access-date=17 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20131019134642/http://www.nlm.nih.gov/medlineplus/dietarysodium.html |archive-date=19 October 2013 |df=dmy-all}} Most of the sodium in the Western diet comes from salt.{{cite web |url=https://www.cdc.gov/salt/ |title=Most Americans should consume less sodium |work=Salt |publisher=Centers for Disease Control and Prevention |access-date=17 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20131019175037/http://www.cdc.gov/salt/ |archive-date=19 October 2013 |df=dmy-all}} The habitual salt intake in many Western countries is about 10 g per day, and it is higher than that in many countries in Eastern Europe and Asia. The high level of sodium in many processed foods has a major impact on the total amount consumed.{{cite web |url=https://www.nice.org.uk/guidance/ph25/resources/guidance-prevention-of-cardiovascular-disease-pdf |title=Prevention of cardiovascular disease |date=1 June 2010 |publisher=National Institute for Health and Clinical Excellence |access-date=5 May 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150518063044/https://www.nice.org.uk/guidance/ph25/resources/guidance-prevention-of-cardiovascular-disease-pdf |archive-date=18 May 2015 |df=dmy-all}} In the United States, 75% of the sodium eaten comes from processed and restaurant foods, 11% from cooking and table use and the rest from what is found naturally in foodstuffs.{{cite web |url=https://www.cdc.gov/salt/food.htm |title=Sodium and food sources |work=Salt |publisher=Centers for Disease Control and Prevention |access-date=17 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20131019175038/http://www.cdc.gov/salt/food.htm |archive-date=19 October 2013 |df=dmy-all}}

Because consuming too much sodium increases risk of cardiovascular diseases, health organizations generally recommend that people reduce their dietary intake of salt.{{cite web |url=http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Sodium-and-Salt_UCM_303290_Article.jsp#.V1jHedQrJkg |title=Sodium and salt |publisher=American Heart Association |date=2016 |access-date=8 June 2016 |url-status=live |archive-url=https://web.archive.org/web/20160817025149/http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Sodium-and-Salt_UCM_303290_Article.jsp#.V1jHedQrJkg |archive-date=17 August 2016 |df=dmy-all}} High sodium intake is associated with a greater risk of stroke, total cardiovascular disease and kidney disease.{{cite journal |last1=Strazzullo |first1=Pasquale |last2=D'Elia |first2=Lanfranco |last3=Kandala |first3=Ngianga-Bakwin |last4=Cappuccio |first4=Francesco P. |year=2009 |title=Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies |journal=British Medical Journal |volume=339 |issue=b4567 |pages=b4567 |doi=10.1136/bmj.b4567 |pmc=2782060 |pmid=19934192}} A reduction in sodium intake by 1,000 mg per day may reduce cardiovascular disease by about 30 percent.{{cite book |title=Scientific Report of the 2015 Dietary Guidelines Advisory Committee |date=2015 |publisher=US Department of Agriculture |page=7 |url=http://www.health.gov/dietaryguidelines/2015-scientific-report/PDFs/Scientific-Report-of-the-2015-Dietary-Guidelines-Advisory-Committee.pdf |url-status=live |archive-url=https://web.archive.org/web/20160418002033/http://health.gov/dietaryguidelines/2015-scientific-report/PDFs/Scientific-Report-of-the-2015-Dietary-Guidelines-Advisory-Committee.pdf |archive-date=18 April 2016 |df=dmy-all}} In adults and children with no acute illness, a decrease in the intake of sodium from the typical high levels reduces blood pressure.{{cite journal |last1=He |first1=F.J. |last2=Li |first2=J. |last3=Macgregor |first3=G.A. |title=Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. |journal=BMJ (Clinical Research Ed.) |date=3 April 2013 |volume=346 |pages=f1325 |pmid=23558162 |doi=10.1136/bmj.f1325 |doi-access=free}}{{cite journal |last1=Aburto |first1=Nancy J. |last2=Ziolkovska |first2=Anna |last3=Hooper |first3=Lee |last4=Elliott |first4=Paul |last5=Cappuccio |first5=Francesco P. |last6=Meerpohl |first6=Joerg J. |display-authors=3 |year=2013 |title=Effect of lower sodium intake on health: systematic review and meta-analyses |journal=British Medical Journal |volume=346 |issue=f1326 |pages=f1326 |doi=10.1136/bmj.f1326 |pmid=23558163 |pmc=4816261}} A low sodium diet results in a greater improvement in blood pressure in people with hypertension.{{Cite journal |last1=Graudal |first1=N iels Albert |last2=Hubeck-Graudal |first2=Thorbjorn |last3=Jurgens |first3=Gesche |date=April 9, 2017 |title=Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterol, and triglyceride |journal=The Cochrane Database of Systematic Reviews |volume=4 |issue=4 |pages=CD004022 |doi=10.1002/14651858.CD004022.pub4 |issn=1469-493X |pmc=6478144 |pmid=28391629}}{{cite journal |last1=Adler |first1=A. J. |last2=Taylor |first2=F. |last3=Martin |first3=N. |last4=Gottlieb |first4=S. |last5=Taylor |first5=R.S. |last6=Ebrahim |first6=S. |title=Reduced dietary salt for the prevention of cardiovascular disease |journal=The Cochrane Database of Systematic Reviews |date=18 December 2014 |volume=12 |issue=12 |pages=CD009217 |pmid=25519688 |pmc=6483405 |doi=10.1002/14651858.CD009217.pub3}}

The World Health Organization recommends that adults should consume less than 2,000 mg of sodium (which is contained in 5{{nbsp}}g of salt) per day.{{cite web |url=https://www.who.int/mediacentre/news/notes/2013/salt_potassium_20130131/en/ |title=WHO issues new guidance on dietary salt and potassium |date=31 January 2013 |publisher=World Health Organization |access-date=17 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20160720052736/http://www.who.int/mediacentre/news/notes/2013/salt_potassium_20130131/en/ |archive-date=20 July 2016 |df=dmy-all}} Guidelines by the United States recommend that people with hypertension, African Americans, and middle-aged and older adults should limit consumption to no more than 1,500 mg of sodium per day and meet the potassium recommendation of 4,700 mg/day with a healthy diet of fruits and vegetables.{{cite book |title=Dietary Guidelines for Americans |date=2010 |publisher=U.S. Department of Agriculture & U.S. Department of Health and Human Services |page=24 |url=http://www.health.gov/dietaryguidelines/dga2010/DietaryGuidelines2010.pdf |access-date=29 April 2015 |quote=African Americans, individuals with hypertension, diabetes, or chronic kidney disease and individuals ages 51 and older, comprise about half of the U.S. population ages 2 and older. While nearly everyone benefits from reducing their sodium intake, the blood pressure of these individuals tends to be even more responsive to the blood pressure-raising effects of sodium than others; therefore, they should reduce their intake to 1,500 mg per day. |url-status=live |archive-url=https://web.archive.org/web/20160901170759/https://health.gov/dietaryguidelines/dga2010/dietaryguidelines2010.pdf |archive-date=1 September 2016 |df=dmy-all}}

While reduction of sodium intake to less than 2,300 mg per day is recommended by developed countries, one review recommended that sodium intake be reduced to at least 1,200 mg (contained in 3{{nbsp}}g of salt) per day, as a further reduction in salt intake led to a greater fall in systolic blood pressure for all age groups and ethnicities. Another review indicated that there is inconsistent/insufficient evidence to conclude that reducing sodium intake to lower than 2,300 mg per day is either beneficial or harmful.{{Cite book |url=https://www.nap.edu/read/18311/chapter/7#122 |title=5 Findings and Conclusions {{!}} Sodium Intake in Populations: Assessment of Evidence |publisher=The National Academies Press|language=en |doi=10.17226/18311|pmid=24851297 |url-status=live |archive-url=https://web.archive.org/web/20170516040201/https://www.nap.edu/read/18311/chapter/7#122 |archive-date=16 May 2017|df=dmy-all|year=2013 |isbn=978-0-309-28295-6 |author1=Committee on the Consequences of Sodium Reduction in Populations |last2=Food Nutrition |first2=Board |author3=Board on Population Health Public Health Practice |last4=Institute Of |first4=Medicine |last5=Strom |first5=B. L. |last6=Yaktine |first6=A. L. |last7=Oria |first7=M. }}

Evidence shows a more complicated relationship between salt and cardiovascular disease. "The association between sodium consumption and cardiovascular disease or mortality is U-shaped, with increased risk at both high and low sodium intake."{{cite journal |doi=10.1016/S0140-6736(16)30467-6 |pmid=27216139 |title=Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: A pooled analysis of data from four studies |journal=The Lancet |volume=388 |issue=10043 |pages=465–475 |year=2016 |last1=Mente |first1=Andrew |last2=O'Donnell |first2=Martin |last3=Rangarajan |first3=Sumathy |last4=Dagenais |first4=Gilles |last5=Lear |first5=Scott |last6=McQueen |first6=Matthew |last7=Diaz |first7=Rafael |last8=Avezum |first8=Alvaro |last9=Lopez-Jaramillo |first9=Patricio |last10=Lanas |first10=Fernando |last11=Li |first11=Wei |last12=Lu |first12=Yin |last13=Yi |first13=Sun |last14=Rensheng |first14=Lei |last15=Iqbal |first15=Romaina |last16=Mony |first16=Prem |last17=Yusuf |first17=Rita |last18=Yusoff |first18=Khalid |last19=Szuba |first19=Andrzej |last20=Oguz |first20=Aytekin |last21=Rosengren |first21=Annika |last22=Bahonar |first22=Ahmad |last23=Yusufali |first23=Afzalhussein |last24=Schutte |first24=Aletta Elisabeth |last25=Chifamba |first25=Jephat |last26=Mann |first26=Johannes F E. |last27=Anand |first27=Sonia S. |last28=Teo |first28=Koon |last29=Yusuf |first29=S. |display-authors=5 |s2cid=44581906 |url=https://www.researchgate.net/publication/303462194 |hdl=10379/16625 |hdl-access=free |access-date=3 October 2020 |archive-date=9 January 2022 |archive-url=https://web.archive.org/web/20220109063636/https://www.researchgate.net/publication/303462194_Associations_of_urinary_sodium_excretion_with_cardiovascular_events_in_individuals_with_and_without_hypertension_A_pooled_analysis_of_data_from_four_studies |url-status=live }} The findings showed that increased mortality from excessive salt intake was primarily associated with individuals with hypertension. The levels of increased mortality among those with restricted salt intake appeared to be similar regardless of blood pressure. This evidence shows that while those with hypertension should primarily focus on reducing sodium to recommended levels, all groups should seek to maintain a healthy level of sodium intake of between 4 and 5 grams (equivalent to 10-13 g salt) a day.

One of the two most prominent dietary risks for disability in the world are diets high in sodium.{{Cite journal |last1=Lim |first1=Stephen S. |last2=Vos |first2=Theo |last3=Flaxman |first3=Abraham D. |last4=Danaei |first4=Goodarz |last5=Shibuya |first5=Kenji |last6=Adair-Rohani |first6=Heather |last7=Amann |first7=Markus |last8=Anderson |first8=H. Ross |last9=Andrews |first9=Kathryn G. |date=15 December 2012 |title=A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010 |journal=The Lancet |volume=380 |issue=9859 |pages=2224–2260 |doi=10.1016/S0140-6736(12)61766-8 |pmc=4156511 |pmid=23245609}}

{{Main|Sodium chloride}}

Only a small percentage of the salt manufactured in the world is used in food. The remainder is used in agriculture, water treatment, chemical production, de-icing, and other industrial use cases.{{sfnp|Westphal|Kristen|Wegener|Ambatiello|2010}} In the practice of watering plants with salt as a fertilizer, applying a moderate concentration helps avoid potential toxicity; typically, {{convert|1|-|3|g}} per liter is considered safe and effective for most plants.{{cite journal|doi=10.1093/aob/mcu217|date=1 December 2014 |title=Sodium chloride toxicity and the cellular basis of salt tolerance in halophytes |last1=Flowers |first1=Timothy J. |last2=Munns |first2=Rana |last3=Colmer |first3=Timothy D. |journal=Annals of Botany |volume=115 |issue=3 |pages=419–431 |pmid=25466549 |pmc=4332607 }}{{cite journal|doi=10.1093/jxb/ert326|date=22 October 2013 |title=Sodium in plants: Perception, signalling, and regulation of sodium fluxes |last1=Maathuis |first1=Frans J. M. |journal=Journal of Experimental Botany |volume=65 |issue=3 |pages=849–858 |pmid=24151301 }}{{cite journal |doi=10.21273/HORTSCI.43.6.1888 |title=Sodium Chloride Effects on Growth, Morphology, and Physiology of Chrysanthemum (Chrysanthemum ×morifolium) |date=2008 |last1=Lee |first1=M. Kate |last2=Van Iersel |first2=Marc W. |journal=HortScience |volume=43 |issue=6 |pages=1888–1891 |doi-access=free }} Sodium chloride is one of the largest volume inorganic raw materials. It is a feedstock in the production of caustic soda and chlorine. These are used in the manufacture of PVC, paper pulp and many other inorganic and organic compounds. Salt is used as a flux in the production of aluminium. For this purpose, a layer of melted salt floats on top of the molten metal and removes iron and other metal contaminants. It is used in the manufacture of soaps and glycerine, where it is used to saponify fats. As an emulsifier, salt is used in the manufacture of synthetic rubber, and another use is in the firing of pottery, when salt added to the furnace vaporises before condensing onto the surface of the ceramic material, forming a strong glaze.{{cite web |url=http://www.wasalt.com.au/SaltUses.html |title=Salt uses |publisher=WA Salt Group |access-date=10 October 2013 |archive-url=https://web.archive.org/web/20131011054052/http://www.wasalt.com.au/SaltUses.html |archive-date=11 October 2013}}

When drilling through loose materials such as sand or gravel, salt may be added to the drilling fluid to provide a stable "wall" to prevent the hole collapsing. There are many other processes in which salt is involved. These include its use as a mordant in textile dying, to regenerate resins in water softening, for the tanning of hides, the preservation of meat and fish and the canning of meat and vegetables.{{cite web |url=http://www.ihs.com/products/chemical/planning/ceh/sodium-chloride.aspx |title=Sodium chloride |date=1 December 2008 |publisher=IHS Chemical |access-date=12 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20130325193515/http://www.ihs.com/products/chemical/planning/ceh/sodium-chloride.aspx |archive-date=25 March 2013 |df=dmy-all}}{{sfnp|Kostick|2011}}

{{See also|List of countries by salt production}}

file:2018-07-19 037 Sifto Salt Mine, Goderich ON Canada.jpg , Canada]]

Food-grade salt accounts for only a small part of salt production in industrialized countries (7% in Europe),{{cite web |url=http://eusalt.com/salt-uses |title=Salt Uses |publisher=European Salt Producers' Association |access-date=5 May 2015 |url-status=live |archive-url=https://web.archive.org/web/20150212060035/http://eusalt.com/salt-uses |archive-date=12 February 2015 |df=dmy-all}} although worldwide, food uses account for 17.5% of total production.{{cite web |url=http://www.roskill.com/reports/salt |title=Roskill Information Services |publisher=Roskill.com |date=30 March 2011 |access-date=7 July 2011 |url-status=dead |archive-url=https://web.archive.org/web/20030618234222/http://www.roskill.com/reports/salt |archive-date=18 June 2003 |df=dmy-all}}

In 2018, total world production of salt was 300 million tonnes, the top six producers being China (68 million), the United States (42 million), India (29 million), Germany (13 million), Canada (13 million) and Australia (12 million).{{cite report |last1=Bolen |first1=Wallace P.|chapter-url=https://prd-wret.s3-us-west-2.amazonaws.com/assets/palladium/production/atoms/files/mcs-2019-salt.pdf |chapter=Salt |title=US Geological Survey, Mineral Commodity Summaries |publisher=US Geological Survey |date=February 2019 |url-status=live |archive-url=https://web.archive.org/web/20190731194635/https://prd-wret.s3-us-west-2.amazonaws.com/assets/palladium/production/atoms/files/mcs-2019-salt.pdf |archive-date=31 July 2019 |df=dmy-all}}

The manufacture of salt is one of the oldest chemical industries.{{cite web |url=http://www.salt.org.il/arch.html |title=Salt made the world go round |work=Salt.org.il |date=1 September 1997 |access-date=7 July 2011 |url-status=live |archive-url=https://web.archive.org/web/20160405130434/http://www.salt.org.il/arch.html |archive-date=5 April 2016 |df=dmy-all}} A major source of salt is seawater, which has a salinity of approximately 3.5%.{{sfnp|Westphal|Kristen|Wegener|Ambatiello|2010}} This means that there are about {{cvt|35|g|oz}} of dissolved salts, predominantly sodium ({{chem|Na||+}}) and chloride ({{chem|Cl||-}}) ions, per kilogram (2.2 lbs) of water.{{sfnp|Millero|Feistel|Wright|McDougall|2008}} The world's oceans are a virtually inexhaustible source of salt, and this abundance of supply means that reserves have not been calculated. The evaporation of seawater is the production method of choice in marine countries with high evaporation and low precipitation rates. Salt evaporation ponds are filled from the ocean and salt crystals can be harvested as the water dries up. Sometimes these ponds have vivid colours, as some species of algae and other micro-organisms thrive in conditions of high salinity.{{cite web |url=http://visibleearth.nasa.gov/view.php?id=2631 |title=Salt Ponds, South San Francisco Bay |work=NASA Visible Earth |publisher=NASA |access-date=5 May 2015 |url-status=live |archive-url=https://web.archive.org/web/20160715085242/http://visibleearth.nasa.gov/view.php?id=2631 |archive-date=15 July 2016 |df=dmy-all |date=2009-08-11}}

Away from the sea, salt is extracted from the vast sedimentary deposits which have been laid down over the millennia from the evaporation of seas and lakes. These sources are either mined directly, producing rock salt, or are extracted by pumping water into the deposit. In either case, the salt may be purified by mechanical evaporation of brine. Traditionally, purification was achieved in shallow open pans that were heated to accelerate evaporation. Vacuum-based methods are also employed.{{sfnp|Kostick|2011}} The raw salt is refined by treatment with chemicals that precipitate most impurities (largely magnesium and calcium salts). Multiple stages of evaporation are then applied.[https://web.archive.org/web/20090409144219/http://www.saltsense.co.uk/aboutsalt-prod02.htm About salt: Production]. The Salt Manufacturers Association Some salt is produced using the Alberger process, which involves vacuum pan evaporation combined with the seeding of the solution with cubic crystals, and produces a grainy-type flake.{{cite encyclopedia |url=http://www.britannica.com/EBchecked/topic/12642/Alberger-process |title=Alberger process |encyclopedia=Manufacture of salt: Uses of artificial heat |publisher=Encyclopædia Britannica online |access-date=9 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20110223025143/http://www.britannica.com/EBchecked/topic/12642/Alberger-process |archive-date=23 February 2011 |df=dmy-all}} The Ayoreo, an indigenous group from the Paraguayan Chaco, obtain their salt from the ash produced by burning the timber of the Indian salt tree (Maytenus vitis-idaea) and other trees.{{sfnp|Schmeda-Hirschmann|1994}}

The largest mine operated by underground workings in the world is the Sifto mine, located mostly 550 meters below Lake Huron, in Goderich, Ontario (Canada). About seven million tons of salt are extracted from it annually.{{Cite book |last1=Calvo |first1=Miguel |title=Una pizca de sal |last2=Calvo |first2=Guiomar |publisher=Prames |year=2023 |isbn=978-84-8321-582-1 |location=Zaragoza, Spain |pages=114–115 |language=es |trans-title=A pinch of salt}} The Khewra Salt Mine in Pakistan has nineteen storeys, eleven of which are underground, and {{cvt|400|km}} of passages. The salt is dug out by the room and pillar method, where about half the material is left in place to support the upper levels. Extraction of Himalayan salt is expected to last 350 years at the present rate of extraction of around 385,000 tons per annum.The mine is also a major tourist attraction, receiving around a quarter of a million visitors a year.{{cite news |last=Pennington |first=Matthew |title=Pakistan salt mined old-fashioned way mine |url=http://seattletimes.nwsource.com/html/nationworld/2002159747_saltmine25.html |access-date=11 October 2013 |newspaper=The Seattle Times |date=25 January 2005 |url-status=live |archive-url=https://web.archive.org/web/20120725072022/http://seattletimes.nwsource.com/html/nationworld/2002159747_saltmine25.html |archive-date=25 July 2012 |df=dmy-all}}

File:Bo Kluea 01.jpg|Brine from salt wells is boiled to produce salt at Nan Province, Thailand

File:Piles of Salt Salar de Uyuni Bolivia Luca Galuzzi 2006 a.jpg|Salt mounds in Salar de Uyuni, Bolivia

File:Marakkanam Salt Pans.JPG|Sea-salt pans in Tamil Nadu, India

File:Chad Creating salt balls near Tigui DSC0596.jpg|Salt balls in Borkou province, Chad

File:Russian bread and salt.jpg at a Russian wedding ceremony]]

Salt has long held an important place in religion and culture. At the time of Brahmanic sacrifices, in Hittite rituals and during festivals held by Semites and Greeks at the time of the new moon, salt was thrown into a fire where it produced crackling noises.{{cite book |chapter-url=http://www.bookrags.com/research/salt-eorl-12/ |chapter=Research article: Salt |title=Encyclopedia of Religion |access-date=13 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20160304050505/http://www.bookrags.com/research/salt-eorl-12/ |archive-date=4 March 2016 |df=dmy-all}} The ancient Egyptians, Greeks and Romans invoked their gods with offerings of salt and water and some people think this to be the origin of Holy Water in the Christian faith.{{cite journal |year=2006 |title=10+1 Things you may not know about Salt |url=http://www.epikouria.com/issue3/article6-things.php |url-status=dead |journal=Epikouria |volume=Fall/Winter |issue=3 |archive-url=https://web.archive.org/web/20080704055740/http://www.epikouria.com/issue3/article6-things.php |archive-date=4 July 2008}} In Judaism, it is recommended to have either a salty bread or to add salt to the bread if this bread is unsalted when doing Kiddush for Shabbat. It is customary to spread some salt over the bread or dip it in a little salt when passing it around the table after the Kiddush.Naftali Silberberg [http://www.chabad.org/library/article_cdo/aid/484194/jewish/Why-dip-in-salt.htm Why is the Challah dipped in salt before it is eaten?] {{webarchive|url=https://web.archive.org/web/20120120034528/http://www.chabad.org/library/article_cdo/aid/484194/jewish/Why-dip-in-salt.htm|date=20 January 2012}}, Chabad.org To preserve the covenant between their people and God, Jews dip the Sabbath bread in salt. Salt plays a role within different Christian traditions. It is mandatory in the rite of the Tridentine Mass.s:Catholic Encyclopedia (1913)/Salt 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, and it is permitted to be added to the water "where it is customary" in the Roman Catholic rite of Holy water. The Bible makes multiple mentions of salt, both of the mineral itself and as a metaphor. Uses include the tale of how Lot's wife is turned into a pillar of salt when looking back at the cities of Sodom and Gomorrah as they are destroyed. In the New Testament, Jesus refers to his followers as the "salt of the earth".{{cite dictionary |last=McKenzie |first=John L. |chapter=Salt |title=Dictionary of the Bible |publisher=Simon & Schuster |year=1995 |isbn=0-684-81913-9 |pages=759–760}}

In Aztec mythology, Huixtocihuatl was a fertility goddess who presided over salt and salt water.{{cite web |url=http://www.amoxtli.org/cuezali/festivals.html |title=The Aztec Festivals: Toxcatl (Dryness) |last=Quipoloa |first=J. |year=2007 |work=The Aztec Gateway |access-date=18 March 2013 |url-status=usurped |archive-url=https://web.archive.org/web/20150916191933/http://www.amoxtli.org/cuezali/festivals.html |archive-date=16 September 2015 |df=dmy-all}} Salt is an auspicious substance in Hinduism and is used in ceremonies like house-warmings and weddings.{{cite news |title=What Lies Beneath |last=Gray |first=Steven |url=http://www.time.com/time/magazine/article/0,9171,2001007,00.html |newspaper=Time Magazine |date=7 December 2010 |access-date=13 March 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130817090849/http://www.time.com/time/magazine/article/0%2C9171%2C2001007%2C00.html |archive-date=17 August 2013 |df=dmy-all}} In Jainism, devotees lay an offering of raw rice with a pinch of salt before a deity to signify their devotion and salt is sprinkled on a person's cremated remains before the ashes are buried.{{cite web |url=http://www.finaljourneyseminars.com/?page_id=472 |title=The Final Journey: What to do when your loved one passes away |access-date=12 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20160306031827/http://www.finaljourneyseminars.com/?page_id=472 |archive-date=6 March 2016 |df=dmy-all}} Salt is believed to ward off evil spirits in Mahayana Buddhist tradition. When returning home from a funeral, a pinch of salt is thrown over the left shoulder as this prevents evil spirits from entering the house.{{cite web |url=http://www.cargill.com/salt/about/historyofsalt/religion/ |title=Religion: Chasing away evil spirits |work=History of salt |publisher=Cagill |access-date=13 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20140314070618/http://www.cargill.com/salt/about/historyofsalt/religion/ |archive-date=14 March 2014 |df=dmy-all}} In Shinto, {{nihongo|Shio|塩, lit. "salt"}} is used for ritual purification of locations and people (harae, specifically shubatsu), and small piles of salt are placed in dishes by entrances to ward off evil and to attract patrons.{{cite web |title=Harae - purification rites |url=https://www.bbc.co.uk/religion/religions/shinto/ritesrituals/harae.shtml |publisher=BBC |access-date=25 November 2024 |date=16 September 2009}}

{{Reflist}}

{{Refbegin |40em|indent=yes}}

• {{Cite book |last=Barber |first=Elizabeth Wayland |year=1999 |title=The Mummies of Ürümchi |location=New York |publisher=W.W. Norton & Co |isbn=0-393-32019-7 |oclc=48426519}}
• {{Cite book |last=Dalton |first=Dennis |title=Mahatma Gandhi: Selected Political Writings |publisher=Hackett Publishing Company |isbn=0-87220-330-1 |year=1996 |pages=71–73 |chapter=Introduction to Civil Disobedience |url=https://books.google.com/books?id=Er59fRsspgoC |access-date=27 June 2015 |archive-date=10 August 2016 |archive-url=https://web.archive.org/web/20160810152615/https://books.google.com/books?id=Er59fRsspgoC |url-status=live }}
• {{cite report |title=Salt |first=Dennis S. |last=Kostick |publisher=US Geological Survey |date=2011 |url=https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/mineral-pubs/salt/myb1-2011-salt.pdf |access-date=23 March 2024 |archive-date=10 November 2023 |archive-url=https://web.archive.org/web/20231110113818/http://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/mineral-pubs/salt/myb1-2011-salt.pdf |url-status=live }}
• {{Cite book |last=Kurlansky |first=Mark |year=2002 |title=Salt: A World History |location=New York |publisher=Walker & Co |isbn=0-8027-1373-4 |oclc=48573453}}
• {{cite book |last=Livingston |first=James V. |title=Agriculture and soil pollution: new research |publisher=Nova Publishers |year=2005 |isbn=1-59454-310-0 |url=https://books.google.com/books?id=W6ToDne5AsMC&pg=PA45 |access-date=27 June 2015 |archive-date=6 September 2015 |archive-url=https://web.archive.org/web/20150906112001/https://books.google.com/books?id=W6ToDne5AsMC&pg=PA45 |url-status=live }}
• {{cite journal |last=Markel |first=Howard |date=1987 |title='When it rains, it pours':Endemic Goiter, Iodized Salt and David Murray Cowie, MD.|journal= American Journal of Public Health |volume=77 |issue=2 |pages=219–229|doi=10.2105/AJPH.77.2.219 |pmid=3541654 |pmc=1646845 }}
• {{cite book |last=McGee |first=Harold |title=On Food and Cooking |publisher=Scribner |edition=2nd |year=2004 |isbn=9781416556374 |url=https://books.google.com/books?id=bKVCtH4AjwgC |access-date=27 June 2015 |archive-date=25 December 2020 |archive-url=https://web.archive.org/web/20201225060412/https://books.google.com/books?id=bKVCtH4AjwgC |url-status=live }}
• {{cite journal |journal=Deep Sea Research Part I: Oceanographic Research Papers |publisher=Elsevier |volume=55 |issue=1 |date=January 2008 |pages=50–72 |title=The composition of Standard Seawater and the definition of the Reference-Composition Salinity Scale |first1=Frank J. |last1=Millero |first2=Rainer |last2=Feistel |first3=Daniel |last3=Wright |first4=Trevor J. |last4=McDougall |doi=10.1016/j.dsr.2007.10.001|bibcode=2008DSRI...55...50M }}
• {{cite journal |last=Schmeda-Hirschmann |first=Guillermo |title=Tree ash as an Ayoreo salt source in the Paraguayan Chaco. |journal=Economic Botany |volume=48 |pages=159–162 |date=1994 |issue=2 |doi=10.1007/BF02908207|bibcode=1994EcBot..48..159S }}
• {{cite journal |journal=The Lancet |title=Dental caries |first1=Robert H |last1=Selwitz |first2=Amid I |last2=Ismail |first3=Nigel B |last3=Pitts |

pmid= 17208642 |doi=10.1016/S0140-6736(07)60031-2 |date=6 January 2007|volume=369 |issue=9555 |pages=51–59 }}

• {{cite book |last1=Shahidi |first1=Fereidoon |last2=Shi |first2=John |last3=Ho |first3=Chi-Tang |title=Asian functional foods |publisher=CRC Press |location=Boca Raton |year=2005 |isbn=0-8247-5855-2}}
• {{cite journal |title=The earliest salt production in the world: An early Neolithic exploitation in Poiana Slatinei-Lunca, Romania |journal=Antiquity |volume=79 |number=306 |date=December 2005 |url=https://www.researchgate.net/publication/281419381 |first1=Olivier |last1=Weller |first2=Gheorghe |last2=Dumitroaia }}
• {{cite conference |last1=Weller |first1=Olivier |last2=Brigand |first2=Robin |last3=Nuninger |first3=Laure |title=Spatial Analysis of Salt Springs Exploitation in Moldavian Pre-Carpatic Prehistory (Romania) |conference=Archædyn |date=June 2008 |url=http://hal.archives-ouvertes.fr/docs/01/06/64/23/PDF/Weller_Brigand_Archaedyn_Dijon_2008.pdf }} (Preprint)
• {{cite encyclopedia |encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry |doi=10.1002/14356007.a24_317.pub4 |first1=Gisbert |last1=Westphal |first2=Gerhard |last2=Kristen |first3=Wilhelm |last3=Wegener |first4=Peter |last4=Ambatiello |title=Sodium Chloride |date=January 2010 |isbn=978-3527306732}}
• {{cite journal |title=Treatment for primary hypothyroidism: current approaches and future possibilities. |doi=10.2147/DDDT.S12894 |first2=Ali J |last2= Chakera |first3=Simon HS |last3=Pearce |first1=Bijay |last1=Vaidya |date=2011 |journal=Drug Design, Development and Therapy |volume=6|pages=1–11 |doi-access=free |pmid=22291465 |pmc=3267517 }}

{{Refend}}

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