Salting It Away.
The use of dietary salt is hotly-debated with the media leading a near-hysterical popular antipathy towards it.
Scientists, on the other hand, have shown repeatedly that it is crucial to maintaining homeostasis - the internal balning acts that makes continued living possible.
It's also enlightening to discover that history, too, approves of the mineral; the wise old Greeks and the all-conquering Romans of classical times both viewed salt as a precious commodity.
The Greeks often bartered with the mineral, usually for slaves hence the derogatory term of someone being "not worth his salt". The globe-spanning legionary, meanwhile, received at least part of his pay in salt his salarium, or "salary".
Its influence and value also were known in the Middle East: the words, "war" and "peace" are derived form the ancient Arabic and Hebrew for salt and bread.
While Mankind was hunter and a forager, the salt (and especially the sodium) requirements were met largely through the fish and meat they caught and ate. The Bedouin, Masai and Zulu peoples continued this prehistoric tradition until relatively recently - that hunters in Greenland began eating salt as a separate component even later, with the introduction of whaling in the seventeenth century.
It was the coming of agriculture, civilisation and the accompanying fall in meat intake (in around 10 000 B.C.E) that encouraged the search for, processing of and trade in salt.
It has been suggested that the regions of Mesopotamia, the "Cradle of Civilisation", and the Mediterranean were ideal for this advent of city life. This is because, in addition to fertile river valleys, the urban populations near deserts and in "arid" zone climates made discovery of undissolved salt sources possible.
In wetter climes, these deposits would more likely be dissolved into the soil and bodies of water.
Up until the nineteenth century, salt was one the few methods of preserving food. There is evidence that people had been adding salt to stop food going off by 2000 B.C.E,
Fruits and vegetables were dried, cereal grains were parched and fish and game were salted and dried. In addition, it was used to make delicacies such as salted olives.
All the old religious cults - pagan, Mithraic, Vedic and, most notably, Judaic - made a point of demanding that meat offerings be thoroughly dried to kill all bacteria.
Typically a carcass is strung up to drain the blood. This still leaves more than a fifth of the body fluids, along with dangerous microbes such as E. coli, salmonella and the BSE (Mad Cow Disease) pathogen. Jewish Kosher [spoken] law stipulated the salting procedure in addition to osmotic dehydration to extract the last drops of tissue liquids.
Although salt is one of the most common minerals on the earth, supplies remained short until the modern era.
Salty springs and lakes evaporate, leaving crystals that can be collected. It can also be extracted from sea water or from wells tapping underground supplies of salty water by boiling. In places, they are simply collected or even mined.
Such processes are laborious and time-consuming. This, naturally made salt an expensive item, as did the cost of cartage. Whilst not exactly a luxury item, more a staple, it made very wealthy people of the traders who dealt in it. This trade was later 'nationalised' by the Romans and Chinese.
Intake peaked in the nineteenth century, with people salting away eighteen grammes each day on meat and fish like bacon and ham. This is three times the level currently recommended by the British Food Standards Agency.
Increased consumption of salt led to an interesting theory as crystallized salt used for food preservation has a chlorine-to-bromine ration of over 2000:1 - almost no bromine. Bromine acts as a sedative on the human nervous system, so some have speculated whether the bromine reduction stimulated activity and advances.
MR Bloch Salt Archives (http://www.salt.org.il/frame_phys.html) concluded:
i)Salt (NaCl) used as a condiment has little bromine
ii)Any salt free diet has a relatively-high bromide content
iii)The kidney reabsorbs bromide in preference to chlorides
iv)Sweat and saliva, have a higher bromide content, than blood and urine;
-sweating causes more bromide losses than of chlorides, counteracting the reverse effect of the kidneys. Hyponatremia is the name scientists give to low sodium concentrations in the blood.
Also, while we know no life can exist without water, it has been shown that humans, at least, also need electrolytes like salt; indeed too much water can kill!
"In an interview with Reuters Health, [Colonel John W. Gardner of the Office of the Armed Forces Medical Examiner, Maryland] explained that drinking too much water is dangerous because the body cannot excrete that much fluid. Excess water then goes to the bowel, which pulls salt into it from the body, diluting the concentration of salt in the tissues.
"Changing the concentration of salt, in turn, causes a shifting of fluids within the body, which can then induce a swelling in the brain. The swollen organ will then press against the bones of the skull, and become damaged.
"The researcher added that previous cases of water toxicity have been noted in athletes who consume excessive amounts in order to avoid heat stroke. In addition, certain psychiatric patients may drink too much water in an attempt to wash away their sins, or flush out poisons they believe have entered their bodies."
Far from being a dietary danger, salt is, thus, essential to healthy fluid balances in the the body. Hormonal maintenance ensures the proportion and concentration of salts in the blood remain constant. If a person eats too much, excess salt is excreted.
If there is too little, the body excretes more water to keep a constant salinity. Taken to extremes, desiccation and death result. It proved critical in Napoleon's withdrawal from Moscow in 1812. Thousands died on the march from dehydration, slow-healing wounds and lowered resistance to diseases.
A major criticism of salt concerns its alleged association with hypertension (high blood pressure. MR Bloch quotes from an article entitled "Low Urinary Salt Levels Linked With Higher Risk in Men with HBP [high blood pressure]:
"It was not until mid-1988 that medical journals began to publish the results of this massive effort, the Intersalt Study. These findings showed a scant relationship between sodium and blood pressure. "Salt has little importance in hypertension" headlined the accompanying editorial in the prestigious British Medical Journal.
"The Intersalt researchers measured urinary electrolytes and blood pressures in 10,079 individuals in 52 centres in 32 countries using standard methods and analysing the samples in a single laboratory. The head of the American Heart Association's Nutrition Committee and member of the U.S. Dietary Guidelines Advisory Committee summarised: "We're trying to back away from our salt recommendation without looking like fools."