Both sea
salt and rock salt were well known to the ancient Greeks, who observed that
eating salty food affected basic body functions such as digestion and excretion;
this led to salt being used medically. Hippocrates strongly advocated salt in
the fifth century B.C. Salt-based remedies were thought to have expectorant
powers. A mixture of water, salt and vinegar was employed as an emetic. Drinking
a mixture of two-thirds cow's milk and one-third salt water in the mornings, on
an empty stomach, was recommended as a cure for diseases of the spleen. A
mixture of salt and honey was
applied topically to clean bad ulcers, and salt
water was used externally
against skin diseases and freckles. Hippocrates also mentions inhalation of
steam from salt water. So, two millennia ago, Greek medicine had already
discovered topical use of salt for skin lesions, drinking salty, mineralized
waters for digestive problems and inhaling salt for respiratory diseases.
The doctor and alchemist Paracelsus (1493–1541 A.D.) introduced an entirely new medical concept. He believed that external factors create disease and conceived a chemically oriented medical system, contrasting strongly with the philosophy of the herbal medicine that was prevalent at the time. However, he also advocated salt, saying only salted food could be digested properly. Paracelsus wrote: "The human being must have salt. He cannot be without salt. Where there is no salt, nothing will remain, but everything will tend to rot." He recommended salt water for the treatment of wounds and for use against intestinal worms. He claimed that a hip-bath in salt water was a superb remedy for skin diseases and itching: "This brine," he said, "is better than all the health spas arising out of nature." He described the diuretic effect of salt consumption and prescribed salt preparations of different strengths that were used, for instance, against constipation.
When water is available to get inside the cells freely, it's filtered from the salty reservoir outside the cells and is injected into the cells that are being stressed because of their water shortage. The design of our bodies is such that the extent of the reservoir of water outside the cells is expanded to make the extra water available for filtration and emergency injection into vital cells. The brain commands an increase in salt and water retention by the kidneys. This is how we can sometimes get an oedema when we don't drink enough water. We might be retaining it instead.
Initially, the process of water filtration and its delivery into the cells is more efficient at night when the body is horizontal. The collected water, which mostly pools in the legs, no longer has to fight the force of gravity. If reliance on this emergency cell hydration continues for long, the lungs start to become waterlogged at night and breathing becomes difficult; more pillows are needed at night to prop the body upright to sleep. This condition is the consequence of dehydration. However, it's possible to overload the system by drinking too much water at the start of a remedial program. Increases in water intake must be slow and spread out, until urine volume begins to increase at the same rate that water is consumed.When we drink enough water to pass clear urine, we also pass out a lot of the salt that was held back. This is how we can get rid of oedema fluid in the body: by drinking more water. Not diuretics -- but more water. This seems so non-intuitive that many people don't even believe this, but it's nevertheless true. Try it and find out for yourself.
If you have an extensive oedema -- with symptoms of your heart beginning to beat irregularly or rapidly after little physical effort -- your increase in water intake should be gradual and spaced out, but not withheld from your body. Salt intake should be limited for two or three days because your body is still in a kind of overdrive mode to retain it. Once the oedema has cleared up, salt should no longer be withheld.
Salt -- i.e. sodium -- is an electrolyte that your body needs. Electrolytes are minerals that dissolve in water and can carry electrical charges. Pure water does not conduct electricity, but water that contains salt does.
The three major electrolytes are sodium, potassium and chloride. Other body electrolytes are magnesium, calcium, zinc, and many others in very small amounts; these are the so-called trace minerals. They're electrically charged so they can carry nutrients into and out of your cells, and also carry messages along your nerves and help control your heartbeat.
Since your body is made mostly of water, these minerals can be found everywhere in your body. They're inside your cells, in the spaces between your cells, in your blood, your lymph and everywhere else. Since they hold an electrical charge, they can move through your cell membranes and thus carry other nutrients with them into the cells, and transport waste products and excess water out.