In one sentence: Our cells, particularly our muscles, use certain chemicals together with water to make sure that the electrical charges in our bodies work properly.
Sodium, chloride, potassium, calcium and magnesium are minerals which dissolve in water and form electrically charged electrolytes particles called “ions”. Maintaining the correct concentrations of these ions in and outside cells in the body is essential for transmitting electrical impulses along nerves and for muscle contraction. They allow us to perform all the “bioelectrical” functions such as moving, heart-beating, thinking, and seeing.
Salt (sodium chloride or NaCl) is one of the electrolytes that we all know very well. When salt is dissolved in water, the ions become separated. They are involved in fluid (water) balance in our body, if the balance is off, your nerves and muscles can suffer.
As well as the salt content of your bodily cells and surrounding fluids, calcium, magnesium and potassium are also important in fluid balance of your muscles. If your balance of electrolytes is wrong, you can get muscle cramps because the impulses are not firing correctly and muscles contract in spasms.
When the levels of sodium are too high, the body retains more water, which also raises the blood pressure (hypertension) as the increased water makes the heart work harder. Think of your home central heating system – if you topped up the water in the system too high, the pressure gauge would go up. This happens very slowly, and the biggest hazard is from weaning babies onto diets with too much salt. Given too much salt a baby may die. Human breast milk contains very little because we need very little. Given too much salt later on will re-set the kidneys and the systems which control blood pressure. Result – having a stroke at a younger age.
Sodium (mostly from salt) basically has to be kept out of cells. It is mostly in the blood stream, on its way to the kidneys. You only need perhaps 1 gram of salt daily, but our diets commonly contain 8-10 grams, and sometimes even more because salt has been put into so many manufactured foods.
Potassium is the main electrolyte in the fluid inside your cells, with less potassium than sodium in the fluids outside your cells).
If you become dehydrated (less water in the body) the electrolytes in your blood system (outside the cells) become more concentrated. This is detected by your thirst receptors in your brain, so you become thirsty. At the same time a hormone (‘antidiuretic hormone’ or ADH) is released, which reduces the water loss in urine being produced by the kidneys, to begin to correct the dehydration. ADH often causes headaches.
Did you know? A high salt intake makes you thirsty as it makes your blood more concentrated, so we drink more water/fluid to allow excess salt to be processed by our kidneys and passed out in urine.
Did you know? In hot climates, if we exercise and sweat a lot, a hormone called aldosterone works on our sweat glands to avoid losing too much sodium. Your sweat is less salty, and you don’t need to eat more salt.
Did you know? Chlorine is actually a poisonous green gas, but when it is combined with sodium (a soft metal), the combined chemical is sodium chloride, or table salt. So salt contains sodium but they aren’t quite the same thing.
Did you know? Food labels which show the sodium content of a food are not telling the full story. You have to multiply grams of sodium by 2.5 to get the grams of salt present. 1 g sodium means there are 2.5 g salt.