What happens when we eat something very salty?

‘Oh, I am thirsty! What have I eaten to make me so thirsty?’ This is certainly something you will have said, if not heard. The culprit is usually very salty food: like too many crisps. What has happened to this salt? During digestion, the salt passes into the blood. If there is too much salt in the blood, the alarm is given by the organs checking the blood’s composition. This alarm is transmitted to the thirst center in the brain. Only water taken in from outside the body can dilute this excess of salt, and remove it via the kidneys. But whilst waiting for a feeling of thirst to appear, and particularly whilst waiting for it to be quenched, water is drawn from the fluid which bathes the blood cells, and some salt passes into this fluid. The water will be replaced in this fluid, shortly after a drink has been taken.
The habit of eating very salty food can cause a reaction in the body: the fluid in which the cells are bathed becomes more plentiful, the tissues ‘swell’, particularly those under the skin. This swelling, often noticeable in ankles and fingers, is caused by excess salt. It is neither healthy nor nice to look at. In addition, the control mechanisms which keep the salt level in the blood normal, may introduce a secretion, or hormone, which increases the blood pressure. This increase in blood pressure is called ‘hypertension’. It may be slight, brief and not dangerous. Or it may become permanent and cause many health problems. This is the reason why someone with high blood pressure is put on to a salt-free diet. This may be enough to reduce the pressure, if it is caused solely by poor eating habits.