Why do we feel relief when we gargle with salt in hot water when suffering from throat pain?
Neyveli, Tamil Nadu
Soreness in the throat can cause throat pain. Soreness of throat is generally due to the infection of the bacterium called Streptococcus. So it is called strep throat. A strep throat is usually inflamed due to bacteria making widespread damage on our soft tissues or mucosa.
These inflammations (known as edemas) are usually filled with water. When we gargle with warm salt water that is saltier than our body fluids (hypertonic solution), through osmosis the salt draws out the edema fluid.
The principle behind it is that if a porous partition separates dilute and concentrated solutions then the dilute solution permeates through the porous partition into the concentrated solution.
This process does not stop till the concentration of both the solutions is equal. Salt water is more concentrated than the water in bacteria. The membrane of the cell of inflammatory tissue acts as a porous partition. So the salt draws water from the swollen cells that are causing pain and the inability to swallow foods.
Not only that, it will also draw water from the bacteria. When the bacteria gradually lose their body fluid they cannot remain active after dehydration. So they wither and die. This phenomenon is called plasmolysis.
The other benefits are; when the salt water enters the throat, the solution helps to neutralize acids in the throat, restoring the natural pH balance that had been disrupted by the sore throat.
By doing this, the burning sensations are relieved and the mucous membranes become less irritated, which can speed healing.
In addition to neutralizing acid, the salt water gargle helps to wash away unwanted mucus and increase the blood flow to the throat. The capillaries then become dilated, which allows for faster circulation of infection-fighting cells.
Instead of table-salt-dissolved water it is better to gargle with hypertonic saline water which contains two tea spoons of table salt and one tea spoon of baking soda (sodium bicarbonate, not baking powder) dissolved in 200 ml of purified water.
The sodium bicarbonate helps to improve the mucous-solvent properties of the irrigating solution.
The warm water and salt grains bathing in our throat may feel good. But too much salt can harm our mucosa. So moderate gargling is advised.
Moreover gargling with salt water does not actually help to heal the strep throat like a medicine would, but it does provide temporary relief. If we do not experience relief as a result of the salt water gargling and if the pain persists we must consult a doctor to get proper antibiotic treatment.
Editor, Research Journal of Biological Sciences
J.J. College of Arts and Science
Pudukkottai, Tamil Nadu