Salty food may not make you thirsty after all
The traditional wisdom that eating salty foods makes you thirsty could be just an old wives’ tale, scientists claim.
It follows a study into “astronauts” on simulated flights to Mars.
Two groups of ten male volunteers were sealed into a mock spaceship.
A salty diet caused them to drink less, triggering a mechanism to conserve water in the kidneys.
The findings are from the German Aerospace Centre, Max Delbruck Centre for Molecular Medicine and Vanderbilt University in Tennessee.
Prof. Friedrich C. Luft, Managing Director of the Charité University Hospital, Berlin, said: “It’s not solely a waste product, as has been assumed.
“Instead, it turns out to be a very important osmolyte – a compound that binds to water and helps transport it.
“Its function is to keep water in when our bodies get rid of salt.
“Nature has apparently found a way to conserve water that would otherwise be carried away into the urine by salt.”
Before the study, scientists had believed that the charged sodium and chloride ions in salt grabbed onto water molecules and dragged them into the urine.
The new findings change the way scientists have thought about the process by which the body achieves water homeostasis – maintaining a proper amount and balance.
Prof. Jens Titze, MD of the University of Erlangen and Vanderbilt University Medical Centre, said: “We now have to see this process as a concerted activity of the liver, muscle and kidney.
“While we didn’t directly address blood pressure and other aspects of the cardiovascular system, it’s also clear that their functions are tightly connected to water homeostasis and energy metabolism.”