Step away from the salt shaker.
Rather than make you grab a water bottle, researchers now say salty foods are making you hungry, not thirsty. According to a new study from the Max Delbrûck Center for Molecular Medicine in Germany and Vanderbilt University, salt triggers a process in the kidneys that retains water and requires energy that in turn makes you hungry.
The study, which involved two simulated missions to Mars, saw ten volunteers sealed in a spaceship for 105 days and 205 days. During the observation period, the volunteers were provided food with three different levels of salt content (6, 9 and 12 grams).
The researchers noted that the volunteers who started by consuming 6 grams of salt and increased to 12 grams drank less while their kidneys conserved more water. They also noticed consuming more salt led to a higher salt content in urine and a larger volume of urine altogether despite the volunteers not drinking more.
Prior to this study, researchers believed water was pulled out of the body by salt during urination, however, the new study finds the salt is expelled while water is recycled back into the body.
"Nature has apparently found a way to conserve water that would otherwise be carried away into the urine by salt," Professor Friedrich C. Luft, co-author of the study, said.
Still, the kidneys are only one area to consider. Professor Jens Titze of the University of Erlangen-Nürnberg says blood pressure and the cardiovascular system must be examined as their functions are also connected to water homeostasis and energy metabolism.
It's important to note that the new findings shouldn't be taken as an excuse to indulge in more salty snacks — the World Health Organization recommends adults consume no more than 5 grams of salt per day as high sodium consumption can contribute to high blood pressure, heart disease and stroke.