A team of international researchers has found that salt may cause people to drink less water and become more hungry, a new study published in the Journal of Clinical Investigation reports.
Conventional scientific wisdom says that salt makes a person thirsty. However, the findings outlined in the new research suggest just the opposite.
In the study, the team checked salt’s effect on the body during simulated missions to Mars. They found that “cosmonauts” who ate more salt were not as thirsty as those who ate less. Rather, they needed more energy, which caused them to be hungry.
Researchers also looked at two groups of 10 male volunteers that were sealed into a mock spaceship for two simulated flights. They examined the first group for 105 days and the second for 205. Though all of the subjects had identical diets, they were given three different salt levels in their food over a period of several weeks.
The data showed that eating high levels of salt caused people to urinate more frequently. However, this rise was not the result of increased liquid intake. In fact, the researchers found that the participants tended to drink less. Rather, salt triggered a mechanism to conserve water in the kidneys.
“This water-conserving mechanism of dietary salt excretion relies on urea transporter-driven urea recycling by the kidneys and on urea production by the liver and skeletal muscle,” the researchers noted in the study, according to Yahoo News.
Conserving the body’s water may be important during a long space flight through the cosmos. Even if the study does not directly help space travel, it could still have important applications in other fields.
Prior to the study, scientists believed that the sodium and chloride ions in salt latched onto water molecules and dragged them into the urine. These new results show that salt stays in the urine, leaving water to move back into the body. This finding could change the way scientists view that process and may lead to new research about the way that the substance affects the body.
“We have always focused on the role of salt in arterial hypertension. Our findings suggest that there is much more to know — a high salt intake may predispose to metabolic syndrome,” said study co-author Jens Titze, associate professor of Medicine and of Molecular Physiology and Biophysics, in a statement.