A group of German and U.S. scientists found that salt stimulates appetite and has no influence on our thirst. The findings could help researchers develop new therapies for chronic illnesses and conditions such as heart disease, type 2 diabetes, and obesity.
The study appeared this week in the Journal of Clinical Investigations.
Study authors found that contrary to the common belief, salt does not drive out water through urine, thus reducing water content in our bodies. Instead, salt conserves water and helps with water production.
Researchers at the Germany-based Max Delbrück Center for Molecular Medicine found that the theory that sodium ions attracts water molecules and pushes them out of the body through urine is wrong. In fact, salt does the opposite: the body urinates less, which doesn’t stimulate our thirst.
The recent research revealed that while salt stayed in the urine, the water returned into the kidneys, and from there into the body.
The experiment is part of a larger series of trials designed to help humans survive Mars’ conditions. In the latest trial, two teams of male volunteers with identical diets were given different amounts of salt.
Researchers found that a salty diet paradoxically made volunteers drink less water. They found that excess salt prompts kidneys to conserve water and release extra urea. The process is very energy-consuming so subjects became more hungry not thirsty.
The ‘astronauts’ who had salt-rich diets experienced water retention, weren’t thirsty, and were hungrier than their peers as they needed more energy to metabolize salt.
Researchers said that their discovery challenges previous theories about the way the human body reaches water homeostasis, or maintains a proper amount of water. The team found that the liver, muscles, and kidneys were equally important in achieving the right water balance.