New Study Overturns Beliefs About How Salt Affects Thirst, Heart Disease And Obesity

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It is typically thought that eating foods with a high amount of salt could lead to increased thirst. ^[1] This bartender notion may be true in the short term, but over a longer period, a high-salt diet actually diminishes thirst while increasing hunger, according to two papers reported in the Journal of Clinical Investigation. ^[2]

The two studies involved a team of researchers from German Aerospace Center, the Max Delbrück Center for Molecular Medicine (MDC), and Vanderbilt University. For the first study, which was carried out between 2009 and 2011, they used Russian cosmonauts who were part of a human space flight simulation program. The subjects were required to collect and measure every crumb and every urine drop during a 105-day and 520-day stretches of a hermetically-sealed simulation spaceflight.

Health authorities have always suggested that a diet high in salt is typically associated with an increase in liquid intake. What the researchers observed have upended more than a century of conventional scientific wisdom on the body’s response to high salt consumption. Their findings are outlined below:

• The cosmonauts drank less water as their salt intake went up.

• The subjects also peed more and had more sodium in their urine.

• The urine of the subjects was more concentrated, which means their body was holding onto more water.

The researchers conducted a subsequent study in mice to understand the surprising results they derived from the human study. They gained more information on the effect of high salt intake into the body:

• More salt leads to a state driven by glucocorticoids, which breaks down protein and converts it to urea.

• Urea prevents body water loss while the salt is excreted from the body.

• The body “cannibalizes” itself to produce more water, a process that makes a person hungry.

• Increased levels of glucocorticoids are a risk factor for obesity, diabetes, and cardiovascular disease. ^[3][4][5]

According to the studies of senior author Dr. Jens Titze of Vanderbilt University, their investigation presented evidence on why people need to radically reduce their salt consumption. The U.S. Centers for Disease Control and Prevention’s Sodium and Dietary Guidelines recommend Americans to consume less than 2,300 milligrams of sodium per day. ^[6] Americans’ penchant for processed foods and restaurant meals is exposing them to higher sodium intake. ^[7]

Dr. Titze believes that their findings might offer a new page into the epidemics of obesity, diabetes, and heart disease. She stresses that their trials offered a new dynamic on how reduced sodium diets could influence the three diseases in unexpected ways. ^[8]

The two studies also revised the scientific community’s view of the function of urea in our bodies. Titze and colleagues presented urea as not merely a waste product but as a very important compound that binds water and helps transport it.