Most people consume far too much salt because it might put us in a better mood, according to a new discovery.
University of Iowa (U-I) psychologist Kim Johnson and colleagues found that when rats are deficient in salt, they shy away from activities they normally enjoy, like drinking a sugary substance or pressing a bar that stimulates a pleasant sensation in their brains.
"Things that normally would be pleasurable for rats didn't elicit the same degree of relish, which leads us to believe that a salt deficit and the craving associated with it can induce one of the key symptoms associated with depression," Johnson said.
U-I researchers can't say it is full-blown depression because several criteria factor into such a diagnosis, but a loss of pleasure in normally pleasing activities is one of the most important features of psychological depression.
And, the idea that salt is a natural mood-elevating substance could help explain why we're so tempted to over-ingest it, even though it's known to contribute to high blood pressure (BP), heart disease and other health problems.
Past research has shown that the worldwide average for salt intake per individual is about 10 grams per day, which is greater than US Food and Drug Administration recommended intake by about four grams, and may exceed what the body actually needs by more than more grams.
High levels of salt are contained in everything from pancakes to pasta these days, but once upon a time, it was hard to come by.
Salt consumption and its price skyrocketed around 2000 BC when it was discovered as a food preservative, said an U-I release.
Today, 77 percent of our salt intake comes from processed and restaurant foods, like frozen dinners and fast food.
These findings were published in Physiology & Behaviour.