Most Americans eat too much salt, and a new study may explain why we grab a bag of chips when we feel blue — salt may be a natural antidepressant.
University of Iowa researchers found that when rats were deficient in sodium chloride, common table salt, they didn’t participate in activities they had previously found pleasurable, such as pressing a bar that stimulated a pleasure center 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,” said UI psychologist Kim Johnson.
The theory that salt creates a natural “high” could help explain why we eat so much of it, even when we know it is associated with health problems, including high blood pressure and heart disease.
Average daily salt intake worldwide is about 10 grams a day, six grams greater than the U.S. Food and Drug Administration recommendation, and as much as eight grams above the amount the body actually needs.
Experts believe evolution may play a part in our love of salt. Early creatures lived in salty oceans, but after man moved inland and away from easy access to salt, his body still needed it to help fluids pass in and out of cells and to help nerves transfer information.
“Most of our biological systems require sodium to function properly, but as a species that didn’t have ready access to it, our kidneys evolved to become salt misers,” Johnson said. Human beings, like other animals, have an innate system that remembers the location of salt sources, and a pleasure mechanism is activated when salt is eaten.
Now scientists are finding that salt is an addictive substance that is abused almost like a drug. Those who eat too much salt do so knowing it is harmful to their bodies — a hallmark of addiction. Another aspect of addiction, cravings when drugs are withheld, also applies to animals that become deficient in salt. Experiments have shown the same areas of the brain are involved.
“This suggests that salt need and cravings may be liked to the same brain pathways as those related to drug addiction and abuse,” Johnson said.
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