Depression and Salt

A new study from the University of Iowa found that salt is a good conductor and probably affects our brain function. According to the study, when deprived of salt rats were far less inclined to participate in activities they typically enjoyed—like pressing a bar that stimulated pleasant sensations 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,” Kim Johnson, the study designer, said. “A loss of pleasure in normally pleasing activities is one of the most important features of psychological depression.”

Mrs. Johnson reviewed other salt research as well. Long before the first refrigerator rolled off the assembly line salt was considered the best food preservative. And, it was expensive. Roman soldiers were paid in salt; the word salary is derived from the Latin word for salt. Long before the first refrigerator rolled of an assembly line salt was a coveted commodity. Today, salt is everywhere. 77 percent of our salt intake comes from processed and restaurant foods. There are 260 mgs of salt in one pickle! 135 mgs in the average slice of bread. Even bladder healthy cranberry juice has about 35 mgs of sodium per cup. It isn’t there naturally but added my many manufacturers, perhaps for taste. A slice of bacon contains 1021 mgs of salt. Canadian bacon 2500! There is your daily intake right there.

The idea of salt as a  mood-elevating substance might help explain why we are so tempted to over-eat it. The average salt intake per individual is recommended to be about 4 grams per day. The average person takes in approximately 10 grams per day. This may exceed what the body actually needs by more than 8 grams. New U.S. dietary guidelines now recommend that people aged 2 and older limit daily sodium intake to less than 2,300 milligrams (mg). People aged 51 and older, blacks and anyone with high blood pressure, diabetes or chronic kidney disease should consider going down to 1,500 mg per day, many experts say. The American Heart Association believes the 1,500-milligram-a-day recommendation should apply to all Americans.

One theory is that evolution is part of our craving for salt—that we evolved from creatures in the salty seas. And, once on land, our body continued to need sodium and chloride because those minerals play key roles in allowing fluids to pass in and out of cells; and in helping nerve cells transfer information throughout the brain and body. But as man evolved in the hot climate of Africa, perspiration robbed the body of sodium. Salt was scarce because our early ancestors ate a veggie-rich diet and lived far from the ocean. “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.

A pleasure mechanism in the brain is activated when salt is consumed.

Behavior also came to play a key role in making sure we have enough salt. All animals—and humans—are born with a taste system designed to not only detect salt but remember where we located it. Think of salt licks placed strategically in cow and horse pastures. Perhaps because of salts ubiquity we have lost all of our sense of conserving it. There is ample evidence that salt is as abused and addictive a substance as sugar, alcohol or any other drug. A sign of addiction is using a substance that we know is harmful. That said, people are constantly being told to mitigate their salt intake, mostly to no avail. People just can’t seem to do that. Another aspect of addiction is intense cravings when drugs are withheld.

The good news is that the tongue grows a new set of taste buds every three weeks. If one wanted to recalibrate their taste buds to not crave salt, all he would have to do is do without it for a few weeks.

Mood elevation that’s tied to salt consumption could be caused by the salt, but it also could be the other way around. Maybe the lack of salt causes anxiety, which is alleviated by eating salt and giving the body what it wants. The study was published in the July issue of the journal Physiology & Behavior with Michael J. Morris and Elisa S. Na, UI graduate students.