Is Salt Nature's Antidepressant?

Helen Fields
for National Geographic News
March 17, 2009

Could salt be the solution to a sad, empty life?

Maybe, says physiologist Alan Johnson of the University of Iowa.

He's found that sodium-deprived rats take less pleasure in daily activities—they can't be bothered to drag themselves across the cage to push a bar that releases a dose of sugar water.

But let the rats have salt again and "they're all happy," Johnson said.

Very low sodium in rats, humans, and other land animals may induce something similar to depression—and that eating more salt may make us happier, Johnson thinks.

He points to one study of people with chronic fatigue syndrome. Many of the patients were found to have reduced their sodium intake for health reasons. Increasing sodium in their diets alleviated many of the patients' symptoms.

No Excuse for a Salt Binge

Land animals have to work constantly to keep their cells bathed in a nice salty solution like the sea our distant ancestors lived in. Our kidneys are beautifully adapted to this task—adjusting the concentration of urine based on how salty the blood is.

But most modern humans eat way more salt than they need.

The brain may continue being happy about salt even when it doesn't strictly need it, in the same way the brain may "reward" us when we eat too much or take dangerous drugs, Johnson said.

So don't start eating sodium-filled frozen dinners to cheer yourself up. The connection between salt and mood is just starting to be fleshed out, but scientists are certain about the link between salt and heart disease.

Findings detailed in the journal Physiology and Behavior.

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