NEW ORLEANS — If your teenager is down, a new study shows that you could get help from your local grocery store rather than a therapist's office.  

Researchers at the University of Alabama at Birmingham studied adolescents for a year, and found a connection between bad diets and depression. 

To understand the study, we turned to diet and exercise researcher Dr. Melinda Sothern of LSU Health Sciences Center. She explained that diets high in sodium (another word for salt), and low in potassium, can have a profound negative effect on the brain, specifically behavior and cognition. 

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To be specific, that means the part of the brain involved in decision making, impulse control, mood and happiness can see major changes depending on the diet it is fed. 

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So how did they know? All they had to do was check the amount of sodium and potassium in their urine. 

And where were these chemical coming from? Processed and junk food are high in sodium (which you don't want), and fruits, vegetables, and whole grains are high in potassium (which you do).  

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Researchers found the bad diet effect was worse in girls and that teens who carried too much weight were more likely to be depressed. 

So the fix can be simple. Pediatricians can get a urine test on children and a registered dietician can help show, once again, the benefit of eating whole foods from the earth rather than a box.