Researchers recently started out an experiment trying to show that boosting serotonin via dietary manipulation would help mood. Much to their surprise they ended up wondering if excess sugar intake is the main driving force behind depression in America.

Serotonin is an important brain neurotransmitter that needs to be kept in balance with other neurotransmitters for optimal brain function and mood. It is often targeted with anti-depressant drugs with the goal of boosting up its levels. Sometimes that helps and other times horrid side effects can occur, including suicide and violent behavior outbursts.

In the new study, scientists used a diet high in sugar¹ and tryptophan to rapidly boost serotonin levels. The amino acid tryptophan, which makes serotonin, competes with other amino acids like phenylalanine and tyrosine for entry into your brain. By feeding sugar, insulin is raised which stimulates muscle uptake of these other amino acids allowing tryptophan to enter the brain without the typical competition. This was expected to improve the abnormal mental behavior in the mice population that was being studied. Much to the surprise of the researchers, it made their behavior much worse. In fact, a second experiment found that mice with no mental health problems began to develop them after being on the diet.

This form of dietary manipulation is carried out by humans on a regular basis when they eat too much sugar. Perhaps we have a solution for a large part of the 10% of Americans on anti-depressants.