Interestingly enough, Caltech just released a study last month that shows that gut microbes directly help produce serotonin in the gut: http://www.caltech.edu/

Interestingly enough, Caltech just released a study last month that shows that gut microbes directly help produce serotonin in the gut: http://www.caltech.edu/news/microbes-help-produce-serotonin-gut-46495 http://www.caltech.edu/news/microbes-help-produce-serotonin-...