Probiotic Bacteria Alter Brain Chemistry, Behavior; What Are the Broader Implications?

Ted Schettler, MD, MPH
Science Director

An article in ScienceDaily titled “Mind-Altering Microbes: Probiotic Bacteria May Lessen Anxiety and Depression” begins with this lead:

Probiotic bacteria have the potential to alter brain neurochemistry and treat anxiety and depression-related disorders according to research published in the Proceedings of the National Academy of Sciences.
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The journal reference is Javier A. Bravo, Paul Forsythe, Marianne V. Chew, Emily Escaravage, Hélène M. Savignac, Timothy G. Dinan, John Bienenstock, John F. Cryan. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1102999108. (visit the abstract)

This study in adult male mice shows alteration of GABA mRNA levels in the brain, reduced corticosterone levels, and behavioral changes associated with Lactobacillus treatment, mediated via the vagus nerve. The direction of changes in GABA levels varied in different brain regions. The authors are mainly concerned with measures of anxiety- and depression-related behavior.
 
But it strikes me that these findings may have broader implications.