Bacteria, found in dirt, with antidepressant qualities, and with the added bonus of improving the ability to learn. Bacteria that make you feel good and make you smarter too. What a concept.

But think about it. When you go out in nature, and breathe deeply, don't you feel refreshed? Renewed? Possibly invigorated? Even if you were in a negative frame of mind before going out.

Well, out in nature is where you'll probably encounter Mycobacterium vaccae. The bacterium M. vaccae is found in the soil, and Dorothy Matthews of the Sage Colleges in Troy, New York, says we inhale it or ingest it when we're out in nature.

Research on mice indicates that mice who were fed live M. vaccae were sharper than mice who were not fed the bacterium M. vaccae.

"This research suggests that M. vaccae may play a role in anxiety and learning in mammals," says Matthews. "It is interesting to speculate that creating learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks."

http://www.sciencedaily.com/releases/2010/05/100524143416.htm