Germs and smarts

I missed this story when it came out in May, but I heard it being discussed on the radio today.

In mice at least, eating a common soil bacteria seems to make them learn faster.  From the Science Daily report:

"Mycobacterium vaccae is a natural soil bacterium which people likely ingest or breath in when they spend time in nature," says Dorothy Matthews of The Sage Colleges in Troy, New York, who conducted the research with her colleague Susan Jenks.

Previous research studies on M. vaccae showed that heat-killed bacteria injected into mice stimulated growth of some neurons in the brain that resulted in increased levels of serotonin and decreased anxiety.

"Since serotonin plays a role in learning we wondered if live M. vaccae could improve learning in mice," says Matthews.

Matthews and Jenks fed live bacteria to mice and assessed their ability to navigate a maze compared to control mice that were not fed the bacteria.

"We found that mice that were fed live M. vaccae navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice," says Matthews.

In the radio interview today, the researcher said they really have no idea whether the same thing happens in humans.  But all the same, it's an intriguing idea that being too hygienic may not only be bad for allergies, but might make learning slower too.