Get Germy Outside and Be Smarter and Happier


Researchers have been linking certain bacteria and beneficial health properties for years and now a new study has linked one type of germ with boosting mood and learning capabilities.

Researcher Dorothy Matthews of the Sage Colleges in Troy NY noted that previous research had found that mycobacterium vaccae, a type of natural bacteria found in soil, increased levels of serotonin in the brain when heat treated and injected into mice. Serotonin is a neurotransmitter that regulates mood. The mice that were given M.vaccae were less anxious than those untreated.

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Serotonin is also associated with learning, so Matthews and colleague Susan Jenks fed live M.vaccae bacteria to mice and put them through a maze to test their ability to learn to navigate. The mice that were given the bacteria “navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice,” Matthews said.


The effect is not long-lasting, however. Three weeks after stopping the bacterial ingestion, the mice showed a significant decline in abilities. Although they were still faster than the mice in the control group, they did not learn the maze as fast as when they were given the bacteria.

So how does this translate to humans? Spending time outdoors has been associated with improved mood and sense of well-being. Gardening in particular has been shown to lower stress levels. Matthews proposes that one of the reasons is that we breathe in these bacteria when we are outside around plants and trees or come in contact with it through the skin.

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She suggests that schools create learning environments outside so that students “may decrease anxiety and improve the ability to learn new tasks.” For adults, taking an “outdoor break” during the day can bring relaxation and possibly improve productivity at work by clearing the mind.

Read: Five Minutes of Green Exercise Can Improve Mental Health

The findings of this study were released at the 110th General Meeting of the American Society for Microbiology in San Diego.