Friday, June 24, 2011

Bacteria Found in Soil Shown to Decrease Anxiety and Improve Learning Capabilities

Many people take pleasure in spending time outdoors, whether it be hiking, biking, gardening, or simply enjoying a day at the park. Not only do these outside activities provide an opportunity for fresh air, sunshine, and fun, but studies have shown that spending time outdoors and having contact with the soil can decrease anxiety and possibly improve learning capabilities.

Myobacterium vaccae is a species of bacteria that is a part of the mycobacterium genus. These cells are straight or slightly curved rods, and they are usually considered Gram positive. M. vaccae is a nonpathogenic bacterium that naturally lives in the soil. Immunotherapy for allergic asthma, cancer, depression, leprosy, psoriasis, dermatitis, eczema, and tuberculosis are all areas of research that have been pursued regarding a M. vaccae vaccine.

Research has shown that M. vaccae stimulates the generation of serotonin and norepinephrine in the brain. According to past studies linked to these findings, scientists have concluded that M. vaccae shows a decrease in anxiety. In addition, a more recent study proposed that neuron growth was stimulated when heat-killed M. vaccae was injected into mice.

Dorothy Matthews and Susan Jenks of The Sage Colleges in Troy, New York conducted some research. Matthews expressed that individuals are likely to breathe in the natural soil bacterium, Myobacterium vaccae, while spending time outdoors. She also stated, “Since serotonin plays a role in learning, we wondered if live M. vaccae could improve learning in mice.” This curiosity led Matthews and Jenks to conduct an experiment that involved feeding live bacteria to mice and then assessing their ability to navigate a maze. After performing the experiment, they concluded that the mice that were fed the live M. vaccae did, in fact, navigate the maze twice as fast and with less anxiety as the control mice that were not fed the live bacterium. Matthews and Jenks then performed two subsequent experiments that involved withholding the bacterium from the M. vaccae fed mice. The scientists found that the mice still navigated the maze slightly faster than the control mice. However, the effect did not last long, which meant that the effect was a direct result of the presence of the bacterium. Matthews said that this research proposes that M. vaccae may be linked to learning in mammals. She stated that “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.”

If Myobacterium vaccae does, in fact, have the same effects on humans, it would be necessary to spend time outdoors on a regular basis in order to stay in contact with the bacterium. Nonetheless, the information and conclusions gathered from these studies give even more reason to enjoy the great outdoors.


American Society for Microbiology. "Can bacteria make you smarter?." ScienceDaily, 25 May 2010. Web. 24 Jun. 2011.

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