http://www.medicalnewstoday.com/articles/66840.php
UK scientists suggest that a type of friendly bacteria found in soil
may affect the brain in a similar way to antidepressants.Their findings are published in the early online edition of the
journal Neuroscience.Researchers from Bristol University and University College London
discovered using laboratory mice, that a “friendly” bacteria commonly
found in soil activated brain cells to produce the brain chemical
serotonin and altered the mice’s behaviour in a similar way to
antidepressants.
A whole literature exists on the importance of connection to nature for human well being. Harvard Biologist E.O. Wilson coined the term Biophilia, for example, and if you follow through with some links to the research it is clear that this recent article is just one more piece of evidence in a fascinating line of inquiry. I don’t recall anybody identifying a particular biochemical pathway, however, so this may really be something new.
From personal experience as a farmer, I can attest to feeling pretty good after a healthy day with the dirt. But I always assumed it was the sunshine.