Saturday, September 18, 2010

Garden Tranquilizers

If, my fellow gardeners, you missed the news while you were out digging and planting, Science has recently discovered that gardening is addicting, or at least responsible for our generally cheerful moods, and even better, that gardening might make us smarter.

Stupid scientists.  We already knew both those things, didn't we?

It's all about a natural soil bacterium called Mycobacterium vaccae.  Previous research studies have shown that heat-killed M. vaccae injected into mice stimulated growth of some brain neurons that resulted in increased levels of serotonin and decreased anxiety.  Serotonin, for the medically uninitiated, is a neurotransmitter that helps us sleep, regulates our body clocks and our body temperature, and regulates our daily cycle of endogenous cortisol, calming us down at night. So, in essence, due to bacteria we're exposed to as we dig, gardening is just a big dose of anti-depressants for its stalwart devotees. It's also true that LSD acts through stimulation of serotonin receptors, so draw your own conclusions from there to some of the gardeners you know.

More recently, a study presented in San Diego by Dorothy Matthews and Susan Jenks at the 110th General Meeting of the American Society for Microbiology reported on the ability of mice to navigate a maze after being fed the bacteria..  The result;  M. vaccae-fed mice negotiated the maze twice as fast and with less demonstrated anxiety behaviors than control mice.

As gardeners, we're constantly exposed to M. vaccae through breathing or ingestion (for those who garden with an open mouth), so, in theory, every time we dig into the dirt, we relax a little bit and we get a little smarter.   I, for one, am happy to keep digging (or I'm digging to keep happy)  to get my daily fix of M. vaccae.  I'll leave it to the WEEW/OGB (Wild-Eyed Environmental Wackos/Organic Nut-Balls) to promote eating dirt clods or drinking muddy water for the "natural" benefits.

Follow-up experiments by Matthews and Jenks showed that the increased intelligence effect was temporary (diminished after several weeks)  if the exposure to M. vaccae was withdrawn, suggesting that it is important for us to keep digging regularly and perhaps explaining why Northern Hemisphere gardeners are so depressed during winter months.  Rebecca Kolls of Rebecca's Garden TV show fame was always telling us to "Keep those hands dirty!" wasn't she?   If nothing else, we now have some evidence why gardeners should be better at getting around those corn mazes that crop up everywhere in the Fall.

1 comment:

  1. Hi Dr James, Thank you for sharing this finding. That explains the joy I feel in digging. I need to go look for some M. vaccae now.


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