It has always intuitively made sense to me that spending time out in the garden is good for my health and general well being, especially for reducing stress. Well, it turns out that there may be a scientific basis for such a claim. A recent study on the effects of exposure to a common soil bacteria (mycobacterium vaccae) shows a strong correlation between the bacteria and improved learning and lowered anxiety.

Scientific American reports:

Studies have shown time spent in nature does us all good. Specifically a recent study done with 1,200 people, published in the journal Environmental Health and Technology found that even just five minutes in a leafy park can significantly boost our mood. Well it might be because we inhaled some bacteria among the leaves and grass...

Injecting this bacteria into mice has already been shown to increase serotonin levels and decrease anxiety. But the researchers wondered if it might have a subsequent effect on learning. They fed the bacteria to mice and then tested them in a maze.

And lo and behold these mice navigated the maze twice as fast as mice who received no bacteria.

The Montreal Gazette adds;

Matthews doesn't know how well the bacterium aerosolizes, "but certainly if you're vigorously working in the soil, there are probably some particles that are becoming airborne, so we may very well be inhaling it, as well as eating it by inhaling it and having it get into our GI (gastrointestinal) tract." We're also exposed via contact with food, especially foods grown directly in the soil, such as carrots and lettuce "and other things that are close to the soil..."

This may be an important data point for those advocating for gardening as part of school curriculum.

An interesting follow up to this would be to study the effects of Round Up and other ubiquitous weed killers on the presence of the bacteria. Organic gardeners have long been saying that soil is a complex community of life and we can't kill weeds and bugs with chemicals and not recognize that we are likely killing all kinds of other important forms of life. In the end, this effects the foods that we eat. It's not just the presence of pesticides and herbicides in our carrots that should concern us, but also the lack of important bacteria that are keys to human health.

To all my organic gardening friends, you officially have permission to say "I told you so."

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