I’m always in a good mood after working in the garden. Maybe it’s the combination of exercise, fresh air, sunshine, and…Mycobacterium vaccae? A common, harmless bacteria found in soil, M. vaccae thrives best in soil with rich organic content. Studies by neuroscientist Christopher Lowry, which were inspired by oncologist Mary O’Brien, have revealed that this bacteria may literally make you happy by increasing serotonin levels.
But this bacteria also increases resistance to inflammation. This ties into Dr. Erika von Mutius’ “hygiene hypothesis,” which developed from her study of children living in two contrasting environments of East and West Germany. Basically, the children exposed to more microbes developed less problems with asthma and allergies.
These recent findings reflect the overarching philosophy about soil and human health put forth by Dr. Royal Lee, Sir Robert McCarrison, Sir Albert Howard, and many others in the ’40s and ’50s. Although they didn’t identify the exact microbes in dirt that have positive effects on human health, they knew there was a connection between the health of soil and the health of humans. A fundamental principle of nutrition espoused by McCarrison and Howard is that the nutritive value of natural foods depends on the health of the soil it is grown in. “In the course of this work it was soon discovered that the thing that matters most in soil management is a regular supply of freshly made humus, prepared from animal and vegetable wastes, and that the maintenance of soil fertility is the real basis of health.” Read more of their theories on nutrition and soil fertility here.