All the gardeners I know, including myself, feel better when we are working in the garden. Some people say it is a meditative experience – a way to separate yourself from the troubles of the everyday.
I love getting my hands into the soil. I rarely wear gloves because I like the feel of the soil.
Recent research has given some scientific basis for that good feeling we get in working the soil. Contained in soil is Mycobacterium vaccae, a nonpathogenic species of bacteria. It occurs naturally. Researchers have been studying how killed Mycobacterium vaccae vaccine might be used as immunotherapy for allergic asthma, cancer, leprosy, psoriasis, dermatitis, eczema, tuberculosis, Crohn’s disease, rheumatoid arthritis – and depression.
That last area of research is what brings me to happy soil. It has recently been hypothesized that exposure to Mycobacterium vaccae may result in an antidepressant effect, because it stimulates the generation of serotonin and norepinephrine in the brain. There may be some natural Prozac in that dirt.
Lack of serotonin is linked to depression, anxiety, obsessive compulsive disorder and bipolar problems. Many antidepressant drugs are ones that trigger the production of serotonin and norepinephrine in the brain.
Now, don’t go out in the backyard and start eating dirt. Working the soil means we make contact with the microbes through the skin and also by breathing some in as we stir up the soil.
The research shows that these microbes cause cytokine levels to rise and that results in the production of higher levels of serotonin. In the studies, the bacterium was tested both by injection and ingestion – but that was on rats. The natural antidepressant effect can be felt for up to 3 weeks.
Maybe those pigs and other animals rolling in the dirt were doing more than keeping cool and keeping off insects.