Heroes Not Zombies

It’s becoming increasingly clear that bacteria and human beings interact in profound and complex ways. I wrote recently about the way bacteria in our guts might affect our food choices and behaviour. Well, here’s an interesting study looking at the antidepressant effect of mycobacteria vaccae which are found in the soil.

Antidepressant microbes in soil cause cytokine levels to rise, which results in the production of higher levels of serotonin. The bacterium was tested both by injection and ingestion on rats and the results were increased cognitive ability, lower stress and better concentration to tasks than a control group. Gardeners inhale the bacteria, have topical contact with it and get it into their bloodstreams when there is a cut or other pathway for infection. The natural effects of the soil bacteria antidepressant can be felt for up to 3 weeks if the experiments with rats are any indication.