Did You Know… bacteria in dirt make us happier, and may even help fight depression, cancer, and other diseases?
Nature nurtures—it’s a fact. Many studies confirm that being outside in nature and connecting with the earth is therapeutic, and recent research explains why.
It seems a strain of bacterium called Mycobacterium vaccae (M. vaccae) found in soil stimulates your body’s production of serotonin, a feel-good hormone that helps improve mood and calm anxiety. M. vaccae may even help to boost brain function and treat cancer and other diseases!
Not All Bacteria Is Bad
M. vaccae (pronounced “emm vah-kay”) took the spotlight thanks to oncologist Mary O’Brien of Royal Marsden Hospital in London. O’Brien discovered that inoculating lung cancer patients with the bacterium not only alleviated some of their cancer symptoms, but also helped improve their vitality, emotional health, and cognitive function.
Dr. Chris Lowry of Bristol University expanded on O’Brien’s research by connecting M. vaccae to an increase in serotonin production. He injected mice with M. vaccae and tested their cytokine levels. Cytokine is part of a chain reaction that produces serotonin. As theorized, the mice injected with the bacterium had higher cytokine levels and exhibited less stress than mice in the control group.
Researchers at Sage Colleges in Troy, New York fed mice the bacterium and tested them in a maze against mice not fed the bacterium. The M. vaccae mice performed twice as fast and with half the anxiety of the mice in the control group. Past research has shown that serotonin helps to improve concentration and cognitive function. Once off the bacterium diet, the mice continued to perform better than the control mice up to week 3, when performance levels between the 2 groups became more matched and were no longer statistically different.
What does this mean for us humans? It’s too soon to tell, but Dorothy Matthews of Sage Colleges says this:
“From our study we can say that it is definitely good to be outdoors—it’s good to have contact with these organisms. It is interesting to speculate that creating learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks.”
The future health implications are promising. In the meantime, we don’t need to eat the bacterium or be injected. Just getting outside and gardening can offer benefit. Digging in the soil and inhaling the bacterium is just as restorative as the relaxing but gentle exercise gardening provides.
In fact, a recent study published in the New England Journal of Medicine reported that children who grow up on farms are 30-50% less likely to have asthma as other children. Researchers believe this is due to the diverse variety of bacteria and fungi from soil and farm animals that hang out in household dust. So don’t be afraid to get dirty!