Dirt may ease depression


A study carried out at Bristol University and University College London has found that a common, friendly soil bacterium can produce the same uplifting effects as anti-depressant drugs.

The bacterium - Mycobacterium vaccae - appears to work by stimulating the body’s immune system. This, in turn, prompts the brain to produce seratonin - a hormone associated with feelings of wellbeing.

Interest in this idea was piqued when cancer patients being treated with M vaccae unexpectedly experienced an increased quality of life.
There were already a number of studies supporting the hygiene
hypothesis - the idea that exposure to microbes is beneficial to health - and a growing body of research showing the importance of the immune system in regulating even the subtlest aspects of health.

The new study extends the existing research by increasing understanding about how the body and brain communicate with each other, and why a healthy immune system is important for maintaining mental, as well as physical health.

The question now is how to get the bacteria into people's systems, and the scientists involved in this latest study are working with a pharmaceutical company to look at whether M vaccae could become the basis of new treatments for conditions such as asthma and allergies, as well as depression.

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First Published in July 2007

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