Is mud the key to a happy life?

Dirt – perhaps not the first thing you might think of as the ideal treatment for depression. However, scientists have found that mud could indeed be an elixir of mood.

Researchers at the University of Bristol and University College London found that treatment of mice with ‘friendly’ bacteria, normally found in the soil, altered their behavior in a way similar to that produced by antidepressant drugs.

The findings could aid the understanding of why an imbalance in the immune system leaves some individuals vulnerable to mood disorders.

Dr Chris Lowry, lead researcher on the team from Bristol University, said: “These studies help us understand how the body communicates with the brain and why a healthy immune system is important for maintaining mental health. They also leave us wondering if we shouldn’t all be spending more time playing in the dirt.”
When the team looked closely at the brains of the mice, they found that treatment with Mycobacterium vaccae activated a group of neurons that produce the brain chemical serotonin.

The fact that the lack of serotonin in the brain is thought to cause depression in people, plus anecdotal evidence that cancer patients treated with M.vaccae had reported improvements in their quality of life, led the team to conclude that the effect may be due to increasing the release of serotonin in parts of the brain that regulate mood.

The work, published in the journal Neuroscience is not the only research to suggest a link between serotonin and immunity. A team at Georgetown University Medical Center in Canada recently discovered serotonin is passed between key cells in the immune system, and that the chemical can activate an immune response.

However, the relationship is a complex one. There is the suggestion that serotonin may boost the immune system to the point where it could trigger autoimmune diseases.