Dirt exposure 'boosts happiness'
Exposure to dirt may be a way to lift mood as well as boost
the immune system, UK scientists say.
Lung cancer patients treated with "friendly" bacteria normally
found in the soil have anecdotally reported improvements in their
quality of life.
Mice exposed to the same bacteria made more of the brain's "happy"
chemical serotonin, the Bristol University authors told the journal
Neuroscience.
Common antidepressants work by boosting this brain chemical.
Dirty play
A lack of serotonin is linked with depression in people.
The scientists say more work is now needed to determine if the
bacterium Mycobacterium vaccae has antidepressant properties
through activation of serotonin neurons.
Lead researcher Dr Chris Lowry 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 spend more time
playing in the dirt."
The work could also help experts' understanding of why an imbalance
in the immune system leaves some individuals vulnerable to mood
disorders like depression, he added.
Mood and immunity
Canadian researchers have also been exploring the links between
serotonin, mood and immunity.
A team at Georgetown University Medical Center recently discovered
serotonin is passed between key cells in the immune system, and
that the chemical can activate an immune response.
This suggests that serotonin may restore a healthy immune function
in people who are depressed and prone to infections.
On the flip side, it is also possible that serotonin, and
serotonin-boosting antidepressants, end up bolstering immunity to
the point that they trigger autoimmune disease where the body
attacks itself.
Gerard Ahern, lead researcher on the study, explained: "At this
point we just don't know how these drugs might affect immunity, so
we really need to clarify the normal role of serotonin in immune
cell functioning."
Happy as a pig...