Let’s get dirty. I promise you’ll feel better afterwards, or at least science does!
Your Dirty Mind
You may remember that taking a nature bath can boost your health and promote feelings of well-being. It turns out that getting really up close and personal with nature can also help. Soil is full of germs, right? We warn our kids about it and try to keep them away from mud. Maybe we should stop.
One particular type of bacterium that lives in soil is Mycobacterium vaccae. Exposure to M. vaccae has been shown to boost serotonin levels. This is good news as it could be used to treat depression. It could also boost our learning ability.
I love nature, I just don’t want to get any of it on me.” – Woody Allen
Researchers have been using m. vaccae in vaccines to test treatments for a host of diseases including cancer, tuberculosis and skin conditions. When some cancer patients reported an uplift in their mood, researchers at Bristol University and University College London wondered if it was due to the dead bacteria in the vaccine. So they decided to find out.
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They injected mice with dead m. vaccae cells. This led to neurons in the mice brains producing more serotonin. As depression and anxiety in humans have been linked to reduced levels of serotonin, boosting serotonin levels naturally may help to alleviate these conditions.
“[These studies] leave us wondering if we shouldn’t all be spending more time playing in the dirt.” – Dr Chris Lowry, lead author
Serotonin also plays an important role in learning. Researchers Dorothy Matthews and Susan Jenks wondered if m. vaccae would stimulate an improvement in learning like it did with mood. To test this they fed live bacteria to mice and observed them learning their way around a maze.
“Mycobacterium vaccae is a natural soil bacterium which people likely ingest or breath in when they spend time in nature,” – Dorothy Matthews, lead author
The mice that were fed the m. vaccae bacteria were able to navigate the maze twice as fast as mice that were not. And they showed fewer signs of anxiety to boot.
Life in the developed world is increasingly sanitized. We don’t even need to touch our dispensers to get a dose of anti-bacterial soap! Everything is clean, clean, clean. And some scientists wonder if this is behind the rise in asthma and allergies in our kids.
Interestingly, kids raised on dairy farms have much lower rates of asthma and allergies. Some scientists think that these kids breathe in fragments of dead bacteria from manure and cow fodder. This triggers a low-level immune response that protects them from developing asthma and allergies in later life. A Swedish study found that exposure to farm animals and household dogs during a child’s first year reduces the risk of developing asthma by age six.
This is what is known as the Hygiene Hypothesis. Simply put, we may be too clean. Our immune systems may not learn to distinguish harmful pathogens from harmless allergens. This can trigger immune responses to dust or grass pollens or even to cells in our own bodies. If we get dirty we train our immune system to better identify potential threats.
While the jury is still out on the hygiene hypothesis, the evidence is mounting.
Getting Dirty Is Good For The Elderly
Gardening is good exercise. It is a gentle form of natural movement that keeps you active, gets you outside in the sun and the dirt and connects you with nature. Even better, you can use this form of exercise to grow healthy food as well.
Gardening is exactly the type of exercise that long-lived people regularly engage in. Okinawa island in Japan holds the record for the most centenarians in the world. On top of that, people in their eighties and nineties act like they are thirty years younger.
Exercise is vital for longevity, but the Okinawans do not hit the gym. Instead they incorporate dancing, gardening, walking and gentle exercise like tai chi into their daily routines.
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So getting dirty is good for you. It’s the smart thing to do. It may give your immune system a kick, it can make you smarter and happy and if you work up a little sweat, it can also help you live longer.
So go dig out a mud-pool and get dirty! Or plant a vegetable garden. Or run or bike on dirt tracks.
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University Of Bristol – Getting Dirty May Lift Your Mood
EurekAlert – Can bacteria make you smarter?
Pubmed -Ingestion of Mycobacterium vaccae decreases anxiety-related behavior and improves learning in mice.
Wikipedia – Mycobacterium Vaccae
Science Direct -Identification of an immune-responsive mesolimbocortical serotonergic system: Potential role in regulation of emotional behavior
Jama Pediatrics –Early Exposure to Dogs and Farm Animals and the Risk of Childhood Asthma
WebMd – Is Dirt Good For Kids?
NCBI -Secret of Eternal Youth; Teaching from the Centenarian Hot Spots (“Blue Zones”)