Getting a little dirty can keep us healthy

Aborder between Finland and Russia is shedding light on how the environment might be affecting immune health. And lessons there are useful for those of us in the rest of the world, including New Mexico.

By studying people living on both sides of the border, researchers are learning more about why allergies and inflammatory diseases are increasing in developing nations around the world. Here’s what happened. During World War II, Finland turned over territory to the Soviet Union. In the years since, the Finnish side became more developed. People living on the Soviet side of the border continued living more traditionally.

By the 21st century, allergies on Finland’s side were significantly higher than those of the people who lived on the Russian side, according to a report in The Scientist Magazine in January.

Researchers swooped down in 2011 to try and find out why, suspecting that exposure to environmental microbes might account for the difference.

Finnish researchers already had developed the biodiversity hypothesis. This argues that total biodiversity — including diversity at microbial levels — of people’s living environments influences human health through changes to the microbiome, the genetic material of all the microbes living on and inside the human body.

If diversity across the globe is decreased, the human immune system will suffer. That loss of biodiversity, researchers believed, might be able to explain the increase in allergic and inflammatory diseases observed in developed nations around the world. The informative article was sent around locally by Carlos F. Valdez, with the Los Alamos Cooperative Extension Agent, to connections on Google. That makes sense, considering that as someone who works with 4-H and horticulture, Valdez is curious about biodiversity and all its implications.

According to the piece, researchers had tested skin swabs and found that children living in the country had more bacteria on their skin that city kids; the rural kids also were much less allergic.

What followed, researchers though, is that having more bacteria helped somehow boost the immune system. Now, the question was, how to develop an experiment that would either prove or disprove this notion.

The focus was on soil microbes — children living in the country are in contact with more dirt than children living amid pavement — which led researchers to attempt an experiment using mice. A group of female mice lived on clean bedding while other mice lived in cages where the bedding was sprinkled with potting soil and placed in a stable with other animals.

The clean mice were the losers, proving more susceptible to developing inflammation when an asthma-triggering allergen was introduced. Mice with soil around them, on the other hand, had more bacteria in their guts, the kind that protects from asthma and inflammation in both mice and humans.

All of that goes to show that a sterile environment is not the boon many have believed it to be, including moms who insisted on scrubbing their children clean at every sign of dirt. Cleanliness is a good thing, of course, but so is exposure to soil, with dirty hands and faces the evidence of time well spent outside.

And that brings up another problem of the modern world. The benefit of spending time in dirt is in part because of the many types of bacteria found in soil — scientists say it is one of the most diverse habitats on Earth. Biodiversity is decreasing in soil as well as other parts of our modern environment, decreasing the benefits of exposure for humans.

Now, as we continue to do research, the scientists can tell us with some confidence that getting out in nature is helpful to health, and the more varied the bugs in nature, the better. The next puzzle to answer and to promote is how farmers, ranchers, home gardeners, outdoor enthusiasts — all of us, really — can increase the biodiversity in our environment. When that happens, we will all be healthier.