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Playing In A Natural Environment Boosts A Kid's Immune System Within A Month


Tom Hale

Senior Journalist

clockOct 16 2020, 20:15 UTC

There are many fascinating and surprising links between the human microbiome and wider health. Stephanie Frey/

Switching a child's playground from gravel to natural forest floor could give them a better immune system within just one month by exposing them to a greater variety of skin and gut bacteria. Just as old wisdom says, the new research suggests that city kids could become healthier if they spend more time playing outside in the dirt.

These findings were recently gathered from a trial carried out in Finland by the University of Helsinki. As reported in the journal Science Advances, researchers studied 75 children between 3 and 5 years old at 10 daycare centers in two Finnish cities, Lahti and Tampere, and looked to see how a change in their playing environment altered their skin and gut microbiota as well as the immune markers in their blood.


Four of the daycare centers were given a revamp that turned their gravel playgrounds into a field of forest floor, soil, and grasses. As controls, three daycare centers already had this setting and three others kept their old gravel playground. One month after the change, scientists collected samples of skin, blood, and poop from all of the kids. 

Despite just a few weeks passing, the researchers noted a dramatic difference. The microbiota of the children at the renovated daycare centers had quickly shifted to become more like the microbiomes of children who attended the nature-oriented daycare centers. This change was also reflected in their immune system, with the children at the renovated daycare centers developing a higher ratio of the anti-inflammatory proteins to pro-inflammatory proteins in their blood, indicating their immune system was in beaming shape. 

"We were surprised that the findings were so clear even though we did not get as many participants as we had hoped," Aki Sinkkonen, study author and a research scientist at the Natural Resources Institute Finland in Turku, said in a statement


There are many links between the trillions of microorganisms that live alongside your body and your wider health. It may influence everything from your risk of certain disease and food cravings to your mental health and perhaps even your personality. Researchers are only just learning how bacteria holds this influence over our bodies, with many recent studies looking to understand the interface between human cells and the microbiome.

Whatever the finer mechanism, it’s clear that our surroundings and lifestyles can dramatically affect the richness and diversity of bacteria in our microbiome. Previously, scientists have found that the gut microbiome of traditional hunter-gatherers in the Amazon is richer than that of urban-industrialized people in the US. In turn, this could explain why many people in fully industrialized parts of the world are born with certain autoimmune disorders like asthma and allergies.

As this new playground study shows, however, a little work can go a long way in a very short space of time.

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  • Human Microbiome,

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