Turning playgrounds into little forests improves the immune system of day­care chil­dren

HELSINKI, Finland — Kids love when it’s time for recess. While a few minutes running around on an asphalt playground may be fun, a study finds a few minutes in a mini forest can improve your health. Researchers in Finland say children in daycare who had their urban playgrounds turned into healthy green spaces saw rapid changes in their immune system.

The study, coordinated by the Natural Resources Institute Finland (Luke), discovered that exposing children to microbes found in nature increases the diversity of the human microbiome. Researchers say the high level of hygiene, urban lifestyles, and insufficient contact with nature lowers this diversity. When children have fewer microbes in their organ system they’re at higher risk for immune system disorders. These include atopy, diabetes, celiac disease, and allergies.

Children who grow up in rural areas however, usually have regular contact with the countryside. The study finds these youngsters generally have lower chances of developing immune system problems. Based on this data, the Finnish team experimented with getting children in urban areas regular contact with grassy areas. Their results show three to five-year-olds who spend five days a week in nature increased their microbe diversity in just one month.

“This recently published study of daycare children is the first in which these changes offering protection against diseases have been found when adding diversified aspects of nature to an urban environment,” says Luke research scientist Aki Sinkkonen in a media release.

“The results of this study are encouraging when looking for new opportunities for the prevention of immune system disorders. Further studies aimed to reach this goal are already underway,” Heikki Hyöty from the University of Tampere adds.

Playground makeover

Ten daycare centers in the cities of Lahti and Tampere had their tile and gravel-coated yards renovated to include forest undergrowth, lawn turf, and planter boxes. Over the next month, researchers studied how the microbial diversity in the skin of 75 children changed. The team also compared the readings to three to five-year-olds in normal daycare centers (no green spaces) and nature daycare centers, which take regular field trips.

Nature Playground
(Credit: University of Helsinki)

Study authors say the children in renovated playgrounds had increases in gammaproteobacteria, which strengthens the skin’s immune response. The kids also had higher levels of multifunctional TGF-β1-cytokine in their blood and less interleukin-17A, which has a connection to immune-transmitted diseases.

“This supports the assumption that contact with nature prevents disorders in the immune system, such as autoimmune diseases and allergies,” Sinkkonen says.

“We also found that the intestinal microbiota of children who received greenery was similar to the intestinal microbiota of children visiting the forest every day,” adds researcher Marja Roslund from the University of Helsinki.

Getting kids in touch with nature

Study authors recommend all daycare centers take a cue from the study and turn their playgrounds into greener areas. The study contends this will also result in improved motor skills and concentration power among youngsters.

“We should modify our daily life so that we can be in contact with nature. It would be best if children could play in puddles and everyone could dig organic soil. We could take our children out to nature five times a week to have an impact on microbes,” Sinkkonen concludes.

The study appears in the journal Science Advances.