A study in Finland showed, for the first time, that the immune system of children ages 3-5 improved when forest undergrowth, lawns, and planter boxes were added outside daycare centers.
Dozens of comparative studies have previously found that children who live in rural areas and are in contact with nature have a lower probability of catching an illness resulting from disorders in the immune system—and a lower risk of developing coeliac disease, allergies, atopy, and even diabetes.
The recent study shows that repeated contact with nature-like elements five times a week diversified the body’s microbes which offered protection against diseases transmitted through the immune system in daycare children.
“This 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 Aki Sinkkonen, research scientist, who led the study for the Natural Resources Institute Finland (Luke).
The study published in Science Advances, measured what happened when children planted and tended crops in planter boxes, and played on lawns that were added to paved, tiled, or gravel-coated yard areas at daycare centers.
Biodiversity increases healthy microbial diversity
75 daycare children were monitored for one month at ten daycare centers in Lahti and Tampere. Changes in microbes in children who attended daycare with the added nature areas were compared with children who attended normal daycare centers (with no green yard area) or daycare centers with no green yard area, but regular field trips.
Playing in the biodiverse yards over a one month period increased microbial diversity in the children’s skin. There were also changes in blood counts. Increases in gammaproteobacteria, which strengthen the skin’s immune defense, increased the content of the multifunctional TGF-β1-cytokine in blood and reduced the content of interleukin-17A, which is connected to immune-transmitted diseases, according to a statement from Heikki Hyöty, professor of virology from the University of Tampere who participated in the study
“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,” says dissertation researcher Marja Roslund from the University of Helsinki.
Based on this study and previous comparative studies, Sinkkonen says children’s motor skills and ability to concentrate will also improve, with the close relationship to nature.
When we are in contact with nature, we expose ourselves to a broad range of microbes, activating different parts of our defensive system.
The researchers suggest leaving autumn leaves to decompose naturally, rather than carrying them away, and allowing the fallen tree limbs to decay naturally on the ground.
“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 we could take our children out to nature five times a week to have an impact on microbes”, Sinkkonen says, which will also keep your tetanus vaccination effective.