Green yard boosts daycare kids’ immune system

The immune system of daycare children of three to five years has improved following the regulation of having forest undergrowth, lawn turf, and planter boxes added to yard areas of daycare centres, according to an experimental study coordinated by the Natural Resources Institute Finland (Luke).

The study conducted for the first time in the world that a high level of hygiene, an urban lifestyle, and an insufficient contact with nature reduce diversity in the organ system’s microbes.

Homogeneity in microbes increases the risk of disorders in the immune system, such as atopy, diabetes, the coeliac disease, and allergies.

A recent study shows that repeated contact with nature-like elements five times a week diversified the organ system’s microbes that offer protection against diseases transmitted through the immune system in daycare children.

“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,” said Luke research scientist Aki Sinkkonen, who led the study the report of which was run by the Science Advances.

The research groups of Heikki Hyöty, professor of virology, and Juho Rajaniemi, professor of urban planning, from the University of Tampere participated in the study.

“The results of this study are encouraging when looking for new opportunities for the prevention of immune system disorders. Further studies aimed at reaching this goal are already underway,” said Heikki Hyöty.

During the study, forest undergrowth, lawn turf and planter boxes, in which children planted and tended crops, were added to paved, tiled and gravel-coated yard areas at daycare centres.

The report reads “Contact with nature repeated five times a week during one month increased microbial diversity in children’s skin. There were also changes in blood counts. Increases in gammaproteobacteria, which strengthen the skin’s immune defence, 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.”

“This supports the assumption that contact with nature prevents disorders in the immune system, such as autoimmune diseases and allergies”, said Sinkkonen. “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,” said dissertation researcher Marja Roslund from the University of Helsinki.

During the study, 75 daycare children of three to five years were monitored for one month at ten daycare centres in Lahti and Tampere.

Changes in microbes in children who attended daycare centres with green yard areas were compared with children who attended normal daycare centres (no green yard area) or nature daycare centres (no green yard area but regular field trips).