A team from the University of Helsinki engaged 75 toddlers aged 3 to 5 from 10 preschools in the Finnish capital for their experiment. The researchers discovered that just one month of play on a simulated forest floor and among greenery was enough to boost a child’s immune system.
How the Study Was Conducted
The scientists asked preschool staff to create special research lawns by planting moss and typical forest shrubs (including dwarf heather and blueberries), as well as placing plant boxes in the schools. Educators were instructed to allow the children to play on the makeshift forest floor, care for the plants, and dig in the soil to their hearts’ content.
Meanwhile, the researchers systematically analyzed the health of the young participants, paying particular attention to their immune systems. It turned out that these playful interactions led to a rapid improvement in the gut and skin microbiomes of the children.
Compared to other urban children who continued to play on sidewalks, tiles, and gravel during the experiment, the study participants showed an increased number of T-cells and other important immune markers in their blood after just 28 days.
Even in such a short period, the researchers found that the microbial composition on the skin and in the guts of children who regularly played among greenery became more diverse. This diversity is known to be linked to a generally healthier immune system.
“We also found that the gut microbiome of children who interacted with greenery was similar to that of children who visit the forest daily,” confirmed ecologist Marja Roslund.
Conclusions Drawn by the Team
Previous studies have shown that spending time among greenery correlates with immune system health. However, it was not clear until now whether this connection was causal. Therefore, this current study is the first to establish that link, as reported by Science Alert.
While the findings do not answer all questions, they support the theory that changes in the microbial composition of the environment can easily influence children’s microbiomes. Moreover, it strengthens their immune systems. The idea that the environment impacts our immunity is known as the “biodiversity hypothesis.” According to this hypothesis, the loss of biodiversity in urban areas may be at least partially responsible for the rise in immune-related diseases.
On the other hand, contact with nature helps prevent immune system disorders, such as autoimmune diseases and allergies, the scientists noted. They added that spending time outdoors is also beneficial for children’s eyesight and mental health.
“It would be great if children could play in puddles and dig in organic soil,” said ecologist Aki Sinkkonen, a co-author of the study. Overall, to strengthen their immune systems, children should spend time in nature at least five times a week.
Connecting with nature in childhood is also beneficial for the future ecosystems of our planet. According to scientists, children who frequently spend time outdoors are more likely to become environmental advocates in adulthood.
The results of the study were published in the journal Science Advances.