In Finland, the relationship between nature and children’s health has gone from popular intuition to conclusive scientific evidence. In recent years, various studies have made it clear that children who grow up in frequent contact with natural elements develop a more robust immune system and are less exposed to diseases that affect millions of people in urbanized societies.
This is supported by dozens of previous comparative studies, which have identified that children raised in rural environments are less likely to suffer from diseases associated with immunological disorders, such as celiac disease, allergies, atopy and certain types of diabetes.
The scientific background for this observation is based on a widely accepted principle in modern microbiology: each human being constitutes an ecosystem composed of billions of microorganisms—bacteria, viruses and fungi—that even outnumber human cells themselves by a ratio of four to one.
The influence of these microbes on the health and development of the organism is so decisive that they are currently recognized as one of the most influential factors in human functioning.
The central hypothesis states that Direct and repeated contact with nature diversifies the microbiotaa key process to train and strengthen the immune system during childhood.
It is this ecological connection that has motivated institutions like the Natural Resources Institute of Finland (LUKE) to focus their research on the tangible impact of renaturalization in the playgrounds of urban daycare centers.
The turning point came in 2021, when a pioneering study carried out in a Finnish nursery was published in the magazine Science Advancespresenting results that went beyond the scientific field to influence public policy and educational management.
The team led by the scientist Aki Sinkkonenby LUKE himself, demonstrated that the systematic introduction of natural elements—such as forest soils, native plants, and growing spaces—into children’s daily lives increased microbial diversity in their bodies.
During the study, The children had contact with these elements five times a week, which led to relevant changes in the composition of their microorganisms.. The analyzes showed that these minors developed a greater variety of microbes on the skin, mouth and intestine, a pattern associated with a better defense capacity against immune-mediated diseases.
Blood samples revealed a higher concentration of T cells, immune agents crucial for protection against infections, while the intestinal microbiota showed a decrease in bacteria belonging to the genus Clostridiumlinked to inflammatory diseases.
Likewise, skin samples indicated a lower presence of bacteria Streptococcuswhich tend to trigger infections. Aki Sinkkonen emphasized the significance of these findings: “This is the first time these changes have been found to offer protection against disease by adding various aspects of nature to an urban environment.”.
According to the expert, the results obtained made it possible to establish, on a scientific basis, a specific recommendation on how natural environments can be integrated within a city, for the direct benefit of children’s health.
Following these conclusions, the Finnish Natural Resources Institute expanded the research with an ambitious national project. Instead of a single daycare center and barely 75 childrenthe current survey involves 43 daycare centers throughout the countrycombining biological samples and questionnaires for parents about infections and diseases of their children.
The objective is to analyze with scientific rigor How changes in the landscape of schoolyards influence the microbiota of hair, saliva, feces and skin of minors.
The scope of the study was supported by the government, which allocated one million euros in subsidies to transform children’s recreational spaces: more green areas, composting facilities, orchards and gardens with native flora. Additionally, it is planned to collect infectious disease data among students and evaluate the longitudinal impact of this strategy at the national level.
The case of the Humpula daycare, in Lahti (north of Helsinki), has become emblematic of the movement. The original experiment that motivated national expansion was carried out here.
The center removed conventional grass from its patio and installed a 10-square-meter, 30-centimeter-deep portion of forest soil, loaded with natural seeds and wild microorganisms. Sinkkonen, present during the implementation and observation of the process, highlighted the meaning of the intervention by explaining: “This area hasn’t been forested in 200 years, so this is a substitute”.
Practical results were not long in coming: under Sinkkonen’s supervision, the children interacted daily with mud, plants and insects. Everyday activities such as preparing a “chocolate cake” made with dirt and sand became part of everyday life.
In addition, the creation of a garden made it possible to collect fresh vegetables for school nutrition, reinforcing the connection between nature, food and health. The Humpula nursery has become a reference model for the rest of the country, being the headquarters of the initial study and a tangible example of the achievements achieved through renaturalization.
If the Humpula results manage to replicate consistently throughout Finland, authorities see an unprecedented opportunity to reduce the national health and economic burden associated with immunological and infectious diseases.
Reducing cases of allergies, inflammatory pathologies and autoimmune disorders could free up significant resources from the public health system.
The enthusiasm among educators and officials is palpable. Humpula’s experience has not only improved the daily health and well-being of minors, but also shows a promising path to preserving the quality of life of future generations without resorting to costly interventions or invasive medical procedures. The new wave of renaturalized gardens is emerging as a silent revolution in the prevention of diseases from childhood.
