A study conducted by the University of Helsinki, Natural Resources Institute Finland, and Tampere University found that engaging in indoor gardening for a month can lead to an increase in the diversity of bacteria on the skin. This activity was also linked to higher levels of anti-inflammatory molecules in the blood. Mika Saarenpää, in his doctoral thesis, explored the impact of microbial exposure on overall health.The immune regulation of urban residents can be improved through meaningful activities integrated into everyday life, especially by enhancing their contact with nature-derived, microbially rich materials. A study by Saarenpää found that urban gardening, a natural activity for urban residents, may lead to long-term changes in their immune system function. The research subjects who participated in urban indoor gardening for one month experienced increased diversity of bacteria on their skin and higher levels of anti-inflammatory cytokines in their blood.”The group we studied used a growing medium with high microbial diversity that mimics forest soil,” said Doctoral Researcher Mika Saarenpää from the Faculty of Biological and Environmental Sciences, University of Helsinki. In contrast, the control group used a peat-based medium with low microbial diversity. According to Saarenpää, there were no observed changes in the blood or skin microbiota. Peat is the most widely used growing medium globally, and its production has a significantly negative environmental impact. Additionally, Saarenpää’s research suggests that it does not provide the same health benefits as a medium that mimics diverse forest soil.The study’s results are important because as cities grow, there has been a significant rise in immune-mediated diseases like allergies, asthma, and autoimmune diseases, leading to high healthcare expenses. Saarenpää notes, “We live too ‘cleanly’ in cities.”
He also adds, “We are aware that urbanization leads to a decrease in exposure to microbes, changes in the human microbiota, and an increased risk of immune-mediated diseases. This is the first instance where we are able to show that meaningful and natural human activity can enhance the diversity of the microbiota in healthy adults and, at the same time, help regulate the immune system.”Urban gardening offers a simple way to enhance health. Microbial exposure can be easily and safely increased at home year-round. The space and financial investment needed are minimal. In the study, gardening took place in regular flower boxes, and the plants cultivated were easily accessible from the store. Changes were noticed in just one month, and many of the research subjects expressed a desire to continue gardening and transition to outdoor gardening in the summer. According to Saarenpää, microorganisms be-mediated immunoregulation can, at its best, reduce the risk of immune-mediated diseases or even their symptoms. If health-promoting microbial exposure could be increased at the population level, the healthcare costs associated with these diseases could be reduced and people’s quality of life improved.
“We don’t yet know how long the changes observed in the skin microbiota and anti-inflammatory cytokines persist, but if gardening turns into a hobby, it can be assumed that the regulation of the immune system becomes increasingly continuous,” Saarenpää notes.
Saarenpää considers it important to invest in children’s exposure
Paraphrased: Mediated immunoregulation has the potential to reduce the risk of immune-mediated diseases and their symptoms. Increasing exposure to health-promoting microbes at the population level could lead to reduced healthcare costs and improved quality of life for people. Saarenpää suggests that if gardening becomes a regular activity, it could lead to continuous regulation of the immune system. Saarenpää also emphasizes the importance of investing in children’s exposure.The immune system is most active in childhood, making it crucial for children to be exposed to nature and microbes. Introducing planter boxes filled with microbially rich soil in places like kindergartens, schools, and hospitals in densely built urban areas could be beneficial. However, to ensure that urban gardening brings health benefits rather than risks, it’s important for individuals to have unbroken skin on their hands and to avoid inhaling dusty growing media.
“My research highlights the importance of our health being dependent on the diversity of nature, particularly soil. We are just one species among many, and our health is influenced by the range of other species. Ideally, urban areas should prioritize the diversity of nature and soil for the overall well-being of the community.”Saarenpää explains that in some areas, the natural environment is so diverse that exposure to beneficial microbes for health does not have to come from specially designed products.
