A collaborative study involving the University of Helsinki, Natural Resources Institute Finland, and Tampere University has revealed significant health benefits from one month of indoor gardening, notably increasing the bacterial diversity on the skin and elevating levels of anti-inflammatory molecules in the blood. Mika Saarenpää, in his doctoral thesis, investigated enhancing immune regulation among urban residents through engaging in daily activities like urban gardening. This study builds on previous findings that exposure to microbially rich, nature-derived materials alters human microbiota. Participants enjoyed urban gardening using a growth medium similar to forest soil, rich in microbial diversity, which showed potential long-term benefits for immune system functioning, contrasting with a control group using a microbially poor peat-based medium.
Saarenpää highlighted the critical implications of these findings against the backdrop of increasing urbanisation, which correlates with a rise in immune-mediated diseases such as allergies and asthma, which lead to high healthcare costs. This research underscores how urban settings, which typically limit microbial exposure and thus change the human microbiota, increase the risk of these diseases. Saarenpää’s research demonstrates that natural and enjoyable activities like gardening can significantly enhance the microbiota diversity of healthy adults, thus aiding in regulating the immune system, marking a significant step in understanding how everyday activities can influence health at a microbial level.
The study shows that urban gardening offers a straightforward and economical way to improve health. Using standard flower boxes and readily available plants requires minimal space and investment. The positive changes in microbiota and immune system regulation observed within just a month encouraged many participants to continue the activity, indicating the potential for long-term health benefits. Saarenpää suggests that increasing microbe-mediated immunoregulation could reduce the risk or alleviate symptoms of immune-mediated diseases and, if adopted on a broader scale, could significantly reduce healthcare costs and enhance life quality.
The duration of the beneficial effects on skin microbiota and anti-inflammatory cytokines remains uncertain. However, Saarenpää posits that gardening could lead to more continuous regulation of the immune system if gardening becomes a sustained hobby. This ongoing engagement with nature and microbial-rich environments could become a pivotal part of maintaining health in urban settings.
Saarenpää also underscores the importance of introducing children to microbial-rich environments early in life, given the active development of the immune system during childhood. He advocates using planter boxes filled with diverse soil in kindergartens, schools, and hospitals, particularly in urban areas, to maximise health benefits without accompanying risks. Ensuring that gardening practices are safe—such as maintaining unbroken skin on the hands and avoiding the inhalation of dusty growing media—is crucial for reaping the health benefits of urban gardening. This responsibility to create healthier environments for children can be a powerful motivator for urban planners, educators, and policymakers.
Concluding his research, Saarenpää stresses the critical dependency of our health on the diversity of nature and soil, highlighting how our well-being is intricately linked with other species. He envisions urban areas rich in natural environments that provide beneficial microbial exposure, reducing the need for artificially designed products and fostering a healthier, more sustainable interaction between humans and their environment. This vision aligns with a broader understanding of environmental and health sciences, suggesting that enhancing our contact with nature could be a simple yet profound way to improve public health.
More information: Mika Saarenpää et al, Urban indoor gardening enhances immune regulation and diversifies skin microbiota — A placebo-controlled double-blinded intervention study, Environment International. DOI: 10.1016/j.envint.2024.108705
Journal information: Environment International Provided by University of Helsinki
