Urban Gardening Can Boost Immune Health, Study

Researchers from the University of Helsinki, Natural Resources Institute Finland, and Tampere University have discovered that urban indoor gardening can significantly enhance the diversity of skin bacteria and increase anti-inflammatory molecules in the blood. This finding sheds light on a simple and accessible way to promote immune regulation and potentially reduce the risk of immune-mediated diseases.

The study involved participants engaging in urban gardening for one month. Those who used a growing medium with high microbial diversity, emulating forest soil, experienced a boost in skin bacterial diversity and higher levels of anti-inflammatory cytokines in their blood. In contrast, the control group using a microbially poor peat-based medium showed no such changes.

"One month of urban indoor gardening boosted the diversity of bacteria on the skin of the subjects and was associated with higher levels of anti-inflammatory cytokines in the blood. The group studied used a growing medium with high microbial diversity emulating the forest soil," explained Mika Saarenpää, first author on the paper published in Environmental International.

Urbanization has led to a significant increase in immune-mediated diseases, such as allergies, asthma, and autoimmune disorders, due to reduced microbial exposure and changes in the human microbiota. Saarenpää's research demonstrates that meaningful and natural human activities like urban gardening can counteract these effects by increasing microbial diversity and contributing to immune system regulation.

The study's findings are particularly significant because urban gardening is an effortless and accessible way to improve health. It requires minimal space and financial investment, and the gardening activities can be carried out year-round using regular flower boxes and readily available plants from stores.

Saarenpää emphasizes the importance of investing in children's exposure to nature and microbes, as the development of the immune system is most active during childhood. Introducing planter boxes filled with microbially rich soil in kindergartens, schools, and hospitals, especially in densely built urban areas, could be a practical solution.

"My research emphasizes the dependence of our health on the diversity of nature and that of soil in particular. We are one species among others, and our health depends on the range of other species. Ideally, urban areas would also have such a diverse natural environment that microbial exposure beneficial to health would not have to be sought from specifically designed products," Saarenpää concluded.