The ongoing extinction crisis affecting ecosystems worldwide is paralleled by a significant decline in microbial diversity within human bodies. This loss has profound implications for health, as a growing body of research links the health of our internal microbiomes with the biodiversity in our external environments.
Human bodies function similarly to cities, populated by vast communities of microorganisms, including viruses, fungi, and bacteria. Collectively known as the human microbiome, these microbes play crucial roles in digestion, immune response, and hormonal regulation. While many are familiar with the gut microbiome, these microorganisms inhabit various parts of the body, such as the skin, nostrils, and even the eyes. In fact, approximately **90%** of the cells in the human body are microbes, creating a dynamic ecosystem that can influence overall health.
The relationship between human health and environmental biodiversity is becoming increasingly evident. “What’s happening inside our own bodies is kind of mirroring what’s happening at a global ecosystem level,” states Anastasia Theodosiou from the University of Glasgow. This interconnectedness is reflected in the concept of “outer and inner layers of biodiversity,” where a richer diversity of species in our surroundings promotes healthier microbial communities within us.
Research indicates that urban environments often experience higher rates of inflammatory disorders, including allergies, asthma, and type 1 diabetes. While the incidence of infectious diseases has decreased, autoimmune diseases are on the rise, with some studies suggesting a correlation with the loss of microbial diversity. Ina Schuppe Koistinen, an associate professor at the Karolinska Institute, notes that this phenomenon is linked to what is known as the “biodiversity hypothesis.”
This hypothesis gained traction following the Karelia Allergy Study, which examined differences in allergic reactions between genetically similar populations in Finland and Russia. Those living in urban Finland exhibited significantly higher rates of allergies compared to their counterparts in rural Russia, where such conditions were rare. The findings highlighted the adverse effects of reduced exposure to natural environments on human health.
As the world faces escalating deforestation, with over 8 million hectares of forest lost last year alone, the implications for public health are alarming. By 2050, it is projected that approximately **70%** of the global population will reside in urban areas, further diminishing contact with nature. This disconnection has been linked to weakened immune systems, rising asthma rates, and increased anxiety.
Moreover, the destruction of natural habitats is a leading driver of infectious disease outbreaks. As wildlife and humans encroach upon each other’s territories, the risk of disease transmission grows. Recent studies emphasize the importance of preserving ecosystems, with research suggesting that protecting the Amazon could prevent millions from falling ill.
The solutions to these interconnected crises also present opportunities for improvement. A comprehensive review of **1,550 studies** conducted last month found that urban biodiversity initiatives, such as tree planting and habitat restoration in parks, yield significant health benefits. Erica Spotswood, a senior scientist at the San Francisco Estuary Institute, explains, “If you take action for biodiversity in cities, these actions will also likely yield benefits to human health.”
Immediate benefits often arise from increasing interactions with nature. For instance, a study from Finland demonstrated that just one month of exposure to healthy, biodiverse soils through gardening enhanced skin bacteria and the body’s immune response. This underscores the vital connection between our microbial health and the natural world.
As communities strive to protect their internal ecosystems, the urgency to maintain biodiversity in our external environments grows. The health of our microbiomes is intricately linked to the health of the planet, highlighting the need for collective action to foster a nature-rich existence.
The narrative of extinction extends beyond the visible loss of species; it encompasses the hidden decline of microbial diversity that underpins human health. As the world grapples with these intertwined crises, a commitment to preserving the natural world becomes essential for ensuring the well-being of both ecosystems and humanity.
