Why do we need nature to stay healthy?
In Pitkäranta, Russian Karelia, development came to a halt after the wars of the 1940s. People continued their traditional way of life, staying closely connected to nature and animals. Meanwhile, on the other side of the border in Finland, industrialization accelerated, and lifestyles changed rapidly. This situation created an intriguing natural experiment, offering researchers a unique opportunity to study how the environment impacts human health.
A few decades later, researchers discovered a striking difference: while allergies were equally common in Finland and Russian Karelia in the 1940s, by the 1980s, Finns had become significantly more allergic. Birch pollen allergy was ten times more common in Finland, and diabetes rates were 6–8 times higher.
Genetics, air pollution, and environmental chemicals could not explain these differences. Instead, biodiversity emerged as the key factor: the richer the surrounding nature, the more diverse the skin microbiota – leading to a more balanced immune system.
Conclusion: Exposure to diverse nature strengthens the microbiota, supports the immune system, and reduces the risk of diseases.
Nature Step to Health – challenging sector-based thinking
Professor Tari Haahtela introduced the Karelia study when launching the Nature Step to Health program in Lahti in 2021. The program, set to run for ten years, examines human health and environmental as an interconnected whole.
“Why do we still think in sectors?” Haahtela asked. “Healthcare, environment, housing – each as separate sectors – even though we know they are deeply connected.”
Allergies, diabetes, inflammatory bowel diseases, cancer, and many neurological disorders – all these are linked to our environment and lifestyle. They burden people’s health and quality of life and strain healthcare systems.
“We need a new way of thinking and collaboration to see the big picture,” Haahtela emphasized.
Collaboration is the core idea behind the Nature Step to Health program. It integrates health and environmental goals in the Lahti region, working to break down sector-based thinking.
Planetary health – why is it a difficult concept?
The Nature Step to Health program is based on the planetary health approach: human well-being and environmental health are fundamentally connected and should be considered as one.
At first glance, planetary health and the Nature Step to Health program may seem complex concepts. They are difficult to explain because they bring together multiple disciplines. We are used to thinking in sectors: medicine handles health, biology studies nature, and engineering focuses on urban planning. When these fields are presented as a unified whole, it can feel abstract and difficult to grasp.
Another challenge is that cause-and-effect relationships are often complex and long-term. For example, the idea that biodiversity loss can weaken the immune system and increase chronic diseases is not as straightforward as the relationship between vaccination and immunity.
