How does nature help prevent disease?

The immune system may be a significant pathway explaining how nature and the body work jointly to fight disease, says research.

We all know roaming through woods, countryside or paddling in the sea is good for our wellbeing. Research has discovered that spending time in natural environments protects against chronic illnesses such as depression, diabetes, obesity, ADHD, cardiovascular disease, cancer, etc.

How?

Exactly how nature supports good health is poorly understood. Still, Ming Kuo, director of the Landscape and Human Health Laboratory at the University of Illinois at Urbana-Champaign, thinks the answer is connected to the immune system.

After reviewing hundreds of studies on nature and health, Ming Kuo found twenty-one possible pathways connecting the natural world to health. Interestingly, nineteen out of the twenty-one pathways were linked to the immune system.

 Kuo commented in a press release

“The realization that there are so many pathways helps explain not only how nature promotes health, but also why nature has such huge, broad effects on health”. “Nature doesn’t just have one or two active ingredients. It’s more like a multivitamin that provides us with all sorts of the nutrients we need. That’s how nature can protect us from all these different kinds of diseases—cardiovascular, respiratory, mental health, musculoskeletal, etc.—simultaneously”.

One way to understand this relationship between nature, health, and the immune system, Kuo explains, is that exposure to nature switches the body into “rest and digest” mode, which is the opposite of the “fight or flight” mode. When the body is in “fight or flight” mode, it shuts down everything that is immediately nonessential, including the immune system. 

“When we feel completely safe, our body devotes resources to long-term investments that lead to good health outcomes—growing, reproducing, and building the immune system,” Kuo said. “When we are in nature in that relaxed state, and our body knows that it’s safe, it invests resources toward the immune system”. 

For those who prefer playing a board game or visiting an art gallery to taking a walk in the park, Kuo says some of the same restorative benefits can be obtained. “if you are absorbed and relaxed, chances are your parasympathetic system is happy and your immune system is going to get a boost. That said, these enjoyable indoor activities don’t provide the phytoncides, mycobacterium vaccae, negative air ions, vitamin D-producing sunlight, and other active ingredients found outdoors. So we’d expect a smaller boost than you’d get from being in nature.” 

The findings were published in Frontiers in Psychology Cognitive Science

Reference

Kuo M. (2015). How might contact with nature promote human health? Promising mechanisms and a possible central pathway. Frontiers in psychology, 6, 1093. https://doi.org/10.3389/fpsyg.2015.01093

Press release by Debra Levey Larson: https://aces.illinois.edu/news/immune-system-may-be-pathway-between-nature-and-good-health.