There’s been a lot of talk about the ill effects of loosing touch with nature, but most has focused on how it affects the spirit or leads to behavior that damages the natural world. Now, here’s a physical health reason to drop the smartphone and take a walk in the woods. Reminds me of a remark my quite healthy dairy farming neighbor made the other day: “You’re not a real Vermonter unless you’re knee deep in shit.”

From the Editor’s Choice section of the 8 June issue of Science:

MICROBIOLOGY

Hygiene Can Hurt

As human societies urbanize, chronic inflammatory disorders become more apparent. The hygiene hypothesis suggests that individuals exposed to infection in childhood are less likely to develop inflammatory disease because exposure to microorganisms is important for stimulating responses that maintain epithelial cell integrity. Hence, in urban environments, reduced contact with the full diversity of the microbial world may be leading to the increased incidence of inflammatory disorders. Hanski et al. took a random sample of 118 adolescents from towns, villages, and isolated dwellings in eastern Finland, tested their immune function and allergic responses, surveyed their skin microflora, and investigated the biodiversity within their homes. They found several significant correlations, not least that low biodiversity was surprisingly strongly associated with atopy, and concluded that humans need to interact with natural environments for their physical health, not just for their peace of mind.

Proc. Natl. Acad. Sci. U.S.A. 109, 10.1073/pnas.1205624109 (2012).