Muddy Boots

Feet of two people wearing raining boots jumping in the mud

You kids better not track that mud into the house!

This is Sandra Tsing Loh with the Loh Down on Science…remembering something my mother used to say. Or more like, yell!

But science asks: Could dirt actually be GOOD for you?

Marja Roslund from the University of Helsinki, Finland, and her colleagues wondered. So they collected skin, blood, and fecal samples from seventy-five toddlers at different daycare centers. So-called NATURAL daycares were landscaped to have more soil and plants, whereas URBAN daycares had less. They tested samples from kids in each setting and compared their immune systems.

Results? Children who learned in a natural environment had more healthy germs! Those who learned in urban daycare centers had weaker immune systems and fewer healthy bacteria.

But don’t worry! Scientists planted the same dirt and plants from natural environments at the urban daycares. This introduced new, HEALTHY bacteria! In a month, those children grew healthier immune systems!

So except for keeping her floors clean, my mother was–shall we say–misguided. Although swimming right after eating? Still not a good idea!

Roslund, M. I., Puhakka, R., Grönroos, M., Nurminen, N., Oikarinen, S., Gazali, A. M., Cinek, O., Kramná, L., Siter, N., Vari, H. K., Soininen, L., Parajuli, A., Rajaniemi, J., Kinnunen, T., Laitinen, O. H., Hyöty, H., Sinkkonen, A., & Group, A. research. (2020). Biodiversity intervention enhances immune regulation and health-associated commensal microbiota among daycare children. Science Advances, 6(42), eaba2578.