The study, published Monday in Nature Microbiology, found that the more urbanized a settlement was—meaning the more densely populated—the more diverse the biome of the settlement’s homes and its inhabitants were, especially when it came to fungi.
Thus, in their efforts to make their homes more clean or sterile, people living in urban areas may be actually making them more prone to certain kinds of fungi and bacteria.
To conduct the study, researchers examined the microscopic materials in homes as well as the bodies of those homes’ inhabitants.
Although the urban dwellers reported cleaning their homes more than those living in rural settlements, researchers found that surfaces in the urban homes “had a greater diversity of fungal species associated with human skin,” according to the press release. Urbanites were also found to have a greater diversity of foot fungus than their rural counterparts, despite the assumption some may have that the urban homes were “cleaner.”
The research sheds light on some of the disadvantages of urbanization, which is associated with many of the health problems people in more developed countries and areas face today. According to the Rutgers research team, increased urbanization usually goes hand-in-hand with fewer infectious diseases, but is also associated with “obesity, asthma, allergies, autism and other disorders.” Further, urban dwellers’ microbiomes—the helpful bacteria in our bodies that help digest food and perform other functions—are drastically less diverse than those of rural dwellers.
The study’s authors said more research is needed to explore the effects of urbanization on the health of humans, a species originally adapted to live as hunter-gathers in small groups.
“We are just now starting to quantify the effect of cutting ourselves off from the natural environment with which we as humans co-evolved and of replacing it with a synthetic environment,” study co-author Rob Knight, a professor at the University of California-San Diego, said. “What’s next is to identify the specific differences associated with urbanization that have a health impact and to design interventions to reverse them.
