A lack of exposure to a “natural environment” could be resulting in more urban dwellers developing allergies and asthma, research has suggested.
Finnish scientists say certain bacteria, shown to be beneficial for human health, are found in greater abundance in non-urban surroundings.
The microbiota play an important role in the development and maintenance of the immune system, they add.
The findings appear in the Proceedings of the National Academy of Sciences.
“There are microbes everywhere, including in the built environment, but the composition is different between natural environments and human-built areas,” explained co-author Ilkka Hanski from the University of Helsinki.
“The microbiota in natural environments is more beneficial for us,” he told BBC News.