LACK OF CONTACT WITH NATURE 'INCREASING ALLERGIES'

A report in 'Proceedings of the National Academy of Sciences' has suggested that more urban dwellers are developing allergies and asthma, due to a lack of exposure to a "natural environment"

Finnish scientists say certain bacteria that are beneficial for human health, are found in greater abundance in non-urban surroundings.

Co-author Ilkka Hanski, from the University of Helsinki, told the BBC that the microbiota play an important role in the development and maintenance of the immune system. "There are microbes everywhere, including in the built environment, but the composition is different between natural environments and human-built areas.The microbiota in natural environments is more beneficial for us,"

Examining samples from 118 teenagers, they found that those living on farms or near forests displayed lower allergen sensitivity and had more diverse bacteria on their skin. The study also allowed the team to identify one class of bacteria, known as gammaproteobacteria, which had a "special function".

"It demonstrates that there are different functions between different microbes," he said. One type was singled out as being "strongly linked to the development of anti-inflammatory molecules" and that the more you had of this particular type of gammaproteobacteria on your skin… the more you had an immunological response which is known to suppress inflammatory responses ( to pollen, animals etc)."

Dr Hanski said that there was a tendency for gammaproteobacteria to be more prevalent in vegetative environment, such as forests and agricultural land rather than built-up areas and water bodies and suggested that "apart from reserving natural areas outside of urban areas… it is important to develop city planning that includes green spaces, green belts and green infrastructure,"

Link: www.bbc.co.uk/news/science-environment-17952320