'Dirt' microbes essential for urbanites' health

Those who left their rural settings in search for a better livelihood in metros and lost the opportunity to "play in the dirt", read this again and again.

According to a significant research, people living in urban centres who have less access to green spaces are more likely to have asthma, allergies and other chronic inflammatory disorders.

Why? Because they have a reduced exposure to beneficial microbes that thrive in rural environments.

"Chronic inflammation can lead to all kinds of problems from irritable bowel syndrome to asthma to allergies and even depression," said Christopher Lowry, an associate professor in University of Colorado Boulder.

According to some scientists, the increase of chronic inflammation in wealthier countries is connected to lifestyles that have essentially become too clean.

The so-called "hygiene hypothesis" is based on the notion that some microbes and infections interact with the immune system to suppress inflammation and that eliminating exposure to those things could compromise your health.

The so-called "hygiene hypothesis" among city dwellers is based on the notion that some microbes and infections interact with the immune system to suppress inflammation and that eliminating exposure to those things could compromise your health.

But some microbes and some types of infections are important because they can keep the immune system from triggering inflammation when it is not necessary, as happens with asthma attacks and allergic reactions, the authors noted.

"The idea that we are too clean - that gives the wrong impression. You want people to wash their hands because hygiene is important to avoid infections that are harmful," Lowry noted.

Exposure to "old friends" plays an important role in guarding against inflammatory disorders, the authors said.

Because the "old infections" are largely absent from the developed world, exposure to environmental microbes - such as those found in rural environments, like farms and green spaces - has likely become even more important.

The modern diseases we pick up from school, work and other crowded areas today do not actually lead to lower instances of inflammatory disorders, Lowry commented in the paper published in the journal Clinical & Experimental Immunology.

The authors say this would explain why low-income urban residents - who cannot easily afford to leave the city for rural vacations - are more likely to suffer from inflammatory disorders.

The problem is made worse because people who live in densely populated areas also are more likely to contract crowd infections, which cause more inflammation, they said.