Exposure to dirt and germs and an outdoor-based lifestyle can protect children against disease
(Photo: Creative Commons/Cade Martin, Dawn Arlotta, USCDCP)

According to leading scientists, ultra-sterilized homes may be bad for children’s immune system and could be responsible for the spikes instances of eczema, asthma and hay fever because the immune system is ill-equipped to fight common invaders such as pollen and dust.
In their book Dirt Is Good – to be released on June 6, Dr John Gilbert, Dr Rob Knight and Sandra Blakeslee argue today’s children are too clean for their own good.

Criticising our addiction to cleanliness, the authors – both parents – explain how evidence is growing to show that not only can dirt and germs protect against disease – but that our indoor-based, uber-clean lifestyles are weakening our immune systems.

Dr Gilbert, Director of the Microbiome Centre and a Professor of Surgery at the University of Chicago, said, “The built environment is the place in which our children grow up.”

Dr Gilbert, one of the authors of a renowned study in The New England Journal of Medicine (2016) which compared the immune profiles of Amish children, growing up on small single-family farms, and Hutterite children, who are similar genetically but grow up on large, industrialised farms.

The Amish, living in an environment described as “rich in microbes,” or alternatively, full of barnyard dust, had strikingly low rates of asthma.

Dr Marsha Wills-Karp, Professor of Environmental Health and Engineering at the Bloomberg School of Public Health at Johns Hopkins University, says, “We used to live in much dustier environments.” Although houses are cleaner, the built environment contains many chemicals and airborne particles.

“While you don’t want to go out and expose your child to aggressive infections, you don’t want to create such a sterile environment that their immune system doesn’t develop normally,” she said. “It puts them at risk of developing immune diseases.”

Dr Gilbert says that over the last 150 years, once humans began to understand that microbes cause disease, there has been an attempt to rid our bodies from any type of fungi, virus or bacterium.

Research indicates that not only does early life exposure to microbes shape the immune system, but also the endocrine system, and even the child’s neurodevelopment.

A study from the University of Alberta in Canada found that being exposed to pets from a young age lowered the risk of obesity and results in fewer allergies in addition to creating early immunity to dirt and bacteria.

In another study published last year, Dr Maria Gloria Dominguez-Bello looked at the Amazon basin of South America and found that in rural houses and huts, most of the bacteria were related to the surrounding environment.

She says as houses become more enclosed, the speed at which outside air replaces inside air decreases. “What happens is, we reduce the exposure to external environmental bacteria, so we become the main source of bacteria, our skin, our mouth, we shed bacteria, and the house becomes highly humanised, most of the bacteria in a house in a city will be human,” she said.

Dr Gilbert recommends educating parents about the types of natural exposure that would be most helpful in immune system development given the specifics of their children and their communities.

Harun Nasrullah