March 13, 2019
“I tell people, when they drop food on the floor, please pick it up and eat it,” said Dr. Meg Lemon, a dermatologist in Denver who treats people with allergies and autoimmune disorders, to the New York Times.
This statement — as gasp-inducing as it may be — represents an evolving outlook on the human immune system. Leading physicians and immunologists are reconsidering the overly-concerned-with-antiseptic ways in which we interact with our environment.
The thing is, our immune system evolved to work by interacting with the world around us. But current practices lead experts to believe that our immune systems need a job.
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Rather than eat food off the floor, humans eventually learned the benefits of washing our hands, sweeping our floors, cooking our food and avoiding some “risky” foods altogether, Men’s Health explains. But this hygienic vigilance removed the regular interaction our immune system had with friendly bacteria and parasites that helped to teach and hone it — training it to be more resilient.
A highly influential 1989 paper published in BMJ, titled “Hay Fever, Hygiene, and Household Size,” in which researchers found a “most striking” association between the likelihood that a child would get hay fever (which is really just allergies) and the number of his or her siblings. The more siblings the child had, the less likely it was that he or she would get the allergy. Not just that, but the children least likely to get allergies were ones who had older siblings.
Researchers hypothesized that “allergic diseases were prevented by infection in early childhood, transmitted by unhygienic contact with older siblings, or acquired prenatally from a mother infected by contact with her older children, the Times explains.
However, as time has progressed, families have become smaller as people have fewer children and Western societies are increasingly focused on keeping their homes, bodies, food, water and milk clean and sterilized, Daily Mail reports.
At the same time, the prevalence of allergies has risen. In the U.S. in 2011 there were 50 percent more children with food allergies than in 1997. In that same time frame, there was a 69 per cent increase in skin allergies, according to the Centers for Disease Control and Prevention. And now, of course, there's a good chunk of Americans who think they have a food allergy — but actually don't.
Of course, advances in hygiene have been extremely beneficial for society, improved the health and lives of modern people and greatly reduced the amount of public health concerns people are exposed to.
But the Times suggests the immune system could still benefit from training to make it better at fighting infection – and picking your nose or eating dirty food could be a way to do that.