Environment is cleaner. Your immune system has never been so unprepared
Excerpted from “An Elegant Defense: The Extraordinary New Science of the Immune System,” published on Tuesday by William Morrow. Should you pick your nose? Don’t laugh. Scientifically, it’s an interesting question.
Should your children pick their noses? Should your children eat dirt? Maybe: Your body needs to know what immune challenges lurk in the immediate environment.
Should you use antibacterial soap or hand sanitizers? No. Are we taking too many antibiotics? Yes.
“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.
“Get rid of the antibacterial soap. Immunize! If a new vaccine comes out, run and get it. I immunized the living hell out of my children. And it’s O.K. if they eat dirt.”
Dr. Lemon’s prescription for a better immune system doesn’t end there. “You should not only pick your nose, you should eat it,” she said.
She’s referring, with a facetious touch, to the fact our immune system can become disrupted if it doesn’t have regular interactions with the natural world.
“Our immune system needs a job,” Dr. Lemon said. “We evolved over millions of years to have our immune systems under constant assault. Now they don’t have anything to do.”
She isn’t alone. Leading physicians and immunologists are reconsidering the antiseptic, at times hysterical, ways in which we interact with our environment.
Why? Let us turn to 19thcentury London.
The British Journal of Homeopathy, volume 29, published in 1872, included a startlingly prescient observation: “Hay fever is said to be an aristocratic disease, and there can be no doubt that, if it is not almost wholly confined to the upper classes of society, it is rarely, if ever, met with but among the educated.”
Hay fever is a catchall term for seasonal allergies to pollen and other airborne irritants. With this idea that hay fever was an aristocratic disease, British scientists were on to something.
More than a century later, in November 1989, another highly influential paper was published on the subject of hay fever. The paper was short, less than two pages, in BMJ, titled “Hay Fever, Hygiene, and Household Size.”
The author looked at the prevalence of hay fever among 17,414 children born in March 1958. Of 16 variables the scientist explored, he described as “most striking” an association between the likelihood that a child would get hay fever allergy and the number of his or her siblings.
It was an inverse relationship, meaning 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.
The paper 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.
“Over the past century declining family size, improvements in household amenities, and higher standards of personal cleanliness have reduced the opportunity for cross infection in young families,” the paper continued. “This may have resulted in more widespread clinical expression of atopic disease, emerging in wealthier people, as seems to have occurred for hay fever.”