Forget a spike in the pollen count or increased exposure to pet dander, some experts believe clean living is to blame for the rising allergy epidemic. No, they’re not kidding.
Although no one knows why the incidence of allergies is skyrocketing in this country, a leading theory holds that our world (at least in the
United States and other Western countries) is simply too clean. Some researchers call this the “hygiene theory.” Marc Rothenberg, M.D., Ph.D., section chief of Allergy and Clinical Immunology at Children's Hospital Medical Center of Cincinnati, calls it the “delinquency theory,” as in, the immune system has so little to do, it turns into a kind of physiological juvenile delinquent just itching to get into trouble.
The Hygeine Theory:
The problem stems from the tremendous advances we’ve made in the past 50 years in combating infectious diseases, parasites and other pathogens. With vaccines eliminating many previously common childhood diseases, penicillin vanquishing others, and the American penchant for cleanliness (just think about the tremendous explosion in sales of antibacterial wipes, soaps and lotions), a germ doesn’t have a chance.
“The immune system’s function is to recognize the difference between self and foreign bodies,” Rothenberg explains. “Self is fine, foreign bodies are bad. Yet many foreign bodies you come in contact with (such as the hundreds of food proteins you eat and thousands of molecules you breathe in daily) are also fine.”
The immune system has to learn at an early age how to tell the good foreign bodies from the bad, just as a toddler has to learn what “hot” means. The fewer germs your immune system encounters in childhood, however, the less likely it will learn the difference. Instead, it may just start attacking all foreign bodies – as well as your own body. The result: allergies.
Other theories for the increasing prevalence include increased airborne pollutants, rising levels of indoor allergens due to better and tighter construction methods and poor ventilation. Even global warming may play a role: One study predicted that rising carbon dioxide levels associated with global warming could lead to an increase in the incidence of allergies to ragweed and other plants by mid-century.