Back in the good old days, very few kids had severe allergies. Now they are everywhere. What happened?
One in every 13 kids has a food allergy. That comes out to an average of two students in every classroom. The number of allergic and asthmatic kids multiplied two or three times over in the late 20th century, and food allergies in particular remain on the increase. The New York Times observes that “each new generation seems to have more severe, potentially life-threatening allergic reactions than the last.”
In the 1970s I didn’t know a single child with a food allergy. I brought a peanut butter sandwich to school every day, causing not one problem. Since then, peanut allergies have skyrocketed, tripling in just the 11 years between 1997 and 2008. We have gone from cafeterias full of peanut butter to banning the stuff altogether. My niece’s camp confiscated the chocolate I sent her because it contained “traces of nuts.”
Experts have some theories about the cause of what they call the allergy epidemic. One is that we’ve gotten too clean.
Urban kids in China are much more likely to be allergic than those who live on farms. The same trend was observed in England as far back as the 1800s. Modern American Amish kids who spend their time in a “manure-splattered cowshed” from an early age, and whose mothers worked in the same place while pregnant, are one of the least likely groups in the developed world to have allergies, according to The Times. The key mechanism at work may be that exposure to a wide variety and huge quantity of microbes is stimulating pregnant women’s immune systems, protecting them and their fetuses from sensitivity to allergens.
But that theory poses a conundrum: a highly-stimulated immune system is what creates allergic reactions. The system misidentifies harmless substances, like nuts, as deadly, and goes into overdrive to attack them. It isn’t the nuts themselves that kill allergic kids — it is their own immune systems’ response to the nuts. Paradoxically, people believe that boosting their immune systems will reduce symptoms of many things, including the common cold, but that is backwards. Cold viruses themselves are harmless; your own immune system causes everything that makes colds miserable.
What may actually be happening in populations like the Amish appears more subtle than just “stimulating” the immune system, which suggests priming it to attack foreign bodies. Instead, exposure to microbes prompts a very specific immune response: making more regulatory T-cells. These white blood cells calm the immune system down when it encounters foreign but non-threatening substances. Newborns usually don’t have a lot of these cells, but pregnant women exposed to many different microbes produce more of them than usual, which appears to protect their babies even after birth.
Regulatory T-cells aren’t the only explanation that has been thrown up the flagpole. Popular Science posits that children today aren’t spending enough time outside, which cheats them of Vitamin D, which at higher levels helps the immune system identify innocuous substances and leave them be. Anne Muņoz-Furlong, CEO of the nonprofit Food Allergy and Anaphylaxis Network, thinks that scientific progress, including hygiene and successful treatments for infections, has left children’s immune systems with little to do, so they go looking for things to attack. As Live Science puts it, they’re bored.
Discovery Fit & Health reports more theories. Food additives and pesticides may be altering the flora in our guts in a way that makes us more sensitive to allergens. Other new things in food, like genetically modified organisms (GMOs) and new proteins in dairy products, may be the culprits. For something completely different, cesarean sections appear to increase children’s risk of developing allergies.
In short, we don’t know what’s going on or what to do about it, but two things are clear. One, we have to figure out how to restore our children’s resilience in the presence of everyday things like peanuts. Two, anti-bacterial soap is not the answer.
Photo credit: Thinkstock/iStock
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