By Tim Johnson
It wasn’t so long ago that parents routinely packed their kids off to school with a peanut butter sandwich for lunch. But that’s an unthinkable prospect today. Were we just ignorant to the dangers back then or has there been an actual spike in peanut and other food allergies? “Incidence of food allergies has doubled in the last 10 years, and it’s not just reporting bias or media awareness or schools being more cautious,” says Dr. Charlotte Miller, a pediatric allergist with the Toronto Allergy Group and The Hospital for Sick Children.
So, then, what’s happening all around us, and in our bodies, that’s causing this marked increase? The prevailing theory is known as the Hygiene Hypothesis. Simply put: we’ve become victims of our own compulsion for cleanliness. “In the past 20 or 30 years, we’ve certainly been living more cleanly. Our housing has changed, we take antibiotics, we have vaccinations. So our immune system, which has less infection to fight than it has in the past, has become dysregulated, and has begun to react and become hypersensitive to things in the environment that are harmless,” says Dr. Susan Waserman, an allergist and clinical immunologist at McMaster University in Hamilton, Ont. “Why should anyone become allergic to something like a peanut or ragweed? It doesn’t really make sense.” The hypothesis is supported by the fact that the entire western world, including the United States and Europe, has experienced the same allergy trend. One well-known study compared relatively clean West Germany with more polluted East Germany and found far lower levels of allergies in the East (although, since unification and the westernization of the East, the levels have risen sharply).
Other culprits may also be involved. Although we don’t really understand what’s going on, there’s some evidence, based on work done by American research chemist Soheila Maleki, that dry-roasting peanuts, which is commonly done in western nations, may be linked with allergy, versus boiling peanuts, which is prevalent in other countries. And while it seems counterintuitive, our own preventative measures, such as avoiding peanut exposure for children with a family history of allergy, may possibly be the problem. “In Israel, for example, the babies eat a candy called Bamba, which does have peanuts, but there is very little peanut allergy in Israel,” observes Dr. Waserman. Food allergy rates have risen despite the advice to wait until three years for the introduction of risky foods. “This has therefore contributed to a new hypothesis that we’re perhaps missing a window of opportunity, and we should, in fact, be introducing these allergenic foods at an earlier time, to help the body become tolerant to them,” notes Dr. Miller, adding, “There is an international study looking at the introduction of peanuts at six months. As well, the American Academy of Pediatrics has removed its recommendation that highly allergenic foods be avoided until three years of age. They now recommend that they can be introduced at any age after six months.”
And while there is no indication that we’re reaching a natural tipping point where allergies will begin to ebb, research has given birth to new strategies for possibly fending off food allergies. There is preliminary data that mothers who consume long-chain polyunsaturated fatty acids during pregnancy and breastfeeding may help decrease allergies in their children, so eating small fish (large ones, such as swordfish, are more affected by harmful mercury) may be advisable. Pre- and probiotics in maternal diet may also help ensure the right kind of bacteria colonizes in the baby’s gut. And, observes Dr. Miller, much effort is being poured into finding a vaccine or a cure, although complete immunity seems unlikely. “It’s really the Holy Grail. Everyone’s trying to do it — there’s a lot of excitement and a lot of money going into research in this field. So I think it’s going to happen, but it probably won’t cure you. It will probably allow you to tolerate larger amounts, so you’re safer.”