Why are food allergies on the rise?

For me … it all started with beer.

In my early twenties, while friends were kicking back glass after frosty glass of thick, rich beers like stouts, ales and porters, I had already resigned myself to a lifetime of lightweight, watery beer.

I had learned the hard way that drinking those heavier beers meant suffering the consequences: lethargy, itchy eyes, creepy-crawly skin and a persistent tickle in my throat. I chalked it all up to an allergic reaction to some ingredient in those unfiltered pints.

Researchers estimate that 12 million people in the United States, roughly 4 percent of the population, have an allergic reaction to food or beverages. And some doctors and researchers have said that the number of allergies is on the rise.

While there is evidence that allergies to some foods are rising, the picture of food allergies on the whole is incomplete. And if my case is any indication, many people could be reporting something other than a true allergy, contributing to the sense that the numbers are increasing.

“There are good studies showing a rise in allergic diseases like asthma, hay fever and dermatitis but no one was carefully tracking food allergies over the past decades,” says Dr. Scott Sicherer, allergy researcher at Mount Sinai School of Medicine, in an e-mail statement.

He goes on to say that the available research is “spotty and imperfect,” and reports of rising food allergies come from many different sources including allergy researchers, doctors, parents and school nurses.

But it’s not clear that we can rely on many of these reports. Physicians who aren’t allergy specialists thought that the total number of food allergies was three times higher than the current research estimates, according to a 2007 survey by researchers at Louisiana State University. In addition, they often attributed headaches, an unrelated symptom, to food allergies six times more often than specialists.

And we non-physicians appear to be horrible at diagnosing our own food allergies. A 2005 Danish study showed that while 16 percent of adult volunteers reported having a food allergy, only about 3 percent actually showed allergic symptoms when fed the offending food.

In my case, by my late twenties, my perceived allergy seemed very real. My problem had moved beyond beer. I was feeling tired all the time, having gastrointestinal problems and was taking antihistamines regularly for congestion in my sinuses. If asked if I had an allergy at that point, the answer would have been an emphatic yes.

I eventually found out that I’m not allergic, but rather intolerant to high levels of gluten, a protein found in grains and present in tasty, unfiltered pints. Simply put, an allergy is something that gets a response from the immune system and an intolerance is not.

“We do know people may think they are allergic, but really are not and to really know you would need to pull people from the general population randomly and do extensive tests – which isn’t easy,” says Sicherer.

Despite the challenges to determining the number of food allergies, it appears that for some foods they are rising. Sicherer’s own work showed that peanut allergies doubled from 1 out of 250 young children in 1997 to 1 out of 125 in 2002. His study, however, was also based on a sample of people self-reporting their own allergies.

“I find it hard to believe we are imagining an increase,” says Sicherer. “Many of us over the age of 35 remember being in school and having few classmates with problems like these. Now our children have multiple classmates with multiple food allergies.”

Sicherer points to the “hygiene hypothesis” – that our hyper-vigilance against germs via vaccinations, antibiotics and sanitation is actually making our kids more allergic to food and to other things in our environment. The idea is that with no natural bugs left to fight, the immune system starts going after things that aren’t actually germs.

If you find that hard to swallow, others have proposed that as the world gets smaller, we are eating more exotic foods that our systems aren’t adapted to. “One of the classic examples [in the U.S.] is that we never used to see kiwi allergy, but no one ever used to eat kiwis. Now everybody eats kiwis and we have lots of kiwi allergies,” says Dr. Hugh Sampson, a colleague of Sicherer’s, in a 2006 issue of European Molecular Biology Organization Reports.