Nuts. Shellfish. Milk. Wheat. Raw vegetables. Eggs. Soy.
These are just some of the most common food allergens—the foods that, at best, can give someone digestive issues or a rash; at worst, they can put someone into anaphylactic shock, which can be deadly.
You can probably think of at least one person you know who has a food allergy. But figuring out just how many people have food allergies on a national scale is surprisingly complicated. Now researchers have taken a new approach to coming up with a number based on documentation in millions of electronic medical records.
Past estimates have largely been based on surveys—essentially, people are asked if they have food allergies, and they say yes or no. Experts assume that people tend to exaggerate their allergies on these sorts of questionnaires (at least, they say they have allergies when doctors might disagree). The gold standard for coming up with prevalence rates is having a large group of adults and children do a food challenge, an evaluation in which people eat increasing amounts of the thing they think they're allergic to until they have a reaction, all under a doctor's supervision. Though studies like these have been done in other countries like Australia, they haven't yet been done in the US, likely because they require so much time and money.
Getting a good read on the number of people with food allergies nationwide might seem like a pretty unimportant problem; to some, they may already seem to get a lot of attention (does the Italian place really need that gluten-free option?). But the truth is that people with food allergies have to stay constantly vigilant. "Food allergies highly impact a person's quality of life. Every meal, every snack, every social event, holidays, travel, restaurants, school, camps—everything we do, every celebration, it all has to do with food," says Scott Sicherer, a professor of pediatrics, allergy and immunology at the Icahn School of Medicine at Mount Sinai. That need has resulted in policy changes, like putting warnings about wheat, soy, or nut content in clear language on the packaging of processed foods; it's what sparked the outrage at the jacked-up prices of EpiPens.
And what can happen if you don't pay enough attention to people with food allergies? "They die," says James R. Baker, Jr., the CEO and chief medical officer of Food Allergy Research & Education (FARE), a nonprofit advocacy group for people with food allergies.
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Understanding the prevalence of food allergies can also help allocate funding towards studying them. Researchers have lots more questions about allergies—who gets them? What determines the severity of the reaction? Why do some people outgrow food allergies they had as kids while others struggle with them through adulthood? "You want to know how big a problem it is before you start throwing resources at it," says Matthew Greenhawt, chair of the American College of Allergy, Asthma and Immunology Food Allergy Committee and an allergist at Children's Hospital Colorado.
These questions are critically important today as some data has suggested that the prevalence of food allergies is rising in the United States. If researchers can find what kinds of environmental factors might be fueling the growth, they might also be able to stall it. They're starting to come up with some treatments or prevention methods for food allergies, like the recent recommendation to feed peanuts to babies to prevent allergies from developing later.
Research into allergies already doesn't get much funding, and with the Trump administration threatening to slash the budget to the National Institute of Allergy and Infectious Diseases, which funds a number of allergy studies, compelling evidence to keep the agency going could be crucial.
In this recent study, published in May in the Journal of Allergy and Clinical Immunology, the researchers analyzed the electronic medical records of 2.7 million patients seen by a Boston medical group over the course of 13 years. They found around 97,000 of them—3.6 percent—had listed food allergies. They were then able to compare allergens and demographic information to find which were the most common (shellfish was the most common allergen, and women and Asians were more likely to have allergies).
Those numbers are within the range of previous findings, the researchers write. But they might still be wrong, as people might have reported incorrectly in surveys, perhaps even exaggerated their allergies as awareness of them has increased. And these estimates probably can't be extrapolated to the national scale, since allergies vary a lot regionally and the demographics don't reflect those of the entire country, the study authors note.
The three food allergy experts who spoke with Tonic agree that the study was sort of helpful in that it provided a "snapshot" of food allergies within a very specific, limited population. And studies analyzing electronic medical records could be useful in the future, though these records are notoriously inconsistent in their formatting and, frequently, inaccurate.
But this isn't the final answer on the question of prevalence of food allergies. "I'm not saying this is the rate, it's a rate…we don't know what the true rate is," Greenhawt says. FARE, the advocacy group, recently launched patient registry to gather more data on who has food allergies to provide researchers with more data to study.
Still, there are things we can do to ease the burden of food allergy on those around us. "Ask questions, have empathy," Greenhawt says. There are parts of the country where awareness about food allergy is low, where people are embarrassed to admit that they can't eat something. And that can be dangerous.
"People think this is some type of lifestyle issue. This is a disease, it's an illness. It's not something people choose to have. Folks need to understand that and to try and make accommodations," Baker says. "Don't throw peanuts at kids. Don't allow children to bully them. Let them live as complete lives as possible." Read This Next: The Living Hell of a Latex Allergy