Researchers have found that over 10 percent of adults in the U.S. are estimated to have a food allergy, but almost twice as many people as this think they have a food allergy but probably don’t.
The new study published today in JAMA Network Open also found that 19 percent of adults think they are allergic to one or more foods, but that the symptoms they report are inconsistent with a true food allergy.
“While we found that one in 10 adults have food allergy, nearly twice as many adults think that they are allergic to foods, while their symptoms may suggest food intolerance or other food-related conditions,” said Ruchi Gupta M.D. first author of the research from Lurie Children’s Hospital in Chicago and Professor of Pediatrics at Northwestern University.
The researchers surveyed over 40,000 adults in the U.S., also finding that only half of the people who reported a convincing food allergy had been diagnosed by a physician. Nearly half of food-allergic adults had at least 1 adult-onset food allergy, and 38% reported at least 1 food allergy-related emergency department visit in their lifetime.
“Prevalence studies such as this one are much needed to help us further define the scope of the food allergy epidemic in the U.S. To date, there hasn’t been extensive research studying adult food allergy, and this work provides important data points on the growing numbers of Americans affected by this life-threatening disease,” said Lisa Gable, CEO of the organization Food Allergies Research Education (FARE), a non-profit, patient advocacy association which seeks to improve the quality of life and the health of individuals with food allergies and find new treatments.
Serious food allergies are of course a significant problem with FARE reporting that 200,000 Americans require a visit to the emergency room every year due to food allergies. Deaths due to food allergies are rare, but without proper treatment, severe reactions can kill.
“If food allergy is confirmed, understanding the management is also critical, including recognizing symptoms of anaphylaxis and how and when to use epinephrine,” said Gupta.
More worryingly, the research revealed that only a quarter of those with a genuine allergy had a current epinephrine prescription, a potentially life-saving drug.
“We must improve efforts to educate on the importance of carrying epinephrine auto-injectors for anyone with a diagnosed food allergy, as this medication is the first-line treatment for anaphylaxis, a serious allergic reaction that can be life-threatening,” said Gable.
Any food can theoretically cause an allergic reaction, but which food is the worst culprit for causing food allergies?
“Our data show that shellfish is the top food allergen in adults, that shellfish allergy commonly begins in adulthood, and that this allergy is remarkably common across the lifespan. We need more studies to clarify why shellfish allergy appears to be so common and persistent among U.S. adults,” said Gupta.
The study showed that 7.2million U.S. adults have a shellfish allergy, making it a more common allergen than milk (4.7million adults) and peanuts (4.5million adults). The study also found that of adults who were allergic to one or more foods, half of them had developed at least one of their food allergies as an adult.
“We were surprised to find that adult-onset food allergies were so common. More research is needed to understand why this is occurring and how we might prevent it,” said Gupta.
This counteracts the commonly-held belief that most allergies develop in childhood. It should also be noted that although the study included a large number of participants, the data was collected from people who self-reported the information, meaning it might not entirely be accurate. Nevertheless, it puts the real issue of adult-onset allergies in the spotlight and also indicates the importance of getting food allergies diagnosed by a professional, to stop people needlessly cutting out particular foods from their diet without genuine allergies.
“This study signals that food allergy among adults is a more significant issue in the U.S. than previously thought, particularly the emerging health problem of adults developing their food allergies later in life, even after regularly eating foods that were previously harmless,” said Gable.