Study: 26 million American adults may be food allergic

At least 10.8 percent of adults in the United States—which works out to more than 26 million individuals—are food allergic, though almost twice as many—19 percent—believe they have a food allergy, according to a study published recently on JAMA Network.

“[Our] data suggest that there are currently at least 13 million food-allergic adults who have experienced at least 1 severe food-allergic reaction, at least 10 million adults who have received food allergy treatment in the [emergency room], and at least 12 million adults with adult-onset food allergy,” the study authors summarized.

The research, which examined responses from 40,443 individuals aged 18 or older from around the country, also found that the most common food-related allergies were to shellfish (2.9% of all adults), milk (1.9%), peanuts (1.8%), tree nuts (1.2%) and fin fish (0.9%).

Among food-allergic adults responding to the survey…

• 51.1% reported that they had experienced a severe food allergy reaction;

• 38.3% reported at least one food allergy–related lifetime emergency department visit;

• 24% reported a current epinephrine prescription;

• 45.3% said they were allergic to multiple foods; and

• 48% reported developing food allergies as an adult.

To distinguish between individuals merely claiming to have a food allergy and those with convincing evidence, the study considered reported food allergies to be convincing only if the most severe reported reaction included at least one symptom that also appeared on a “stringent symptom list” developed by an expert panel brought together expressly for the purposes of the study. Hence the variance between the 19 percent self-reporting food allergies and the 10.8 percent that were deemed by the study to have “convincing food allergy prevalence.”

In the discussion of their findings the study authors warn that their data may signal a growing trend.

“Given that the most prevalent allergies observed were shellfish and peanut, which prior pediatric work suggests are infrequently outgrown, this finding suggests that the population-level burden of food allergy is likely to increase in the future, absent widespread implementation of effective prevention efforts and/or therapies,” they say, later adding that “[a]dult-onset food allergies are an important emerging health problem. A recent analysis of electronic health record data collected from a network of Chicago-area clinics concluded that although shellfish, tree nut, and fin fish allergies were the most common adult-onset food allergies, it appears to be possible to develop adult-onset food allergies to all major food allergen groups. In the current study, adult-onset allergies were observed to every assessed food.”

“These data suggest that at least 1 in 10 US adults are food allergic,” the authors summarize. “However, they also suggest that nearly 1 in 5 adults believe themselves to be food allergic, whereas only 1 in 20 are estimated to have a physician-diagnosed food allergy. Overall, approximately half of all food-allergic adults developed at least 1 adult-onset allergy, suggesting that adult-onset allergy is common in the United States among adults of all ages, to a wide variety of allergens, and among adults with and without additional, childhood-onset allergies.”

The study was led by Ruchi S. Gupta, MD, MPH, a professor of pediatrics at Northwestern University Feinberg School of Medicine, and also included Christopher M. Warren, BA; Bridget M. Smith, PhD; Jialing Jiang, BA; Jesse A. Blumenstock, BS; Matthew M. Davis, MD, MAPP; Robert P. Schleimer, PhD; and Kari C. Nadeau, MD, PhD. Surveys were administered via the internet and telephone from October 9, 2015, to September 18, 2016.