By Carol A. Kemper, MD, FACP

Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center

Dr. Kemper reports no financial relationships relevant to this field of study.

SOURCE: Gupta RS, Warren CM, Smith BM, et al. Prevalence and severity of food allergies among US adults. JAMA Netw Open 2019;2:e185630.

Are 19% of American adults really allergic to a food? This survey, conducted by the nonpartisan and objective research organization NORC at the University of Chicago from 2015 to 2016, is an extension of a national survey of food allergies conducted in children from 2009 to 2010. The primary outcome measure was the prevalence and severity of a convincing food allergy, based on the presence of at least one symptom on a stringent symptom list in adults in the United States. Food intolerance or symptoms not included in the expert panel’s list of stringent symptoms were excluded. The survey was completed by 40,443 adults, with a mean age of 46.6 years.

Remarkably, 19% of adults reported at least one convincing or nonconvincing food allergy. Among adults with a convincing food allergy, nearly half (48%) reported developing at least one food allergy in adulthood, whereas the other half developed their allergy before 18 years of age. Slightly more than half (51%) reported “severe” food allergies, and 45% reported allergies to multiple foods. One-third reported at least one food allergy-related ED visit in their lifetime. Roughly half were told by a physician that they had a food allergy, and one-fourth had filled a prescription for epinephrine at some point.

Women were nearly twice as likely as men to have current food allergies, and twice as likely to have developed a food allergy as an adult. The most common allergies were to shellfish (2.8%), milk (1.9%), peanuts (1.8%), tree nuts (1.2%), and fin fish (0.9%). The prevalence of food allergies did not appear to differ significantly between ethnicities, regions of residence in the United States, or household income.

Interestingly, earlier data suggested that approximately 10.8% of adults would report a food allergy. This would correspond to approximately 26 million adults. Yet, this survey suggests that nearly twice as many people believe they have a food allergy to at least one food, and one-third of them have visited an ED for an allergic reaction to food. That is a lot of ED visits.

There is much to learn about the frequency and consequences of food allergies in adults, which are more common than previously believed. Or, at least a lot of people think they have a food allergy. The obvious question is whether all these people have true food allergies, or just think they do or, worse, were convinced by a physician that their symptoms are the result of a food allergy, and they are unnecessarily restricting their diet.