A survey of over 40,000 adults suggests that food allergies are common and severe among American adults and often start in adulthood. Findings highlight the importance of appropriate confirmatory testing for food intolerances and allergies as well as thorough patient counseling.

In published studies, food allergies have been shown to be costly and potentially life-threatening conditions that often have adverse effects on patients’ well-being. “Many studies have analyzed the prevalence of food allergies in children in the United States, but less is known about their burden among adults,” says Ruchi S. Gupta, MD, MPH. Some children with food allergies develop natural tolerance whereas others retain their allergy as they enter adulthood. Adults can also develop new food allergies, and evidence suggests that certain types are more likely to develop during adulthood. “We need to learn more about adult food allergies, including their frequency, timing of onset, allergen type, and severity as well as potential predictors of their development and/or resolution.” adds Dr. Gupta.

 

A Spotlight on Adults

For a study published in JAMA, Dr. Gupta and colleagues collected nationally representative estimates of the distribution, severity, and key factors associated with adult food allergies. A cross-sectional survey was administered to more than 40,000 US adults. According to the results, 10.8% of adults—equating to more than 26 million people—had at least one convincing food allergy. However, 19.0% of adults surveyed believed they were food allergic, per self-reports.

Among US adults, the most common allergies identified in the study were shellfish, milk, peanut, tree nut, and fin fish (Table). Food allergy rates were significantly higher among non-white adults, even after adjusting for income, educational level, numerous physician-diagnosed atopic conditions, and other factors. Among food-allergic adults, the researchers found that:

  • 1% experienced a severe food allergy reaction.
  • 3% was allergic to multiple foods.
  • 0% developed at least one new food allergy as an adult.

“Adult-onset food allergies were common across a wide range of ages and allergens,” explains Dr. Gupta. “In addition, only about half of adults with a convincing food allergy had actually been diagnosed with the condition by their physician. Another key finding was that 26.9% developed a convincing food allergy only during adulthood, and 52.0% developed one only before the age of 18.”

After extrapolating the data, at least 13 million food-allergic adults were found to have experienced at least one severe food-allergic reaction. Regarding healthcare utilization, only 24.0% of participants—at least 10 million people—reported having a current epinephrine prescription, and 38.3%—at least 12 million people—reported having at least one food allergy–related ED visit at some point in their life. “When we think about these data collectively, it’s clear that food allergies are an important emerging health problem among adults,” Dr. Gupta says.

 

Taking the Next Step

Considering the challenges associated with avoiding common foods in the diet and other food allergy management behaviors, Dr. Gupta says clinicians should help ensure that those with suspected food allergies receive appropriate confirmatory testing and counseling. “Greater patient education efforts are needed to help adults understand key differences between food related conditions like food intolerances and allergies,” she says. “They need to be encouraged to see their physician to receive a proper diagnosis. If they are diagnosed with a food allergy, ensure that they’re prepared with a management plan and appropriate epinephrine prescriptions if necessary.”

Dr. Gupta notes that future investigations should further explore the causes of food allergies in adults. “For example, our data showed that women were at higher risk of developing adult-onset food allergies than men,” she says. “We need to determine if hormonal changes like pregnancy or other factors like infections, diets, or changes in environment play a role in the development of allergies as people age. Efforts are also needed to determine why allergens like shellfish are more common in adults. The hope is this information will help guide us in our efforts to prevent and/or treat adults with food allergies in the future.”

 

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