(Reuters Health) - More than 10 percent of American adults are allergic to at least one food, a new study suggests.

Among more than 40,000 adults surveyed, 10.8 percent reported the kinds of severe symptoms that are consistent with a food allergy, and another 8.2 percent said they believed they had food allergies, but their symptoms suggested other causes, according to the report in JAMA Network Open.

“The main message from the survey is that one in five adults have some kind of food related conditions that are causing them to avoid certain foods,” said Dr. Ruchi Gupta of Northwestern University’s Feinberg School of Medicine and the Ann & Robert H. Lurie Children’s Hospital of Chicago. “And one in 10 has what looks convincingly like a food allergy - and of those, only half are getting a proper diagnosis by a physician.”

To take a closer look at food allergies in adults, Gupta and her colleagues turned to two internet-based panels of people who have agreed to fill out surveys for a small remuneration: the AmeriSpeak panel and a panel put together by SSI Dynamix, a market research company. All told, 40,433 US adults completed the food allergy survey, for which they received $5 each.

Those deemed to have a food allergy had least one convincing food allergy symptom, which meant a severe reaction involving the skin or oral mucosa, gastrointestinal tract, cardiovascular or respiratory tract.

People who didn’t have these reactions were assumed to have a food intolerance, such as celiac disease or lactose intolerance, or a non-allergy mediated reaction in the mouth.

Among those who were determined to have a food allergy, 48 percent reported developing at least one of their allergies in adulthood, while 26.9 percent developed food allergies only in adulthood. The most common foods causing allergies in these adults were shellfish, milk, peanuts, tree nuts, and fin fish.

Fewer than a half of the people with food allergies, 47.5 percent, said they had gotten a diagnosis from a physician, 38.3 percent reported they had been to the emergency room for a life-threatening reaction, while fewer than one quarter, 24 percent, said they had a prescription for epinephrine to be used in case of a severe reaction.

While Gupta had occasionally heard adults saying they used to be able to eat a food like shellfish, but had to give it up because of severe reactions, she was most surprised that among those with food allergies, “almost half reported developing at least one food allergy as an adult. That’s a big number.”

Food allergies haven’t been studied much in adults, so “I think this is a really important article,” said Dr. William Reisacher, director of allergy services at NewYork-Presbyterian/Weill Cornell Medicine in New York City. “There was definitely a need for a study like this. The results are very compelling. It was thought that maybe four to five percent of adults had food allergies. This is double that.”

Reisacher was also surprised at how many people had developed food allergies in adulthood. “I think this will give a lot of people pause,” said Reisacher, who was not affiliated with the new research. “It makes you wonder what is happening in adults causing all these allergies.”

The fact that fewer than a quarter of those with food allergies had a prescription for an EpiPen to deal with life-threatening reactions is concerning, Reisacher said. “One of the most common places for accidental exposure is restaurants,” he said. “The majority of people who die from food allergy are actually aware of what they are allergic to.”

The new study “points to the fact that this is not something that receives a lot of attention and it needs to receive more attention,” said Dr. Corinne Keet, an allergy specialist at the Johns Hopkins Children’s Center in Baltimore. “We think of food allergies as a childhood disease and clearly there are a lot of adults who have food allergies and their management and treatment may be different from children’s.”

“What’s also important is the number of adults--and children--who think they have food allergies and don’t,” said Keet, who was not involved in the new study. “Almost half of the people who thought they had food allergies in this study did not. That’s a lot of people on unnecessary elimination diets that could have consequences in terms of cost, worry and nutritional impact.”

Keet wasn’t surprised that few people had an EpiPen prescription. “They think they are not at risk if they follow a restriction diet,” she said. “And EpiPens are expensive and you need a doctor prescription every year. So I’m not surprised they don’t have them, even though they should.”

SOURCE: bit.ly/2RBJYiU JAMA Network Open, online January 4, 2019.