It’s common to become allergic to a food item as an adult

Dr. Ruchi Gupta is the director of the Center for Food Allergy & Asthma Research at Northwestern University. Her center's research suggests that nearly 11% of U.S. adults are allergic to at least one kind of food. (Anne Snabes/MEDILL)

By Anne Snabes
Medill Reports

Nearly 11% of adults in the U.S. are allergic to at least one type of food, according to Northwestern University research published last year. The researchers found that almost half of adults with food allergies acquired at least one allergy during adulthood.

Ruchi Gupta, a pediatrician and director of the Center for Food Allergy & Asthma Research at Northwestern, said that among those who acquired allergies during adulthood, half already had an allergy from childhood and developed an additional one as adults. The other half developed an allergy for the first time as adults.

“Which is really interesting — like, never having anything and then developing their first one as an adult,” she said.

Food allergies to peanuts, shellfish and milk are among the most prevalent for adults.

Gupta and her colleagues’ research suggests that it is common to acquire an allergy as an adult. She told the Medill News Service that only 5% of adults have an allergy that was diagnosed by a physician, and another 5% of adults recognize symptoms of an allergy that has not been diagnosed, suggesting that some do not see a physician for their food allergy. The fact that adult allergies are common is especially pertinent now, as it’s hard for people with allergies to find food they can eat in grocery stores during the coronavirus pandemic, the New York Times reports.

Now, people sometimes have to buy brands of a product that they do not typically purchase because their go-to brands are sold out, so make sure to check the ingredients of the new brand to ensure that it does not contain a food item you are allergic to.

Gupta is concerned that people with food allergies won’t be able to access food that is safe for them. She talked to the Greater Chicago Food Depository, where contacts told her that there are more people who need food now than normal. The food bank is preparing boxes for local residents.

“The concern is, as they’re working so hard to put these food boxes together just to get food to people, what’s going to happen to people that have food allergies or other food conditions?” she said. “Are they going to be able to get the foods they need to stay safe and have food?”

In their study, Gupta and her colleagues surveyed more than 40,400 adults in the U.S. They published their results in the digital journal JAMA Network Open on January 4, 2019. Jialing Jiang, a research study coordinator at the center, said a panel of food allergy experts determined criteria that would differentiate an allergy from another food condition. Some participants may have thought they had an allergy when they in fact had an intolerance or oral allergy syndrome.

The researchers found that one in five adults think they have a food allergy, while only one in 10 actually do, Gupta said. A food intolerance or other food condition is treated differently than an allergy. People with lactose intolerance can drink specific milks that contain the enzyme lactase, while people with a milk allergy can’t consume milk at all and have to carry epinephrine with them, according to Gupta. Like children, adults with allergies can undergo anaphylactic shock, which could be life-threatening, according to the Mayo Clinic.

“See an allergist and figure out what you have, because there’s so many food-related conditions and some are treatable,” Gupta recommended for adults. “You really want to make sure what your condition is so that you can treat it properly and potentially not have to avoid so many different important food items.”

She said developing a food allergy in adulthood affects people’s lives “so much,” because “food is everywhere.”

“It’s kind of a part of everything we do in our culture,” she explained. “Anytime you socialize, there’s usually food around, and so avoiding food is very challenging.”

The study found that the most common allergy for U.S. adults is shellfish.

“I hear stories about that all the time: ‘Yeah, I used to be able to eat it just fine and then I ate it and had this horrible reaction,’” she said.

Gupta said it isn’t known how people develop allergies, but there are many possible theories. One theory suggests that we’re becoming too clean and are not being exposed to dirt, which contains bacteria. People are also using antibacterial cleansers, which can kill both bad and good bacteria on our bodies. People may be less exposed to a good microbiome, which could cause the immune system to fight substances it shouldn’t, such as foods, Gupta said.

Many families are now staying inside due to the COVID-19 pandemic.

“It’s going to be interesting what COVID does … to these infants that are having to be inside and having to be clean,” she said. “Are we going to see increases in allergies in general or not? It’s kind of a natural experiment right now.”

When looking at adults, Gupta considers what has changed in their lives that may have caused them to develop an allergy. In the study, she and her colleagues asked the participants questions such as if they had moved to a new place or if they had an infection around the time that they developed an allergy. Gupta said her team is trying to find factors that people think may have triggered their food allergy. She and her colleagues still have to analyze the results of the questions.

Gupta plans to write a paper that focuses on adults who have acquired food allergies and the factors associated with their development of allergies. She said her study opened up “a lot” more questions.

“A lot more research needs to be done in adults,” Gupta said.

Photo at top: Ruchi Gupta is the director of the Center for Food Allergy & Asthma Research at Northwestern University. Her center’s research suggests that nearly 11% of U.S. adults are allergic to at least one kind of food. (Anne Snabes/MEDILL)