Dr. Ruchi Gupta, lead author of the study and professor of pediatrics at Northwestern University Feinberg School of Medicine, commented, "While we found that one in 10 adults have food allergy, almost twice as many adults think that they are allergic to foods, while their symptoms may suggest food intolerance or other food related conditions". These results suggest that 26 million US adults have a convincing food allergy but nearly 50 million think they do.
"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.
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.
The survey - answered by 40,000 people in the U.S. - also asked participants what they thought might have triggered the adult onset of an allergy, though the responses have not yet been analyzed.
4, said that 19 percent of adults think they are food allergic, compared to the 10 percent of those who actually have a diagnososed allergy, which is over 26 million people in the country. The most common foods causing allergies in these adults were shellfish, milk, peanuts, tree nuts, and fin fish.
"Our data show that shellfish is the top food allergen in adults, that shellfish allergy commonly begins in adulthood, and that this allergy is remarkably common across the lifespan", Gupta said. "That's a big number".
But researchers also found many adults believe they are allergic to foods when they're instead more likely suffering from food intolerance or a health condition. "There was definitely a need for a study like this. This is double that". The researchers found that many people with an allergy do not have a prescription for potentially life-saving medication, while others might be avoiding foods unnecessarily. "I think this will give a lot of people pause", said Reisacher, who was not affiliated with the new research.
According to the US Centers for Disease Control and Prevention, between 4% and 6% of American children are affected by food allergies.
"If they only had, say, bloating or stomach pain or diarrhoea then we took them out because that could be a lactose intolerance or a food intolerance", said Gupta. "A food allergy and intolerance can have numerous same symptoms".
She and her team were surprised that so many adults had allergies.
Allergies develop when your immune system mistakenly identifies a substance such as pollen, mold, animal dander, or food as harmful.
About one in four of those that have a food allergy developed it in adulthood, the survey, published in JAMA Network Open found.
"This is a very welcome addition to the literature to understand how many adults are affected by food allergy and nuances of severity and risk", he said. "That's a lot of people on unnecessary elimination diets that could have consequences in terms of cost, worry and nutritional impact". "I've just noticed in the past few years, it really is helping everyone else with food allergies, the number of restaurants, airlines, just being aware of that and accommodating has made it much easier for people", he said.