Food allergies are common but not nearly as widespread as people may believe.
The Food and Drug Administration (FDA) name eight common allergenic foods recognized by law: milk, eggs, fish, shellfish, tree nuts (which include walnuts), peanuts, wheat, and soybean.
The FDA have estimated that these foods and their derivates are responsible for around 90 percent of all allergic reactions.
In anaphylaxis, the human body overreacts to allergenic substances. It causes extreme symptoms in different parts of the body, all at the same time. A person who is experiencing anaphylaxis always requires immediate medical attention.
However, although millions of people do live with food allergies, many more mistakenly believe that they have an allergy. In reality, these people are unlikely to come to any harm.
This is the conclusion of a recent study conducted by researchers from Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University in Evanston, both in Illinois.
The findings, which appear in the journal JAMA Network Open, suggest that almost 1 in 5 adults in the United States think that they have a food allergy, while only about 1 in 10 actually do.
19 percent of adults believe they are allergic
The research team — led by Dr. Ruchi Gupta — analyzed data derived from a representative survey that collected information from more than 40,000 adults based in the U.S.
An estimated 26 million, or over 10 percent, of U.S. adults do have a food allergy, but Dr. Gupta and colleagues found that around 19 percent of U.S. adults believe that they are allergic to certain foods.
However, their beliefs seem to be mistaken; the symptoms they report do not point in the direction of food allergies.
"While we found that 1 in 10 adults have [a] food allergy, nearly twice as many adults think that they are allergic to foods, while their symptoms may suggest food intolerance or other food-related conditions," explains Dr. Gupta.
Many people, she suggests, may begin to fear that they are allergic when their reactions are, in fact, due to other conditions.
"It is important to see a physician for appropriate testing and diagnosis before completely eliminating foods from the diet," says Dr. Gupta, adding:
"If food allergy is confirmed, understanding the management is also critical, including recognizing symptoms of anaphylaxis and how and when to use epinephrine."
Dr. Ruchi Gupta
The most common allergies among adults
Of all survey respondents, even among those who reported symptoms that seemed consistent with a food allergy, specialists had only diagnosed allergies in around half of them.
Also, among people with clinically diagnosed food allergies, under 25 percent held a prescription for epinephrine, which people use to treat severe allergic reactions.
Another interesting finding of the study is that almost half of the adults with food allergies had developed at least one of their allergies in adulthood.
"We were surprised to find that adult-onset food allergies were so common. More research is needed to understand why this is occurring and how we might prevent it," says Dr. Gupta.
When they looked at the specifics of food allergies among U.S. adults, the researchers found that the most common ones were:
- shellfish (7.2 million)
- milk (4.7 million)
- peanuts (4.5 million)
- tree nuts (3 million)
- fin fish (2.2 million)
- eggs (2 million)
- wheat (2 million)
- soy (1.5 million)
- sesame (0.5 million)
"Our data show," explains Dr. Gupta, "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."
Still, it remains unclear as to why so many adults are allergic to shellfish, and how to prevent the development of this allergy.
"We need more studies to clarify why shellfish allergy appears to be so common and persistent among U.S. adults," Dr. Gupta concludes.