Food Allergy Affects Nearly 3 Percent of Americans
The number of people who experience true food allergy has been a topic of much debate over the years, with as many as 30 percent of Americans believing that they do. Now a new study by investigators at Johns Hopkins Children’s Center, the National Institutes of Health, and other institutions report that an estimated 2.5 percent of children and adults in the United States have at least one food allergy.
Food allergy is most common in children younger than 5 years
Food allergy occurs when a person’s immune system mistakenly attacks a food protein. (This is not the same as food intolerance, which affects many more people than does food allergy.) When people with food allergy eat one or more certain foods, it triggers the release of histamine and other chemicals that result in an allergic reaction. The Food Allergy & Anaphylaxis Network (FAAN) reports that symptoms of food allergy may be mild (e.g., rash, hives, itching, swelling) or severe (difficulty breathing, loss of consciousness, wheezing, etc.), and even fatal.
Results of the new study are based on blood levels of antibodies obtained from blood samples and interview data gathered from more than 8,200 individuals ages 1 to 60 years and older. The study, which is believed to be the largest food allergy investigation to date, looked for the prevalence of allergy to four different foods and links between food allergies and asthma, eczema, and hay fever.
Researchers found that 2.5 percent of participants had blood test results that indicated a food allergy. At the top of the list was an allergy to peanuts, which affected 1.5 percent of subjects. Shrimp (1%), eggs (0.4%), and milk (0.2%) completed the list. This study did not test for allergies to other foods frequently cited as culprits, including tree nuts, fish, wheat, and soy. The FAAN notes that eight foods (four in the study and four not evaluated) account for 90 percent of all food-allergic reactions.
Test results also revealed that
- 1.3 percent of subjects had more than one type of allergy
- Children younger than 5 years were most likely to have a food allergy (4.2%), and they were also more than twice as likely as people older than 20 to have a food allergy
- Food allergy among people ages 6 to 19 years was 3.8 percent
- Blacks were three times more likely as white to have food allergy
- Black boys were more than four times as likely as white women older than 20 to have a food allergy
- Men were nearly twice as likely as women to have food allergy
- Individuals with asthma had nearly a fourfold risk of having a food allergy than people without asthma
- Researchers did not find an especially strong link between having food allergy and being diagnosed with hay fever or eczema
The study’s senior investigator, Darryl Zeldin, MD, acting clinical director at the National Institute of Environmental Health Sciences, noted that “this study is comprehensive in its scope and is the first to use specific blood serum levels and look at food allergies across the whole life spectrum.” The study only used individuals who had blood levels of antibodies that were high enough to suggest a clinical disease.
This new study sheds fresh light on food allergy among Americans. Investigator Robert Wood, MD, director of Allergy and Immunology at Hopkins Children’s noted that “our findings confirm a long-suspected interplay between food allergies and asthma, and that people with one of the conditions are at higher risk for the other.”
Johns Hopkins Children's Center
Food Allergy and Anaphylaxis Network