Food Allergies: 5 Myths Debunked How to tell a food allergy from an intolerance or sensitivity — and what to do about it.

Nearly a third of people living in the U.S. believe they have a food allergy, according to a recent study published in The Journal of the American Medical Association . But only 5% of children and 4% of teens and adults have true food allergies.

Why do many people think they have a food allergy when they don’t?

Experts say it’s because people don’t understand what really constitutes a food allergy and they often misuse the term.

“Unfortunately, the term ‘allergy’ is sometimes used by the public or health care providers to describe any unpleasant experience patients have with eating food, including ‘feeling bad,’” says Marc Riedl, MD, MS. He worked on the study in The Journal of the American Medical Association and is an assistant professor of medicine at the University of California at Los Angeles David Geffen School of Medicine.

Linking ‘food allergy’ with ‘feeling bad’ causes confusion, and can lead to people cutting out certain foods thinking they’re allergic to them, when instead they may be missing out on delicious foods or risking nutritional deficiencies.

The National Institute of Allergy and Infectious Diseases, which funded the study, has released new guidelines about definition, diagnosis, and management of food allergies.

Myth: I’m allergic to foods that don’t agree with me.

Not necessarily.  A food allergy is a very specific  immune system response involving either the immunoglobulin E (IgE) antibody or T-cells. Both are immune system cells that react to a particular food protein, such as milk protein.

An IgE reaction occurs within minutes to an hour or so of either smelling, touching, or ingesting a particular food. The presence of the food triggers the immune system to over-react and interpret the food as harmful. Histamine is released, causing symptoms that range from mild to severe, including hives, itching, trouble breathing, wheezing, and anaphylaxis.

About 30,000 Americans per year go to the emergency room due to severe allergic reactions to food, and as many as 200 die every year from food allergies, according to the Food Allergy and Anaphylaxis Network.

A non-IgE immune system reaction can occur within three to four hours of ingestion and can often be mistaken for food insensitivity or food poisoning, explains Wesley Burks, MD, division chief of pediatric allergy and immunology at Duke University Medical Center in Durham, N.C.

“The biggest misunderstanding is that there are different types of food allergies, they’re reproducible, the reactions are the same,” Burks says. “You can’t eat cheese, feel sick, and claim a food allergy, but then turn around and enjoy ice cream and feel OK. With a true food allergy, the trigger does not change and the trigger will always set off the same immune system response.”

Not true. And neither are the same as food allergy.

Experts say “food intolerance” and “food sensitivity” are often used interchangeably by the public, causing misunderstanding. Add “food poisoning” to the list and people become even more confused.

• Food intolerance occurs when the body lacks a particular enzyme to digest that food. Two common examples are lactose intolerance and celiac disease, an autoimmune disorder in which the gastrointestinal tract cannot process gluten, a protein in wheat-based products such as cereal and bread.  An intolerant person avoids the foods that trigger a reaction, but these reactions aren’t caused by the immune system and they are not life threatening.
• Food sensitivity, an understudied area, generally means people have an unpleasant reaction to certain foods; perhaps they develop acid reflux, nausea, or abdominal cramps, but again, these are not immune system reactions, and these reactions do not always occur in the same way when eating the food.

You could also have a bad reaction to food tainted by bacterial contamination or not properly prepared. That’s food poisoning. Symptoms often involve diarrhea and vomiting and typically clear up in 24-48 hours.

Myth: If I think I have a food allergy, I should just avoid the offending food.

Reality: If you suspect you have a food allergy, just skipping the food that irritates you isn’t enough.

“There are two major problems with this approach,” Riedl says. “Unintentional food exposures occur, even in the most cautious individuals with true food allergy. The ‘self-diagnosed’ patient is unlikely to be properly prepared to manage this potentially life-threatening reaction, such as use of an Epi-Pen.” Epi-pen and Twinject are injectable forms of epinephrine.

Proper diagnosis, Riedl says, enables patients to understand how best to manage the allergy and eliminates the anxiety, inconvenience, and expense of going at great lengths to avoid foods that do not cause allergies.

More research is also needed to better understand if food allergies can be predicted, particularly during childhood, and why some people outgrow certain food allergies. Insights to both of these issues could help improve prevention and treatment of food allergies.

Fleischer agrees there has been a great deal of undue anxiety around food and food allergies. “Food allergies are definitely being overdiagnosed,” he says. “People are looking for answers to some of their problems and they’re blaming food because food is easy.”

Myth: I only need a blood test to diagnose a food allergy.

Blood tests can also help diagnose a true food allergy by measuring IgE levels and determine whether there’s a true food allergy. However, the new guidelines recommend against the routine use of these tests and making a food allergy diagnosis based on them alone.

Fleischer warns that blood tests can produce false-positives — results that indicate an allergy when there isn’t one — in patients who have eczema, asthma, or other types of allergies because those people already have higher-than-average IgE levels.

Myth: I only need a blood test to diagnose a food allergy. continued…

One accurate way to find out if you have a true food allergy is to visit your doctor and undergo a food challenge, says David Fleischer, MD, a pediatric allergist at National Jewish Health in Denver.

The food challenge is managed by the doctor and done in a controlled environment at the doctor’s office. It involves gradually giving higher doses of a particular food to see how much of that food is needed to trigger an immune system response.

Another type of test — the skin prick test — can also indicate if the patient has a real food allergy by injecting a small amount of the allergen into the skin and checking whether the skin develops a bump or a rash. Again, an allergy diagnosis should not be made on a skin test alone.

Food elimination diets — taking away one or a few specific foods to see if the reaction disappears — may help.

 

 

Myth: I can easily tell which foods trigger my allergies.

Reality: You might need to do more work than you think to spot all your trigger ingredients.

The 2004 Food Allergen Labeling and Consumer Protection Act made it easier to read food labels and quickly determine what’s safe to eat and what isn’t. The federal law requires warnings written in plain English for the eight most threatening food allergens: wheat, soy, milk, peanut, tree nut, shellfish, fish, and egg.

However, there is still risk, because a manufacturer “cannot ensure 100% that there are not traces of the food allergen in their product,” Burks says.

Manufacturers are not federally required to report food allergens beyond the main eight, which could pose risks to your health if you’re allergic to something other than the ones covered by the 2004 law.

The 2004 law also doesn’t require manufacturers to declare allergenic ingredients introduced through cross-contact, such as cooking a food in peanut oil or eating food cut with the same utensils that were used to prepare fish. The FDA is working on ways to standardize food labeling so that they are more uniform and even clearer for consumers.

Restaurants  also pose a risk for people with food allergies, Fleischer says. “People really have to be careful. Even small traces can cause severe reactions” in people who are highly allergic to those triggers.