Sesame allergy is one of the ten most common childhood food allergies. Reactions to sesame can be severe among children with the allergy. Only an estimated 20% to 30% of children with sesame allergy outgrow it. The Food and Drug Administration is currently considering whether to include sesame in the list of allergens that must be disclosed on food labels. Currently, Europe, Australia, and Canada do so.

Diagnosing sesame allergy has been challenging. Standard allergy tests—skin prick tests and blood tests of sesame antibody levels—have yielded inconsistent results in past studies. These studies have often included only children who were already suspected of having sesame allergy.

Researchers from NIH’s National Institute of Allergy and Infectious Diseases (NIAID), led by Dr. Pamela A. Frischmeyer-Guerrerio, set out to determine how common sesame allergy is among U.S. children with other food allergies. They also asked whether sesame antibody tests could reliably predict allergic reactions to the seeds.

The research was funded by NIAID and NIH’s National Cancer Institute (NCI). Findings were published on October 28, 2019, in Pediatric Allergy and Immunology.

The research team enrolled 119 children with documented food allergies. Some had recently had an allergic reaction to sesame or were known to tolerate sesame products, such as tahini or hummus, in their diet. Those whose allergic status to sesame was unknown were offered an oral food challenge, considered the gold standard for diagnosing food allergy. This involves eating gradually increasing amounts of sesame under medical supervision and seeing if an allergic reaction occurs.

Overall, 17% of the 88 children whose allergic status could be confirmed had a sesame allergy. The children with sesame allergy often had peanut and tree nut allergies as well.

The scientists then measured the amount of an antibody called sesame-specific immunoglobulin E (sIgE) in the blood of these 88 children. People with a food allergy will produce immunoglobulin E in response to the allergen.

Using this information, the researchers developed a mathematical model for predicting the probability that a child with a food allergy is allergic to sesame. They were able to identify a threshold of sIgE over which a child has a greater than 50% chance of being allergic to sesame. While more tests will be needed to validate this model, it’s a promising step in diagnosing sesame allergy.

“It has been a challenge for clinicians and parents to determine if a child is truly allergic to sesame,” says NIAID Director Dr. Anthony S. Fauci. “Given how frequently sesame allergy occurs among children who are allergic to other foods, it is important to use caution to the extent possible when exposing these children to sesame.”

Food allergies are the leading cause of anaphylaxis, a sudden, severe and potentially life-threatening allergic reaction. Anaphylaxis can be caused by food allergies, insect stings, or medications. Symptoms of food allergies typically appear from within minutes or up to 2 hours after a person has eaten the food to which they are allergic.

Allergic reactions can include:

• hives,
• flushed skin or rash,
• tingling or itchy sensation in the mouth,
• face, tongue, or lip swelling,
• vomiting and/or diarrhea,
• abdominal cramps,
• coughing or wheezing,
• dizziness and/or lightheadedness,
• swelling of the throat and vocal cords,
• difficulty breathing and
• drop in blood pressure.

If you or someone in your household is allergic to sesame, an important change is taking place to help you quickly identify foods that contain sesame. As of January 1, 2023, sesame is required to be labeled as an allergen on packaged foods, including dietary supplements.

Sesame joins eight other foods already declared as major food allergens by federal law. The nine major food allergens are: 

• milk
• eggs
• fish, such as bass, flounder, cod
• Crustacean shellfish, such as crab, lobster, shrimp
• tree nuts, such as almonds, walnuts, pecans
• peanuts
• wheat
• soybeans
• sesame

Be Careful During the Sesame Labeling Transition Period

Even though the requirement that sesame be listed on the label as an allergen is in effect as of January 1, 2023, you still may find food products for sale that don’t list sesame as an allergen on the label. 

The law establishing this sesame labeling does not require food products that were already on their way to the store or in stock before 2023 to list sesame as an allergen on the label. Therefore, these food products do not need to be removed from the marketplace or relabeled to declare sesame as an allergen. 

Because some packaged foods can have a long shelf life, it’s hard to say when pre-2023 stock will be replaced with food products carrying the required labels. So, proceed with caution during this transition period. 

Also keep in mind a food product’s ingredients can be changed at any time, so it’s a good idea to check the label every time you buy the food product – even if you have eaten it before and didn’t have an allergic reaction.

If you want to know more about the use of sesame in a food product, the U.S. Food and Drug Administration, which is responsible for enforcing the labeling requirements, recommends you contact the manufacturer or distributor identified on the food product label.

Examples of New Sesame Labeling

Here is what the new sesame labeling might look like.

The name of the food source of a major food allergen must appear either:

In parentheses following the name of the ingredient.
Examples: “lecithin (soy),” “flour (wheat), natural flavor (sesame),” and “spices (sesame)”

— OR —

Immediately after or next to the list of ingredients in a “Contains” statement.
Example: “Contains sesame.”

Sesame has always been required to be listed in the ingredient statement if it was an added ingredient, with a few exceptions. That’s true for any added ingredient. Now that sesame is a major food allergen, the FDA expects that it be specifically listed as sesame on the label if it’s part of another ingredient, like “natural flavor,” or “spice mix.”

Additionally, if a food package has a “Contains” statement and has sesame as an ingredient, sesame will now have to be included in that “Contains” statement. As a result, consumers will have more information about which products contain sesame as an ingredient.

The sesame labeling requirements apply to packaged foods. Allergen labeling requirements for foods that aren’t packaged may vary, like bagels in a grocery bin or bakery goods displayed on trays. If you’re concerned about those products, you may want to ask store personnel for food allergen information.

Why Did Sesame Become a Major Food Allergen?

Sesame became the ninth major food allergen through the Food Allergy Safety, Treatment, Education, and Research (FASTER) Act, a federal law passed in 2021. The other eight major food allergens were defined through a federal law passed in 2004.

While many kinds of foods can cause allergies, the federal laws focus on the most common ones and require that food labels identify the food source of a major food allergen using its common or usual name on the label.

The nine major food allergens cause the majority of serious food allergic reactions in the U.S.