Knowing which packaged foods contain various seeds has largely been a guessing game, but a new law enacted in January 2023 changes that.
A new rule that requires foods containing sesame seeds to be clearly labeled follows data from a 2020 study that highlighted the link between sesame seed allergies and other food allergies.2 Sesame is not the only seed that can trigger reactions, however, and it is possible this law could spur conversations about other types of seed allergies.
Millions of people in the United States have food allergies. The top allergens that have been recognized—and flagged on ingredients lists—include peanuts, tree nuts, soybeans, cow’s milk, eggs, shellfish, fish, and wheat.3
Seeds traditionally have not made the cut for labeling requirements, but the 2020 research highlighted several findings on seed allergies. According to the data, 17% of children who were allergic to at least 1 type of food were also allergic to sesame seeds.2 Many of these children were also allergic to tree nuts and peanuts, or other types of seeds, but overall, the presence of specific antibodies increased the risk of having allergies to sesame seeds. As many as one-third of the children included in the study eventually outgrew their sesame allergies, but the data still helped to support the argument in favor of adding sesame seeds to the list of allergens that should be included on food labels.1,2,4
Sesame seeds are not the only seed that can produce an allergic reaction, but it is the one most parents and pediatricians will encounter, according to Wei An, MD, a board-certified allergist and immunologist at Connecticut Asthma and Allergy Center.
Clinicians are noticing a high risk of sesame and other seed allergies in people with known peanut and tree nut allergies, he said.
Although sesame seems to be the most common seed allergy, An noted that other common seed types can trigger reactions, including the following:
Children are not usually allergic to multiple types of seeds, An said, but the risk of a seed allergy is higher in those who are allergic to peanuts, tree nuts, and other types of foods overall. He said that as many as one-quarter of children with peanut allergies also have allergies to certain seeds and tree nuts.
Testing for seed allergies can be done in 2 ways—by testing blood samples or performing a skin test. Skin testing has been found to be most accurate for detecting a sensitivity to seeds in particular, An explained.
“Sesame proteins are a protein similar to tree pollens like birch, so you can get false-positives,” he said. “You can be fooled by blood work if it’s not a true allergy.”
A negative result on a skin test for sesame and other seed allergies is about 90% accurate, An noted. Skin testing is the preferred method of diagnosing seed allergies, but how many types of seeds an allergist tests for may depend on the familial risk and how concerning the allergy risk is for a particular individual.
“Levels of concern are different,” An said. “Some families are really worried if there is already a peanut allergy in the family.”
Seed allergies usually present with cutaneous reactions, such as facial or full body hives, An explained. However, vomiting and respiratory symptoms such as anaphylaxis can also happen. Anaphylaxis is not as common in seed allergies as it is in some other types of allergies, but severe reactions are possible and most likely to occur in people who have a strong personal or family history of other food allergies.
One of the biggest challenges in addressing seed allergies has been awareness, An noted. Seed allergies are not discussed as much as other types, and they were not required to be included on packaged food labels prior to 2023. Additionally, seeds can be in many unexpected foods, so there is also a risk with restaurant fare as well as homemade items. Hummus, tahini, and pesto are among the foods that contain sesame and other seeds that could trigger a reaction.
Sesame and other seed oils do not typically trigger the same reactions as the seeds themselves, An added. This is because cooking temperatures tend to change the chemistry of the proteins in these allergens.
There also seems to be a dose-response relationship to seed allergies, An said. Some children with sesame allergies can tolerate a seed or two on a bagel, or they may only have a mild allergic reaction. A high concentration of seeds, on the other hand, will likely trigger a much more severe reaction, An pointed out.
As with other types of food allergies, seed allergies can make life difficult. Children with seed allergies often have at least a few other food allergies, and according to An these can carry a negative stigma. About one-quarter of all children with food allergies end up developing food aversions or phobias, he added.
It is possible to outgrow seed allergies, but An noted that this is not as common as it is for cow’s milk, for example. The majority of people with seed allergies will have them for a long time or even permanently.
In addition, there does not appear to be any benefit to early introduction to seeds as a preventive strategy, Ann said, as the allergies appear to be linked more to genetics than to exposure.
Treatment recommendations for seed allergy reactions are in line with other types of food allergy treatments, according to An. Antihistamines can help control allergic reactions, and epinephrine injections should be used any time symptoms extend beyond hives or other skin reactions.
Oral immunotherapy (OIT)—a treatment that is increasingly being used to treat peanut allergies—has shown promise with seed allergies, An added. Sesame OIT has worked well among his patients, he said, and is usually carried out over a 5- to 6-month period. Some children who are treated with OIT for sesame allergies experience a complete reversal of their allergy, but others may require low to moderate daily doses to maintain their protection.
Although these allergies may be noticed in general pediatric practice first, a referral to an allergy or immunology specialist can help tailor testing and treatment strategies to help children who are allergic to seeds and other foods.
1. Allergic to sesame? Food labels now must list sesame as an allergen. FDA. Updated January 10, 2023. Accessed April 3, 2023.
2. Sokol K, Rasooly M, Dempsey C, et al. Prevalence and diagnosis of sesame allergy in children with IgE-mediated food allergy. Pediatr Allergy Immunol. 2020;31(2):214-218. doi:10.1111/pai.13143
3. Food allergies: what you need to know. FDA. 2022. Updated April 12, 2023. Accessed April 3, 2023.
4. Sesame allergy and food labels. Allergy & Asthma Network. Accessed April 5, 2023.