Sesame allergy is a growing concern, often leading to confusion due to its frequent association with nut allergies. Many people are unsure whether sesame falls into the category of nuts or seeds, leading to questions about its allergenic properties.
Sesame’s Botanical Identity
Botanically, sesame (Sesamum indicum) is classified as a seed, not a nut. It comes from a flowering plant and its edible seeds grow in pods. Despite being a seed, sesame is considered a major food allergen due to its potential for severe reactions.
It is recognized as the ninth major food allergen in the United States, requiring clear labeling on packaged foods since January 1, 2023. This makes it a distinct allergen, separate from tree nuts or peanuts, which are legumes. The high oil content and specific proteins in sesame seeds contribute to its allergenic potential.
Recognizing Sesame Allergy
Symptoms of a sesame allergy can range from mild to severe, typically appearing quickly, within minutes to an hour after exposure. Mild reactions may include hives, itching, or swelling, particularly around the face, as well as an itchy throat, vomiting, or diarrhea. These symptoms reflect the immune system’s response to sesame proteins.
More severe reactions, such as anaphylaxis, can be life-threatening and require immediate medical attention. Anaphylaxis symptoms can include difficulty breathing, wheezing, throat tightness, dizziness, a rapid or weak pulse, or a sudden drop in blood pressure. Approximately 0.23% of the U.S. population has a convincing sesame allergy, and about 15% of children with a sesame allergy may experience severe reactions.
Comparing Sesame and Tree Nut Allergies
Sesame allergies are distinct from tree nut allergies, as sesame is botanically a seed and tree nuts are true nuts. Despite this botanical difference, confusion often arises because both can cause serious allergic reactions and are sometimes found in similar food products. The proteins in sesame seeds can share some structural similarities with proteins found in certain nuts, which might lead to cross-reactivity in some individuals.
While direct botanical cross-reactivity is not always the primary factor, individuals with peanut and tree nut allergies may have a higher likelihood of also being allergic to sesame. For instance, some studies indicate that a significant percentage of people with convincing IgE-mediated sesame allergy also have other food allergies, with peanut allergy being common among them. This co-occurrence of allergies rather than direct cross-reactivity is an important consideration for diagnosis and management.
Managing a Sesame Allergy
Diagnosing a sesame allergy typically involves a medical evaluation, including a review of symptoms and dietary history. Allergists may use skin prick tests, where a small amount of sesame protein is applied to the skin to observe a reaction. Blood tests that measure IgE antibodies specific to sesame can also support a diagnosis. In some cases, an oral food challenge, conducted under medical supervision, may be necessary to confirm the allergy.
Managing a sesame allergy primarily involves strict avoidance of sesame and products containing it. Carefully reading food labels is important, as sesame can be listed under various names like tahini, benne, gingelly, or sesamol. Hidden sources can include baked goods, hummus, certain Asian and Middle Eastern cuisines, salad dressings, and even some natural flavorings or spices. Cross-contamination in food preparation is also a risk. Individuals with a sesame allergy should always carry an emergency action plan and prescribed epinephrine auto-injectors for severe reactions.