Sesame Allergy & Natasha’s Law: Navigating Hidden Seeds in UK Food

Published: 28 February 2026

Sesame allergy is one of the most common and potentially serious food allergies in the UK, yet it remains one of the hardest to manage in daily life. Sesame seeds are small, often baked into bread and rolls where they can be nearly invisible, and sesame paste (tahini) is a staple ingredient in hummus, sauces, and dressings that may not immediately signal a risk. The tragic death of Natasha Ednan-Laperouse in 2016 — who suffered a fatal anaphylactic reaction to a baguette containing sesame that was not labelled — led directly to a landmark change in UK food law known as Natasha’s Law.

This guide explains what sesame allergy involves, how Natasha’s Law has changed food labelling in the UK, where sesame hides in everyday foods, how to recognise the symptoms of a reaction, and when IgE blood testing can help clarify your sensitisation pattern. If you or someone in your family has a confirmed or suspected food allergy, understanding the practical landscape of sesame is essential.

Why Sesame Is a High-Risk Allergen

Sesame (Sesamum indicum) is one of the 14 major allergens recognised under UK food law. It is estimated to affect approximately 0.1–0.2 per cent of the UK population, though the true figure may be higher as awareness increases (Allergy UK, 2025). While this makes it less prevalent than peanut or cow’s milk allergy, sesame is significant because:

• Anaphylaxis risk is well documented. Sesame is among the foods most commonly associated with severe allergic reactions, including anaphylaxis, in the UK (Anaphylaxis UK, 2025).
• It is difficult to detect in food. Sesame seeds can be very small and are frequently baked into bread products. Sesame paste and oil are widely used in cooking but may not be immediately recognisable as allergen-containing ingredients.
• Cross-contact is common. Bakeries, delis, and food production lines often handle sesame alongside other products, creating a risk of unintentional contamination.
• It is less likely to be outgrown. Unlike some childhood food allergies (such as milk and egg), sesame allergy appears to persist into adulthood in a significant majority of cases (BSACI, 2023).

Seed allergy can also extend beyond sesame. Some people with sesame allergy report reactions to other seeds such as poppy, sunflower, or flaxseed — though these are typically separate allergies rather than true cross-reactivity. Specific IgE testing for individual allergens can help clarify which seeds are relevant to you.

Natasha’s Law in the UK: What Changed for Prepacked for Direct Sale Foods

Natasha’s Law UK (formally the UK Food Information Amendment) came into force on 1 October 2021. It was introduced following the death of 15-year-old Natasha Ednan-Laperouse, who suffered a fatal anaphylactic reaction after eating a Pret A Manger baguette containing sesame seeds that was not labelled with its ingredients (Food Standards Agency, 2025).

What the Law Requires

Before Natasha’s Law, food that was prepacked for direct sale (PPDS) — such as sandwiches, wraps, and salads made on the premises and then wrapped or packaged before a customer selects them — was not required to carry a full ingredients list. Allergen information could be provided verbally or via a sign.

Under the new law, all PPDS food must now carry:

• A full ingredients list on the packaging
• All 14 major allergens (including sesame) emphasised within that list — typically in bold

This means that a sandwich containing sesame seeds or tahini made and packaged in a café, bakery, or deli must now have a visible label clearly listing sesame as an ingredient.

What the Law Does Not Cover

• Non-prepacked food — meals served in restaurants, food made to order, and loose items (such as a bread roll selected from a bakery display) are not required to have a written ingredients label. Allergen information must still be available on request, but this relies on staff knowledge and communication.
• Cross-contamination warnings — “may contain sesame” or “made in a factory handling sesame” are precautionary statements. These are voluntary under UK law and are not standardised, meaning their presence (or absence) does not guarantee safety (Food Standards Agency, 2025).
• Imported products — foods imported from outside the UK may follow different labelling standards. Always check the label carefully.

Where Sesame Hides: Everyday UK Foods and Cuisines

One of the biggest challenges with sesame allergy is the sheer range of products that contain sesame — and how easy it is to miss. The term “hidden allergens in bread” is particularly relevant to sesame, because seeds baked into or onto bread rolls, buns, and baguettes can be extremely small and visually indistinguishable from the crust.

Common Sources of Sesame in UK Food

• Bread and bakery products — burger buns, bagels, breadsticks, seeded loaves, brioche, and flatbreads. Even “plain” bread may be contaminated if produced alongside seeded varieties.
• Hummus and tahini — tahini (ground sesame paste) is the primary ingredient in traditional hummus. If you have a sesame allergy, standard hummus is not safe. This is sometimes described as a “hummus allergy” — though the allergy is to the sesame in the tahini rather than to chickpeas.
• Asian cuisines — sesame oil is widely used in Chinese, Japanese, Korean, and Thai cooking. Sesame seeds are used as garnishes in sushi, stir-fries, and noodle dishes.
• Middle Eastern and Mediterranean foods — falafel, halva (a confection made from tahini), baba ghanoush, dukkah, and many dressings and sauces.
• Crackers, cereal bars, and snacks — sesame is a common ingredient in savoury biscuits, rice cakes, and seed-based snack bars.
• Processed foods — sesame flour, sesame protein, and sesame oil can appear in processed sauces, marinades, dressings, and ready meals. Always check the label.
• Cosmetics and toiletries — some skin care products, lip balms, and hair products contain sesame oil. While reactions from skin contact are uncommon, they have been reported.

Symptoms: Mild vs Severe and When It’s an Emergency

Sesame allergy can produce a range of symptoms, from mild oral discomfort to life-threatening anaphylaxis. The severity can vary between individuals and between episodes in the same person (NHS, 2025).

Mild to Moderate Symptoms

• Itching or tingling in the mouth, lips, or throat
• Hives (urticaria) — raised, itchy welts on the skin
• Skin flushing or redness
• Swelling of the lips, face, or eyes (angioedema)
• Abdominal pain, nausea, or vomiting
• Nasal congestion or sneezing

Severe Symptoms (Anaphylaxis)

Anaphylaxis risk with sesame is well established. Severe reactions can develop rapidly and may include:

• Difficulty breathing or wheezing
• Swelling of the tongue or throat that affects swallowing or breathing
• A sudden drop in blood pressure
• Feeling faint, dizzy, or losing consciousness
• Widespread hives combined with any of the above

Testing: Specific IgE and Sesame Components

If you suspect a sesame allergy, an IgE blood test can provide objective information about your immune system’s response to sesame proteins. Here is what is available:

Standard Specific IgE Testing

A specific IgE blood test measures your IgE antibody response to a whole sesame extract. A positive result indicates sensitisation — your immune system has produced IgE antibodies against sesame. However, sensitisation does not automatically confirm clinical allergy. Some people with detectable sesame IgE tolerate sesame without any symptoms (BSACI, 2023).

Component-Resolved Diagnostics (CRD)

Component testing measures IgE against individual allergenic proteins within sesame. The most clinically relevant sesame component currently available is:

• Ses i 1 — a 2S albumin storage protein. IgE to Ses i 1 is associated with a higher likelihood of clinical allergy and a potentially higher anaphylaxis risk, because 2S albumins are heat-stable and digestion-resistant (BSACI, 2023).

A positive result to Ses i 1 can help a clinician assess the likelihood that your sensitisation is clinically significant, while a positive whole-sesame IgE without component positivity may sometimes reflect cross-reactivity with other seeds or pollens rather than a primary sesame allergy.

What Testing Cannot Do

• A blood test result cannot diagnose sesame allergy on its own. Diagnosis requires a clinician to interpret your IgE results alongside your symptom history, timing, and reaction pattern.
• IgE levels do not reliably predict the severity of future reactions (NICE, 2025).
• A negative result does not always rule out allergy — some people have clinically relevant allergies not fully captured by available IgE panels.

For a detailed guide on reading your results, including kU/L values, reference ranges, and cross-reactivity patterns, see our guide to understanding your allergy lab report.

Eating Out and Shopping: A Practical Checklist

Living with sesame allergy in the UK requires consistent vigilance, but practical habits can significantly reduce risk:

Shopping

• Read every label, every time. Even products you have bought before can change their ingredients or manufacturing processes. Under UK law, sesame must be emphasised (usually in bold) in the ingredients list.
• Understand “may contain” statements. These are voluntary and not standardised. A product without a “may contain sesame” warning is not necessarily free from cross-contamination. If in doubt, contact the manufacturer directly.
• Be cautious with bakery products. Bread, rolls, and pastries from in-store bakeries may be produced alongside sesame-topped items. Ask about cross-contact procedures.
• Check non-food products. Some cosmetics, lip balms, and skin care products contain sesame oil (Sesamum indicum oil on the label).

Eating Out

• Inform the restaurant clearly. UK food businesses must provide allergen information for the 14 major allergens, including sesame, on request. Ask to speak to the chef or manager.
• Ask specifically about sesame oil. In Asian restaurants, sesame oil is commonly used in cooking. It may not be mentioned on the menu unless you ask.
• Beware of cross-contact. In busy kitchens, sesame seeds from one dish can contaminate another. Ask about preparation areas and shared cooking surfaces.
• Carry your adrenaline auto-injector. If you have been prescribed one, ensure it is within date and accessible at all times when eating out.
• Consider an allergy card. A printed card in English (and, if relevant, other languages) listing your allergy can help communicate clearly with kitchen staff.

School, Childcare, and Workplace: Risk Reduction Essentials

Managing sesame allergy in settings where you are not in direct control of food preparation requires clear communication and planning:

For Children

• Individual healthcare plan (IHP). Work with your child’s school to create a documented plan that includes the allergy, symptoms to watch for, emergency treatment steps, and where the adrenaline auto-injector is stored.
• Staff training. Ensure relevant staff know how to recognise an allergic reaction and how to administer an adrenaline auto-injector. Anaphylaxis UK provides free training resources for schools.
• Lunch and snack management. If your child takes a packed lunch, this gives you full control over ingredients. If they eat school meals, confirm with the catering provider that sesame is flagged and managed.
• Class activities. Cooking, art, and science activities may involve seeds or food products. Ensure teachers are aware and can substitute where needed.

For the Workplace

• Inform colleagues and managers if you have a severe seed allergy — particularly if there is a shared kitchen or communal food.
• Keep your adrenaline auto-injector at your desk or in an accessible location, and ensure at least one colleague knows where it is and how to use it.
• Label your own food clearly and avoid shared utensils that may have been used with sesame-containing products.

How Diagnostic-Only Testing Helps

If you suspect a sesame allergy, obtaining objective IgE data can be a valuable step — whether you are awaiting an NHS specialist appointment or want to bring evidence-based results to your GP. At AllergyClinic.co.uk, we offer private allergy testing in London through nurse-led venepuncture and accredited laboratory analysis. Here is how the process works:

1. Appointment. A qualified nurse takes a blood sample at one of our clinic locations. The process is straightforward and typically takes a few minutes.
2. Laboratory analysis. Your blood sample is sent to an accredited laboratory for specific IgE testing. This can include whole sesame extract and, where appropriate, the sesame component Ses i 1.
3. Report delivery. You receive a detailed laboratory report showing your specific IgE levels for each allergen tested, measured in kU/L.
4. Next steps. You take your report to your GP, allergist, or chosen clinician for interpretation. They will assess your results alongside your clinical history and advise on management — including whether further investigation (such as supervised oral challenge) is appropriate.

Please note: Our service is diagnostic sampling only. We do not provide clinical consultations, diagnosis, prescribing, or treatment plans. Your laboratory report should always be interpreted by a qualified healthcare professional who can consider your full medical history.

Questions to Ask After You Receive Your Report

When you take your allergy test report to your GP or specialist, these questions may help guide a productive discussion:

• Does my IgE result suggest genuine sesame sensitisation, or could it reflect cross-reactivity with other seeds or pollens?
• Is component testing (Ses i 1) available and would it add useful information in my case?
• Based on my history and test results, do I need to strictly avoid all forms of sesame — including refined sesame oil?
• Should I be prescribed an adrenaline auto-injector?
• Do I need a referral to an NHS or private allergy specialist?
• Is my child likely to outgrow this allergy, and how should we monitor over time?

Frequently Asked Questions

Is sesame one of the 14 allergens in UK law?

Yes. Sesame is one of the 14 major allergens that must be declared on pre-packed food labels in the UK under retained EU Regulation 1169/2011. It must also be declared on PPDS food under Natasha’s Law UK, which came into force in October 2021. Restaurants and food businesses must provide allergen information on request (Food Standards Agency, 2025).

Can you be allergic to hummus?

Hummus is made primarily from chickpeas and tahini (ground sesame seeds). If you have a sesame allergy, the tahini in hummus can trigger an allergic reaction — this is sometimes referred to as “hummus allergy”, though the allergy is to the sesame rather than the chickpeas. Some people also have a separate chickpea allergy. Specific IgE testing can help determine which component is relevant.

Why is sesame so hard to avoid?

Sesame appears in a wide range of products — as visible seeds on bread, as tahini paste in sauces and dips, and as sesame oil in cooking. Hidden allergens in bread are a particular concern because small seeds baked into the crust can be nearly invisible. Sesame flour and protein can also appear in processed foods without being immediately obvious. While UK law requires declaration, precautionary “may contain” warnings are voluntary (Food Standards Agency, 2025).

What does Natasha’s Law mean for sesame allergy?

Natasha’s Law requires all PPDS food to carry a full ingredients list with allergens emphasised. This closed a gap where items like sandwiches and wraps made on premises could be sold without listing their ingredients. For people with sesame allergy, this means you can now check the label on a wrapped sandwich in a café and see whether it contains sesame (Food Standards Agency, 2025).

Can sesame allergy cause anaphylaxis?

Yes. Sesame is recognised as a food allergen that can cause anaphylaxis. Anaphylaxis UK reports that sesame is among the allergens most commonly associated with severe reactions in the UK. If you experience difficulty breathing, throat swelling, dizziness, or collapse after eating sesame, use your adrenaline auto-injector if prescribed and call 999 immediately (Anaphylaxis UK, 2025).

Can a blood test tell me if I am allergic to sesame?

A specific IgE blood test can determine whether your immune system has produced IgE antibodies against sesame proteins — this is called sensitisation. A positive result supports the possibility of sesame allergy but does not confirm it alone. Component testing (Ses i 1) can provide further detail. All results should be interpreted by a qualified clinician alongside your symptom history (BSACI, 2023).

Is sesame oil safe if you have a sesame allergy?

It depends. Highly refined sesame oil has most of the allergenic protein removed and may be tolerated by some people with mild sensitisation. However, cold-pressed or unrefined sesame oil retains more protein and is more likely to trigger a reaction. Most guidelines recommend avoiding all sesame oil unless your clinician has specifically advised otherwise (Allergy UK, 2025).

Can you develop sesame allergy later in life?

Yes. While sesame allergy often begins in childhood, adult-onset sesame allergy has been reported. If you develop new symptoms after eating sesame-containing foods, it is worth discussing with your GP and considering specific IgE testing (NHS, 2025).

Do children outgrow sesame allergy?

Sesame allergy is generally considered less likely to be outgrown than milk or egg allergy. Studies suggest approximately 20–30 per cent of children may outgrow it. Periodic reassessment by a specialist can help determine whether sensitisation levels have changed. Any reintroduction should be guided by a qualified clinician (BSACI, 2023).

Is sesame allergy related to other seed or nut allergies?

Sesame is a seed, not a tree nut or peanut, but some people with sesame allergy also have allergies to other seeds or nuts. This can occur because of separate primary allergies or occasionally because of cross-reactivity between similar storage proteins. Specific IgE testing for individual allergens can help clarify which foods are relevant to you (Allergy UK, 2025).

Glossary

• IgE (Immunoglobulin E) — a type of antibody produced by the immune system. In allergic individuals, IgE antibodies bind to specific allergen proteins and trigger allergic symptoms upon re-exposure.
• kU/L (kilo units per litre) — the standard unit used to measure specific IgE levels in blood test results. Higher values indicate greater sensitisation, but do not reliably predict symptom severity.
• Sensitisation — the presence of specific IgE antibodies against an allergen. Sensitisation indicates immune recognition but does not automatically mean you will experience symptoms on exposure.
• Component-resolved diagnostics (CRD) — an advanced form of IgE testing that measures antibodies against individual allergenic proteins within an allergen source, rather than the whole extract.
• 2S albumin — a family of storage proteins found in seeds and nuts. They are heat-stable and digestion-resistant, and sensitisation to 2S albumins (such as Ses i 1 in sesame) is often associated with a higher risk of clinical reactions.
• Cross-reactivity — when IgE antibodies directed against one allergen also recognise structurally similar proteins from a different source.
• PPDS (Prepacked for Direct Sale) — food that is prepared and packaged at the same location from which it is sold, before a customer selects it. Under Natasha’s Law, PPDS food must carry a full ingredients list with allergens emphasised.

Sources

• Allergy UK (2025). Sesame Allergy Factsheet. Available at: www.allergyuk.org [Accessed 28 February 2026].
• Anaphylaxis UK (2025). Anaphylaxis: Recognition and Emergency Treatment. Available at: www.anaphylaxis.org.uk [Accessed 28 February 2026].
• BSACI (2023). Guidelines for the Diagnosis and Management of Food Allergy. British Society for Allergy and Clinical Immunology. Available at: www.bsaci.org [Accessed 28 February 2026].
• Food Standards Agency (2025). Allergen Labelling, Natasha’s Law and PPDS Guidance. Available at: www.food.gov.uk [Accessed 28 February 2026].
• NHS (2025). Food Allergy — Overview. Available at: www.nhs.uk [Accessed 28 February 2026].
• NICE (2025). Food Allergy in Under 19s: Assessment and Diagnosis. Available at: www.nice.org.uk [Accessed 28 February 2026].