Can you be allergic to maple syrup?

Quick answer

Yes, it is possible to be allergic to maple syrup. Maple syrup allergy is rare but can cause symptoms like hives, swelling, abdominal pain, vomiting, and anaphylaxis in sensitive individuals. The main allergenic proteins are thought to be invertases and other enzymes naturally present in maple syrup. Allergy testing can help diagnose maple syrup allergy. Strict avoidance is the main treatment, along with carrying epinephrine for anaphylaxis.

What is maple syrup?

Maple syrup is a sweet, thick syrup made by boiling down the sap of maple trees, primarily the sugar maple tree. It takes about 40 gallons of maple sap to make 1 gallon of maple syrup. Pure maple syrup contains over 20 different compounds that provide its unique flavor, including sugars like sucrose, glucose, and fructose; amino acids; vitamins; and minerals like manganese, riboflavin, and zinc. It has a high sugar content but a low glycemic index, meaning the sugars are released more slowly into the bloodstream.

Maple syrup is commonly used as a pancake topping and sweetener for baking. It can range in color from golden to dark brown with a darker color and more robust flavor as more caramelization occurs. Maple syrup is often graded by color with designations like “Grade A Light Amber” or “Grade A Dark Color, Robust Taste.”

Maple syrup production

Maple syrup production begins in late winter or early spring when temperatures fall below freezing at night and rise above freezing during the day. This fluctuating temperature creates pressure differences within the tree that causes the sap to flow. Holes are drilled into maple trees and taps inserted to direct the sap into buckets or tubing systems.

The harvested sap looks like water with a slightly sweet taste. It contains only about 2-3% sugar. The sap is boiled down to evaporate the water, concentrating the sugars and flavor compounds. It takes roughly 40:1ratio of sap to syrup. As it boils, water evaporates off and the sugars caramelize, creating the characteristic maple flavor and color. It is filtered while hot before bottling.

Is maple syrup allergy possible?

Yes, it is possible for some people to be allergic to maple syrup, although it is considered rare. Like other food allergies, maple syrup allergy is caused by the immune system inappropriately reacting to specific proteins in the syrup as if they were harmful. This triggers the release of chemicals like histamine that cause the symptoms of an allergic reaction.

Several case reports have documented allergic reactions to maple syrup, ranging from mild symptoms like hives and itchy skin to severe life-threatening anaphylaxis. The prevalence is unknown but likely very low. One study found 2 positive skin tests for maple syrup allergy out of 546 children tested.

Maple syrup allergy symptoms

Allergic reactions to maple syrup can cause diverse symptoms:

– Hives, itchy rash, or swelling around the lips, face, tongue, and throat
– Stomach pain, nausea, vomiting, diarrhea
– Runny nose, coughing, wheezing
– Dizziness, fainting due to low blood pressure
– Anaphylaxis – a severe reaction involving multiple symptoms that can be fatal if untreated

Symptoms typically start within minutes to two hours after consuming maple syrup. Even a small amount may provoke a reaction in very sensitive individuals. Mild symptoms may resolve on their own, but severe reactions require immediate medical care.

Oral allergy syndrome

Some people may experience an oral allergy syndrome reaction to maple syrup. This is a localized allergic reaction in the mouth when certain fresh fruits, vegetables, or nuts are eaten. It happens because the proteins in the food are similar to pollen proteins which the person is allergic to. The proteins can cross-react with allergy antibodies for pollen, triggering mild symptoms like itching or tingling of the lips, mouth, and throat. Cooked or processed versions of the food may not cause a reaction.

Oral allergy syndrome to maple syrup could occur in those with allergies to certain tree pollens that are botanically related to maple trees, like oak, birch, or poplar. Heating the maple syrup may break down the labile proteins involved and prevent the reaction.

What causes maple syrup allergy?

Researchers have identified at least two proteins in maple syrup that may be responsible for maple syrup allergy:

– Invertase – This enzyme naturally occurs in maple sap/syrup and helps break down sucrose into glucose and fructose. Similar invertase enzymes are also found in yeast, pollens, and bee venom, which are common allergens.

– Homologous protein – There is a protein in maple syrup that is structurally similar to a major allergen found birch tree pollen. This homologous protein could explain oral allergy syndrome reactions to maple syrup in people with birch pollen allergy.

Other enzymes like amylase or unknown proteins could also be potential allergens. More research is needed on the specific allergenic maple syrup proteins and cross-reactivities with other common environmental allergens.

Why do some people develop maple syrup allergy?

The reasons why only some people develop allergies to particular foods like maple syrup are not totally understood but likely involve a combination of genetic and environmental factors. Possible reasons include:

– Genetic predisposition – Having other allergic conditions or a family history increases the risk. Certain genes control immune system responses.

– Exposure – Repeated or early-life exposure to maple products like syrup or wood may sensitize someone to maple allergens.

– Cross-reactivity – Exposure to a closely related allergen like birch pollen can prime the immune system.

– Timing – The hygiene hypothesis suggests that reduced microbial exposure in childhood fails to train the immune system properly, increasing the risk of allergies.

– Damage to gut barrier – Disruption in intestinal permeability may allow allergens to enter the bloodstream and trigger immune reactions.

Diagnosing maple syrup allergy

Maple syrup allergy can be challenging to diagnose since reactions and allergy testing are not always consistent. The main methods include:

Allergy testing

– Skin prick test – Drops containing maple syrup extract are placed on the skin and pricked with a small needle. A positive result is a raised bump or hive at the site signaling an IgE mediated reaction.

– Blood tests – High levels of anti-maple syrup IgE antibodies in the blood indicate sensitization. This predicts but does not guarantee clinical reactivity.

– Oral food challenge – Starting with a small amount of maple syrup and incrementally increasing the dose can help confirm an allergy when testing is ambiguous. Should only be done under medical supervision due to the risk of a severe reaction.

Review of health history

An allergist will review the person’s detailed medical history, looking for evidence of symptoms occurring in relation to maple syrup exposure. This can help determine if maple syrup is the likely cause of the reaction.

Keeping a food and symptom diary can help identify triggering products and establish a timeline of when reactions occur. Saving product labels and taking photos of skin reactions may also assist with diagnosis.

Elimination diet

Avoiding maple syrup completely for a period of time and monitoring symptoms can sometimes reveal a maple allergy, especially when testing is inconclusive. Reintroduction in a clinical setting may be used to confirm.

Treating maple syrup allergy

There is currently no cure for maple syrup allergy. The primary treatment is strict avoidance of all maple containing foods and products:


– Read all product labels carefully, watching for words like “maple”, “maple syrup”, “maple flavoring”, etc.

– Avoid maple syrup, maple candy, maple fudge, maple taffy, maple cream, and maple sugar.

– Be aware of hidden sources like maple flavoring in baked goods, candy, cereal, ice cream, granola bars, coffee syrups, etc.

– Check with manufacturers about shared equipment and cross-contact risks.

– Carefully read restaurant menus and inform staff about the allergy when dining out. Request allergen-free preparation.

– Look out for coconut syrup or other substitutions incorrectly labeled as maple syrup.

Epinephrine auto-injectors

Those with a known maple syrup allergy should have epinephrine like EpiPens available at all times to stop anaphylaxis. Epinephrine should be injected immediately at the first signs of a serious reaction. Prompt injection is critical for survival in anaphylaxis.


Oral antihistamines like diphenhydramine (Benadryl) can help relieve mild allergy symptoms like hives, runny nose, or nausea but do not treat anaphylaxis. They are often used in combination with epinephrine for anaphylaxis reactions.


Allergy shots or sublingual immunotherapy that can increase tolerance to some environmental allergens have not been studied specifically for maple syrup allergy. There may be some benefit if cross-reactive tree pollen allergies are also treated. Additional research is needed.

Living with maple syrup allergy

Having a quality of life with maple syrup allergy involves vigilance in avoiding exposure and excellent communication with those around you. Some tips include:

Be prepared

– Wear a medical alert bracelet or necklace stating the allergy.

– Make sure caregivers, family, and friends know how to use epinephrine in an emergency. Have them help check labels.

– Call ahead when traveling or eating out to explain allergy needs.

– Bring safe snacks/food as a backup.

Reduce risk

– Wash hands after touching products containing maple. Sanitize surfaces, utensils, and dishes.

– Get ingredients lists from manufacturers whenever there is uncertainty about cross-contamination.

– Politely decline food offerings from others unless ingredients are known. Avoid potlucks.

– If reacting, immediately remove the food, wash out mouth, and take medication as directed.

Enjoy alternatives

– Maple flavoring without actual maple may be tolerated. Always check labels first.

– Try trehalose, sorghum, date, or other syrups as maple substitutes.

– For baking, sugar, honey, agave nectar, or molasses can provide sweetness in place of maple syrup.

– Explore maple-free recipes for pancakes, granola, candy, and other typical maple foods.

Prognosis of maple syrup allergy

The long-term outlook for maple syrup allergy depends on the individual. Avoidance helps prevent reactions, but accidental exposures may still occur and reactions can be unpredictable.

Potential outcomes include:

– Persistent allergy – Maple syrup allergy often persists for years if not lifelong in affected individuals.

– Reduction in symptoms – Some children may outgrow or develop lesser reactions to maple over time.

– Development of tolerance – In rare cases, regular ingestion under medical supervision may increase tolerance. This is not routinely recommended due to risks.

– Loss of sensitivity – After prolonged complete avoidance, sensitivity could potentially decrease but may return with re-exposure.

– Severe anaphylaxis – Those with maple syrup allergy remain at risk for potentially fatal anaphylaxis without strict avoidance. Epinephrine is critical.

More research is needed to better understand the natural course of maple syrup allergy across different ages and populations. Working closely with an allergist can help develop an appropriate long term management plan.

Preventing maple syrup allergy

There are no sure ways to prevent the initial development of maple syrup allergy, but certain strategies may help reduce risk:


Exclusive breastfeeding for at least 4-6 months provides immunological benefits that may reduce allergic conditions. However, maple proteins can pass into breast milk and potentially sensitize infants. Strict maternal avoidance of maple while breastfeeding may help prevent reactions in high-risk infants.

Delay introducing maple

Current guidelines recommend introducing highly allergenic foods like tree nuts, eggs, fish, and shellfish early in complementary feeding between 4-6 months. Evidence is lacking on optimal timing for uncommon allergens like maple. Delaying introduction until 12 months or older may be beneficial.

Avoid skin exposure

Limiting early and frequent use of maple-based skin products like soaps or lotions might reduce the risk of sensitization in young children with known allergies. More research is needed on this preventative strategy.

Oral immunotherapy

Carefully controlled oral immunotherapy involves giving increasing doses of an allergen under close medical supervision to increase tolerance over time. This approach remains experimental and carries risks of serious reactions. It should only be attempted in clinical studies under an allergist’s guidance.


Maple syrup allergy is rare but can cause potentially serious reactions in sensitive individuals. The main allergens appear to be invertase enzymes and cross-reactive proteins also found in birch pollen. Diagnosis using skin or blood testing along with oral food challenges may be necessary to identify maple allergy, especially when reactions are mild or inconsistent. Strict avoidance is the cornerstone of management, along with carrying epinephrine auto-injectors in case of anaphylaxis. Additional studies are needed to better understand this unique food allergy and possible prevention strategies. While maple syrup itself must be avoided, individuals allergic to maple can still lead full, active lives by being vigilant label readers and preparing safe alternatives at home. With proper precautions, maple syrup allergy does not have to prevent enjoying family meals and social activities.

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