Chestnuts are in the Fagaceae family of plants which also includes beech and oak trees.

Chestnuts (not to be confused with horse chestnuts or water chestnuts, which are not related) have 4 allergenic proteins. Water chestnuts are in the Cyperaceae family of plants and are not closely related to other tree nuts, chestnuts or peanuts. Other plants in this family are usually grasses and rushes.

Cas s 1 is a Bet v 1 allergen, so is associated with Pollen Food Allergy Syndrome.

Cas s 5 is a chitinase, this is a plant derived enzyme made by the plant to act as a defence against fungal attacks. Chitinase is a protein which can cause allergic reactions to those who have a latex allergy.

Cas s 8 is a Lipid Transfer Protein. These are panallergens found in many plants.

Cas s 9 is a small heat shock protein, unique to chestnuts.

Note that chestnuts are not related to other tree nuts or peanuts, so are not technically classified as nuts at all. There are no seed storage proteins present in chestnuts (or none that have yet been identified), which is typical of tree nuts.

Chestnuts are a low FODMAP food. FODMAP stands for Fermentable oligosaccharides, disaccharides, monosaccharides and polyols. Foods high in FODMAPs can cause symptoms of food intolerance, affecting the gastro intestinal system and this can be mistaken for a true IgE food allergy.

Chestnuts are high in salicylates. Salicylates have the potential to cause worsening of asthma, swelling, itching and hives as well as food intolerance symptoms in people who are sensitive to salicylates.

You can read more about Food Intolerances on the dedicated Food Intolerance Page.

You may have Pollen Food Allergy Syndrome if you suffer from chestnut allergy with oral allergy symptoms to 3 or more of the foods mentioned in cross reactivity section.

Chestnut allergy is most commonly seen in conjunction with allergies to other foods presenting as Latex Food Syndrome. This is due to the high level of chitinase. Latex Food Syndrome is caused by the body confusing the proteins it encounters in food to that of latex proteins to which it is already sensitised.

LTP's are a group of proteins which can cause more serious allergic reactions in patients, you may suffer from LTP Syndrome if you suffer IgE type allergy symptoms to foods mentioned in the cross reactivity section below.

If sensitised to birch tree pollen you may have Pollen Food Allergy Syndrome and may also react to apple, pear, peach, plum, nectarine, apricots, cherries, chestnut, kiwi, tomato, celery, carrot, potato, parsnip, pepper, dill, cumin, peas, coriander, fennel, hazelnut, walnut, almonds, peanuts, lentils and beans.

Foods linked to Latex Food Syndrome may have linked allergies to foods which contain high levels of chitinase, like avocado, banana, corn (maize), kiwi, papaya, pomegranate and tomatoes.

Common foods involved in LTP allergy include kiwi, strawberries, sunflower seeds, walnut, apple, mulberry, banana, pea, apricot, cherry, plum, almond, peach pomegranate, raspberry, tomato, grape, celery, peanut, asparagus, cabbage, broccoli, chestnut, lemon, tangerine, orange, hazelnut, lettuce, lentils, lupin, green bean, pear, mustard, wheat and maize.

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