Pistachio nuts are in the Anacardiaceae family of plants. Other plants in this family include cashew nuts, mango and sumac.

There are 5 allergens in pistachio nuts. Pis v 1, 2, 3, 4 and 5.

Most tree nut allergies are caused by seed storage proteins, pistachios have all 3 types of seed storage protein. Pis v 1 is a 2S seed storage albumin protein.

Pis v 2 and 5 are 11S seed storage globulin proteins, also known as legumin proteins.

Pis v 3 is a vicilin protein, also called a 7S seed storage globulin protein. These seed storage proteins can cause people to be allergic to whole groups of tree nuts, seeds and legumes.

Pis v 4 is a manganese superoxide dismutase which is a plant enzyme.

Pistachios are high 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.

Pistachio nuts are a food high in salicylates. Salicylates have the potential to cause gastrointestinal food intolerance symptoms in people who are sensitive to salicylates.

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

Pistachio allergy is not currently associated with any allergic syndromes.

The most studied cross reactivity is between pistachio and cashew nuts.

Other food containing 2S albumin seed storage proteins are cashews, peanuts, brazil nuts, mustard seed, rapeseed, turnip, chickpeas, hazelnuts, pecan nuts, buckwheat, soya, sunflower seeds, walnuts, kiwi, castor beans and sesame seeds.

Other foods containing 7S seed storage proteins are peanuts, cashews, pecan, hazelnut, soya beans, walnut, macadamia nuts, sesame and lupin all contain 2S seed storage proteins. Fruits and vegetables containing these proteins are coconut, mung beans and peas. 7S seed storage proteins are also found in buckwheat and lentils.

11S seed storage proteins are also found in kiwi, cashew, pecan, macadamia, peanut, brazil nut, pumpkin, soya beans, walnut, pistachio, sesame and mustard.

You can download a Tree Nut Allergy Factsheet from the Allergy Resources Ko-fi Shop for just $0.50 (£0.40 or €0.45). This has up to date information on which foods contain linked allergens and what foods to avoid if you think you have an allergy to tree nuts.

Note that these food lists are not exhaustive, the most up to date information is on the Cross Reactivity Tool.

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