Peanuts (also known as groundnuts and monkey nuts) are legumes rather than tree nuts and grow underground. They are in the Fabaceae
family of plants which also includes peas, lentils, lupin, soya and other beans, pulses and legumes.
There are 18 allergens recognised by the World Health Organisation (WHO) associated with peanut allergy.
These allergens include 2S seed storage proteins
, commonly found in other nuts, seeds and legumes. Peanuts also contain 7S seed stoage proteins
, also known as vicilin and 11S seed storage proteins
, also known as legumin, which are also found in many seeds and legumes.
Peanuts also contain plant profilin proteins
, Lipid Transfer Proteins
(LTP) and Bet v 1 proteins
which are associated with Pollen Food Syndrome. These proteins are all considered to be panallergens - having the potential to cause allergic reactions across multiple groups of foods.
More recently there is interest in oleosin proteins
, which are found in the oils of certain nuts and seeds and are not denatured by heating. There are 4 oleosin proteins in peanuts which have been shown to cause allergic reactions.
Peanuts are a low FODMAP food. FODMAP stands for F
olyols. 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.
Peanuts are high in salicylates, so have the potential to cause gastrointestinal food intolerance symptoms in people who are sensitive to salicylates. Peanut butter, however, is very processed and is thought to be much lower in salicylates.
Peanuts contain high amounts of lectin. Lectins are another possible cause of food intolerance. Usually cooking foods with lectins makes them more digestible and can reduce the symptoms of food intolerance, peanut lectins however are heat stable, so their effect is not reduced by cooking.
Peanut allergy is often linked to LTP Syndrome
, where similarly shaped proteins in other plants resemble those in almonds and elicit an allergic reaction.
You may have Pollen-Food Allergy Syndrome
if you suffer from peanut allergy with oral allergy symptoms to 3 or more of the foods mentioned in the cross reactivity section.
Allergy to peanut is sometimes linked to Celery-Mugwort-Spice Syndrome
as the sensitising allergen is a profilin protein called Art v 4, these proteins are also sometimes also called Bet v 2 proteins.
There is a link between peanuts and Latex Food Syndrome
. The plant involved in latex allergy Hevea brasiliensis
, the rubber tree plant, has an allergen called Hev b 8 which is a profilin protein. Those very sensitised to latex may have a contact allergic reaction from other foods or plants containing profilin proteins, there is less evidence of this than sensitisation to other latex linked proteins like hevein and chitinases
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.
Other fruits containing profilins include celery, lychee, soyabeans, walnut, lupin, almonds, mustard, hazelnut, kiwi, pineapple, chilli, melon, orange, strawberry, apple, banana, aubergine (eggplant), peach, pear, tomato, dates, cherry, carrot, barley and wheat. Allergic reactions to some of these foods may be considered a marker of profilin hypersensitivity.
Other food containing 2S albumin seed storage proteins are cashews, peanuts, almonds, mustard seed, rapeseed, turnip, chickpeas, hazelnuts, pistachio, buckwheat, soya beans, sunflower seeds, walnuts, kiwi, castor beans and sesame seeds.
Other foods containing 7S seed storage proteins not mentioned in the list above are coconut, lupin, lentils, macadamia nuts and peas.
Almonds are the only other tree nut which contain 11S seed storage proteins, but not 7S or 2S proteins.
Other oleosin proteins are found in hazelnuts, buckwheat, palm oil and sesame seeds.
Allergen Encyclopedia - Peanuts
Science Direct - Peanut Allergy
DermNet NZ - Peanut
Allergy UK - Peanut Allergy
FARE - Peanut Allergy
ACAAI - Peanut Allergies
Anaphylaxis Campaign - Peanut Allergy
Allergy information for: Peanut; ground nuts; monkey nuts (Arachis hypogea)
Healthline - FODMAP Foods
ATP Science - Salicylate Food List
Articles and Journals
a href="https://www.sciencedirect.com/science/article/pii/S2772829322000492">Peanut, soy and emerging legume allergy in Canada, 2022
Association Between Earlier Introduction of Peanut and Prevalence of Peanut Allergy in Infants in Australia, 2022
Organ-specific symptom patterns during oral food challenge in children with peanut and tree nut allergy, 2022
Multi-scale study of the oral and gut environments in children with high and low threshold peanut allergy, 2022
Evaluating Knowledge and Implementation of Early Peanut Introduction Guidelines: A Cross-sectional Survey, 2022
Oral desensitization therapy for peanut allergy induces dynamic changes in peanut-specific immune responses, 2022
Life-threatening anaphylaxis to peanut — impossible to predict? 2022
Effect of Processing on the Structure and Allergenicity of Peanut Allergen Ara h 2 Roasted in a Matrix, 2022
Fatal anaphylaxis due to peanut exposure from oral intercourse, 2021
High-resolution epitope mapping by AllerScan reveals relationships between IgE and IgG repertoires during peanut oral immunotherapy, 2021
Current developments in the treatment of peanut allergy, 2021
Dietary Lectins: Gastrointestinal and Immune Effects, 2020
Peanut oleosins associated with severe peanut allergy-importance of lipophilic allergens for comprehensive allergy diagnostics, 2017
Development of a novel strategy to isolate lipophilic allergens (oleosins) from peanuts, 2015
Peanut defensins: Novel allergens isolated from lipophilic peanut extract, 2015
Detection and structural characterization of natural Ara h 7, the third peanut allergen of the 2S albumin family, 2010
Lipid transfer protein (Ara h 9) as a new peanut allergen relevant for a Mediterranean allergic population, 2009
Ara h 8, a Bet v 1-homologous allergen from peanut, is a major allergen in patients with combined birch pollen and peanut allergy, 2004
Isolation and characterization of two complete Ara h 2 isoforms cDNA, 2003
Molecular cloning and epitope analysis of the peanut allergen Ara h 3, 1999
Selective cloning of peanut allergens, including profilin and 2S albumins, by phage display technology, 1999
Recombinant peanut allergen Ara h I expression and IgE binding in patients with peanut hypersensitivity, 1995
Let me know if you found any of these interesting or useful.
If you spot an article or research that you think is interesting you can message me or tag me on Facebook or Twitter - links at the bottom of the page.