f35 Potato

Potato (Solanum tuberosum L.) belonging to the Solanaceae family, is the third-largest cultivated crop in the world. It’s a herbaceous plant grown in humid and temperate climate areas around the world. Large population studies in France, Germany and Korea have reported the prevalence of potato allergy to be 10.1%, 19.3% and 5.7% respectively. Studies have shown that consumption of potato by allergic patients will result in the adverse reaction such as bronchial asthma, allergic rhino- conjunctivitis, and atopic dermatitis. A study reported among individuals with potato allergy, 4.7% suffered from asthma, 11% from allergic rhino conjunctivitis and 14.4% with atopic dermatitis. To avoid suffering from a food allergy, complete abstinence from such foods is advised. Sol t 1 (Patatin) has been documented as a major allergen, with infant studies reporting 75% of the patients allergic to potato having specific-IgE against Sol t 1. Cross-reactivity between potato, tomato, latex and birch pollen has been reported. 

Nature

Potato also is known as Solanum tuberosum L. is the food crop of paramount importance worldwide which comes in the third position just after wheat and rice.(1) It is an herbaceous plant with a height ranging from 0.4 m to 1.4 m which may grow either horizontally or vertically. Its stem has a base of width approximately 5 to 19 mm, smooth or densely rough surface, and greenish in color. It has sympodial branching with a trifoliate or plurifoliate structure that does not germinate (2). 

Habitat

Potato is cultivated in all regions around the world. It is cultivated in about 150 nations around the world with humid and temperate climate regions. (1) It does not favor elevated temperatures for good production. For this reason, it is grown at cold upland regions in the tropical areas whereas in the sub-tropical regions at the medium elevated areas in the cold seasons. Besides, in the areas with high temperatures, it is grown in downhill regions. Its cultivation is usually seen in the temperate areas of Europe (3).

Taxonomy

Worldwide distribution

A large population study was conducted in France for understanding the allergy and sensitization prevalence towards potato. The study stated from 20,000 subjects 10.1% were sensitized to raw or cooked potato.(5)  A German study evaluated the prevalence of food allergies and related adverse reactions in their population of 13,300 residents in Berlin. The study stated 2298 individuals with food allergies were reported and among these 19.3% patients were found to have positive reaction to skin prick test for raw potato.(6) In Korea a study was conducted on 1888 allergy patients, wherein 108 (5.7%) patients undergoing skin prick testing reported positive response towards wild and genetically modified potatoes.(7, 8)

Risk factors

In one survey conducted to know the temporal association of asthma and associated risk factors in Chile (South-Santiago), excessive consumption of potato (and meat) was associated with episodes of asthma (9). Another study was conducted in Germany to compare the prevalence of bronchial asthma, allergic rhino-conjunctivitis as well as atopic dermatitis with allergic sensitization to specific IgE antibodies in children and adolescent population. The results found a statistically significant association with potato allergen by a total of 8.4 percent in the weighted sample of 1059 subjects (10).

Pediatric issues

A study in some infants and young children found that exposure to cooked potatoes resulted in severe allergic disease with symptoms of immediate hypersensitivity and/or atopic dermatitis (11) In one report, an anaphylactic reaction occurred in an infant aged of 5 months immediately after eating cooked potatoes (12). In another report, atopic eczema developed after eating cooked potatoes in infants. (13, 14). In another report, a 4-years-old child developed urticaria after coming in contact with the pulp of raw potato (15). 

Worldwide distribution

The potato plant is cultivated all around the world now. It is believed to have originated from South America. It was then grown in European nations such as England and Spain in the late 15th century. It was cultivated from Venezuela to Argentina and subsequently to the Chile islands. Later it was introduced in Mexico, central parts of the United States, India (particularly in the hills of Shimla) as well as the Canary Islands (1, 2, 16). In the year 2007, the highest producers of potato in the world were China, Russia, and India. Potato is produced more in North America due to factors like cold temperature with heavy rain, advanced machinery, use of pesticides and fertilizers, planned crop rotations (16). The developing nations such as India produces about half of the world-supply of potato which is a staple food for more than a billion population (1).

Main

Potato allergy occurs mainly through ingestion route. In individuals contact with raw potato has been found to result in oral contact dermatitis (17). 

Allergic rhinitis and Allergic Rhino-conjunctivitis (ARC)

A study was conducted in Germany to compare the prevalence of bronchial asthma, allergic rhino-conjunctivitis as well as atopic dermatitis with allergic sensitization to specific IgE antibodies in children and adolescent population. The results found a statistically significant association with potato allergen (8.4%) in these populations.  The lifetime prevalence of asthma, allergic rhino-conjunctivitis, and atopic dermatitis in these populations was 4.7%, 11%, and 14.4% respectively (10).

Asthma

A survey was conducted to know the temporal association of asthma and risk factors in Chile. In this survey, it was found that from the year 2002 (30.5%) to 2015 (22.5%), excessive intake of potatoes was associated with a higher risk of asthma episodes (p=0.031) (9).

Atopic Dermatitis (AD)

A study was conducted on young children and infants with suspected food-based allergy and AD. The study reported atopic eczema symptoms developed after eating cooked potatoes in infants(age below 1 year)(13, 14).

Other topics

Oral allergy Syndrome

In adult patients, the allergic reaction to the raw potato is often described as a manifestation of a condition known as oral allergy syndrome (OAS) in individuals with an allergy to pollens. This is common in individuals such as housewives who encounter reactions such as contact urticarial (itching), rhino-conjunctivitis, and, in a few instances, asthma (wheezing) while peeling the potatoes. (11)

Anaphylaxis

In one report, an anaphylactic reaction occurred in an infant aged 5 months just after eating cooked potatoes. In another report, a 4-years-old child developed contact urticaria with raw potato. (13) (18)

In vitro diagnostics

In one study conducted in 1886 patients with different allergic conditions and healthy controls, skin-prick testing and IgE-ELISA test were used from the extracts of wild-type and genetically modified (GM) potatoes. Serum-specific IgE levels were detected in up to 88% of allergic individuals (n=108). The analysis of IgE-immunoblot showed the presence of 14 IgE-binding components in the wild-type potato and 9 in the GM group of potato. Also, a common 45-kDa binding component that produced the same IgE-binding pattern was found in more than 80% of the reactions by utilizing sera of the individuals sensitized to wild-type or GM potato (8).

Avoidance

The main strategy to avoid food allergy is to completely abstain from such foods (19). In one study, cooked potato was used as an allergenic food in children with atopic dermatitis. A total of eight atopic children were included in this study. Seven out of them were challenged with cooked potato. There was a reduction in the severity score after the elimination of potato from the diet in these children (11).

Allergenic molecules

Potato contains numerous allergens. “Patatin” (Sol t 1) is a heat-labile glycoprotein allergen of paramount importance. The significance of patatin as a main potato allergen is supported by the ELISA inhibition test on four serum samples extracted from potato-allergic children. In each serum sample, the binding of IgE against the total protein extract of potato was significantly inhibited by Patatin. (20) Other potatoes IgE binding allergens identified are Sol t 2, Sol t 3 (isoallergens Sol t 3.0101 and Sol t 3.0102) and Sol t 4, they also belong to the soybean trypsin inhibitor family (20).

Biomarkers of severity

It has been documented that heat-stable allergen Sol t 1 is a clinically significant food allergen in atopic infants who have a positive reaction to SPT for the raw potato. Specific IgE antibodies to Sol t 1 were evidenced in 75% (9 out of 12) of the infants suspected of being allergic to potato and suffering from atopic dermatitis. (13) In the ELISA test, specific IgE-binding to the allergens such as Sol t 2, Sol t 3.0101, Sol t 3.0102 and Sol t 4 was observed in 51%, 43%, 58%, and 67% of the children suspected of potato allergy (21). 

Cross-reactivity

In adult patients, raw potato hypersensitivity reaction is believed to occur due to IgE cross-reactivity with pollens of birch, grass, or mug-wort. (11) Several studies have shown that allergy to natural rubber latex is associated with cross-reactivity to certain foods such as tomato and potato. A study showed that potato, tomato, and latex contain a common band sequence of molecular weight 44-46 kDa and this band may be patatin protein. Also as observed during immunoblot and CAP inhibition testing this protein may be responsible for the high cross-reactivity between potato, tomato, and latex  (22).

Author: Turacoz Healthcare Solutions

Reviewer: Dr. Fabio Iachetti

Last reviewed: October  2020