Football is the most popular sport worldwide, and the Fédération Internationale de Football Association (FIFA) has been its main governing body, overseeing and promoting its development at all levels. Its central event is the FIFA World Cup, a tournament whose growth has steadily increased global viewership, sponsorship, and economic impact in host countries.^1,2

The FIFA World Cup is held every four years, and the 2026 edition will be the first organized by three countries (Mexico, the United States of America, and Canada). A significant number of visitors is expected in Mexico, predominantly men aged 18 to 44, coming from regions such as South America, East Asia, and Central Europe.³ It is estimated that fans will stay for approximately 12 days, spending an average of $416 USD per day, with nearly 30% of this budget allocated to food.⁴

During the 2026 FIFA World Cup, it is likely that many visitors will consume traditional Mexican cuisine.⁵ Although this represents a cultural opportunity, it also poses a challenge for individuals with food allergies, particularly when exposed to unfamiliar local ingredients. In this scenario, food education, clear labeling, training for food staff, and the preparation of the health system become especially relevant.⁶

A food allergy is an adverse immunological reaction triggered by proteins present in seemingly harmless foods, which occurs in susceptible individuals.⁷ Manifestations can appear immediately and range from mild symptoms (oral pruritus) to severe anaphylaxis, particularly in previously sensitized patients.⁸

Anaphylaxis is the most severe manifestation of allergy; symptoms typically appear within the first 30 minutes after consuming the allergen and include manifestations in at least two systems, including: cutaneous (urticaria, pruritus, angioedema), digestive (abdominal pain, nausea, vomiting, diarrhea), respiratory (wheezing, laryngeal obstruction, rhinorrhea), and/or hemodynamic (hypotension, syncope, tachycardia)(9); therefore, it represents a potentially life-threatening condition and is resolved by the administration of intramuscular adrenaline (0.5 mg) (0.5 mL from a 1 mg/mL ampoule, the only presentation available in Mexico).¹⁰

Food allergy is a major public health problem that affects all aspects of life, and travel is no exception.¹¹ The prevalence of food allergy is approximately 10% worldwide.¹² Furthermore, various allergens show cross-reactivity with a wide variety of foods, increasing the risk of exposure during international travel.¹³

Travelers with food allergies may experience allergic reactions at any stage of their journey. For example, it has been reported that the prevalence of food-related allergic reactions during flights varies ~3%, while the prevalence of reactions occurring during the trip increases to 10%. Likewise, most of these manifestations occurred in countries where the predominant language was not English.¹⁴

Various food reactions are explained by cross-reactivity, that is, the recognition of shared epitopes between different allergens by the same IgE antibody. Molecular sensitization corresponds to the coexistence of specific IgE antibodies directed against individual molecular allergenic components (genetically and immunologically defined proteins), detectable through in vitro tests.¹⁵

Based on the above, the objective of the study was to describe the main allergens identified in native Mexican foods, particularly from the milpa diet, that could represent a potential risk for travelers or fans with food allergies in the context of the 2026 FIFA World Cup in Mexico, with the intention of providing useful information for first-contact physicians and subspecialists to establish an timely diagnosis.

Méthodology

A descriptive and retrospective study was carried out based on a bibliographic search in the United States National Library of Medicine (PubMed), using combinations of terms related to each food of the milpa diet and food allergy, with the keywords: “X-food of the MILPA-D (scientific name) AND food allergy”; [for example, Solanum lycopersicum (tomato) AND food allergy]. Articles from 2002 to 2025 were included, with an emphasis on plant-based foods, the main group that constitutes the milpa diet. Subsequently, only those that had an allergen described in the World Health Organization/International Union of Immunological Societies (WHO/IUIS) database were selected and, in turn, were classified by protein families. Finally, a descriptive analysis of the most frequently identified proteins was performed, and the results were expressed in percentages. Supplementary Figure 1

The “milpa” diet consists of 71 foods, and 51 of these have food allergy reports; however, at least one allergen was identified in only 13 vegetable foods: peanut, tomato, sunflower seeds, corn, pea, lentil, pumpkin, chili, papaya, pineapple, amaranth, green bean, and avocado. Figure 1

The most relevant protein families in vegetables were profilins, present in eight foods (peanut, tomato, sunflower seeds, corn, chili, pineapple, green bean, and amaranth), followed by nonspecific lipid transfer proteins (nsLTP), identified in seven foods (peanut, tomato, sunflower seeds, corn, pea, lentil, and amaranth), and PR-10, present in two foods (peanut and tomato).

Additionally, a broad group of other allergenic proteins was identified (n = 36 proteins in 13 foods), mainly: endo-polygalacturonase in papaya, 2S-albumin in peanut, bromelain in pineapple, beta-fructofuranosidase in tomato, and vicilin in lentil. (Table 1)¹⁶ 38.46% (5/13) of the foods shared at least two allergenic proteins. In particular, peanut and tomato shared the three main families described (2/13; 15.38%), while sunflower seeds, corn, and amaranth shared profilins and nsLTP (3/13; 23.07%). Supplementary Figure 2

In this descriptive analysis, profilins were the most frequent protein family in the foods of the milpa diet with identified allergens. These proteins are found in widely consumed and easily accessible foods, such as peanut, tomato, sunflower seeds, corn, chili, pineapple, green bean, and amaranth, which increases the probability of exposure in the local population and among tourists or fans.

Food allergy is a disease whose incidence has increased. Although milk and egg are among the most prevalent food allergens worldwide, various fruits, tree nuts, and peanuts also represent relevant sources of sensitization and clinical disease.¹⁷

In the present analysis, profilins and PR-10 stood out for their frequency. Both protein families are usually thermolabile and susceptible to digestion, so they have been associated mainly with mild manifestations: pruritus and edema in the lips, tongue, palate, and pharynx, in the context of oral allergy syndrome (OAS), which can appear after the consumption of raw fruits-vegetables in previously sensitized patients, although the risk of systemic reaction with these proteins is extremely low.^15,18,19 However, it is important to mention that, although several foods share common antigenic determinants, this phenomenon is not necessarily related to any allergic clinical manifestation.²⁰ In Mexico, various foods containing these proteins are consumed as snacks, traditional sweets, or ingredients commonly used in sauces, salads, and other preparations.

On the contrary, nsLTP are more stable proteins to heat and digestion, so they can induce reactions, even after cooking, and have been related to systemic reactions.²¹ In this context, peanuts and tomatoes acquire special clinical relevance, because they are part of widely consumed preparations, including sauces and other typical dishes. Although peanut proteins were not of high frequency in this study, they represent one of the most relevant allergens worldwide, and have been related to systemic reactions (anaphylaxis), which is important because it is incorporated into a great variety of foods in Mexican culture.^22,23 Figure 2A

In Mexico, the ingestion of insects is common, for example, crickets, scorpions, ants, escamoles (ant eggs), and acociles (crustaceans), foods that are very attractive to foreign visitors; however, many of these contain tropomyosin (a protein related to anaphylaxis), which, despite not being a protein group evaluated in our analysis, the identification of this protein poses a risk in susceptible patients with previously known shrimp allergy, due to the probable phenomenon of cross-reactivity between these species.²⁴ Figure 2B

A significant proportion of the analyzed foods shared more than one allergenic protein family.²⁵ This finding supports the possibility of cross-reactivity or concomitant sensitizations in susceptible individuals. For example, patients allergic to apples could also be allergic to carrots, due to the presence of PR-10 and/or profilins,^13,26 and this may suggest susceptibility to tomatoes when consumed raw.

In international events, such as the 2026 FIFA World Cup, tourists face an environment of great cultural and gastronomic diversity, which increases the probability of exposure to unfamiliar allergens. Therefore, it is essential to strengthen health education and promote specific preventive strategies for travelers with food allergies.¹¹ Figure 3

The present search focused mainly on foods of plant origin, due to their wide distribution in local foods and frequent incorporation into typical dishes, where their identification may not be evident to the tourist. This characteristic justifies the relevance of the approach adopted in our study. However, a limitation of this methodology is that the analysis of allergens or protein families contained in each food depends on the existing information in the WHO/IUIS database, which is updated intermittently and considers only validated allergenic proteins for consultation.

This research seeks to provide useful and accessible information for first-contact physicians and fan patients with food allergies who will travel to Mexico during the 2026 FIFA World Cup. Although the milpa diet is recognized for its nutritional value and metabolic and cardiovascular benefits, the foods can contain proteins with allergenic potential in susceptible individuals.^26,27

In this context, it is recommended that travelers attending the 2026 FIFA World Cup with a diagnosis of food allergy identify nearby health services near the main sports venues in advance, and request detailed information on the ingredients and preparation of dishes, given the impossibility of preparing their own food.¹⁷ In particular, it is advisable to take extreme precautions with foods containing nsLTP: peanut, tomato, sunflower seeds, corn, pea, lentil, and amaranth, due to their possible association with systemic reactions in previously sensitized patients and, therefore, with greater susceptibility.

Regarding labeling rules in Mexico, NOM-051-SCFI/SSA1-2010 establishes that the identification of allergens must be declared in a mandatory and visible manner on the label of manufactured products with the phrase “may contain”.²⁸ However, it is important to mention that, in foods prepared in restaurants, markets, or on the public street, this identification may be limited, which represents an additional risk for tourists with food allergies at the time of consumption.

It is important to comment that among the main challenges for travelers with food allergies are language barriers, so effective communication is also key. Among the safety strategies when consuming food abroad are: 1) always ask about ingredients and the method of preparation, 2) notify the allergy in restaurants, 3) use translation cards in the local language, and 4) avoid environments with a high risk of cross-contamination (buffets). Additional measures, for example: carrying safe food during travel and cleaning contact surfaces, can also contribute to reducing complications.

Within the foods included in the “milpa” diet with identified allergens, profilins were the most frequent protein family; therefore, they may be primarily associated with local manifestations. However, some widely consumed foods also showed nsLTPs or tropomyosin, protein families of greater clinical relevance related to systemic reactions, including anaphylaxis. Together, these findings provide useful information to guide travelers with food allergies visiting Mexico during the 2026 FIFA World Cup, as well as for the physicians involved in their care.