Currently, 20% of the population suffers from some type of allergy (including food allergies), and it is expected that by 2050 this figure will increase to 50%.

Food allergies are adverse reactions caused by substances present in foods that provoke an immune response. The immune system mistakenly identifies a specific food or substance in foods as something harmful.

Does this mean that anyone is susceptible to suffering from a food allergy? The truth is that there are a series of environmental and personal factors (genetics, microbiota composition, hygiene routines) that can cause greater hypersensitivity in the individual, causing the immune system to react to food allergens in an exacerbated way.

Approximately 250 million people worldwide suffer from some type of food allergy. It is estimated that they affect 5-8% of children and 1-2% of adults.

They should not be confused with food intolerances, as these do not involve the immune system. Rather, they occur when the digestive system has trouble processing certain foods or compounds due to a lack of enzymes or a sensitivity to specific additives.

A common example is lactose intolerance, in which the body does not produce enough lactase to digest milk sugar. The symptoms of intolerance are usually digestive (bloating, gas, or diarrhea) and, unlike allergies, are generally not life-threatening. While a food allergy involves an immune response that can have serious consequences, intolerance relates to the inability to digest a food without risk of anaphylaxis or serious harm.

Why is there this increase in food allergies?

We can divide the reasons into two large groups:

• Environmental factors such as excessive pollution, climate change, the massive use of detergents, disinfectants and other substances that instead of boosting our immune system, make it more reactive to any substance, and the accumulation of microplastics and other nanoparticles in the environment.
• Dietary factors such as the loss and modification of the microbiota biodiversity, caused by changes in dietary patterns that involve excessive consumption of fats and sugars and a decrease in the intake of antioxidant compounds and foods rich in vitamin D.”

Food allergies develop in two distinct phases:

• The first phase, known as sensitization, occurs when the immune system identifies a food as a threat and begins to produce antibodies (IgE) specific to that allergen. At this stage, the person does not experience symptoms, but their body is preparing for a possible future reaction.
• The second phase is the allergic reaction, which is triggered when the person is exposed to the same allergen again. At this point, IgE antibodies trigger the release of chemicals, such as histamine, which cause symptoms that can range from mild, such as itching and rashes, to severe, such as breathing difficulty and anaphylaxis.

It is essential to recognize these phases in order to properly manage allergies and avoid adverse reactions. The most recognizable symptoms of this type of allergy occur on the skin with redness or itching in the mouth or pharynx within minutes or a few hours of eating the food.

Rarely, other symptoms may appear several hours later, including:

• Tingling or itching in the mouth
• Hives, itching, or eczema
• Swelling of the lips, face, tongue, and throat or other parts of the body
• Wheezing, nasal congestion, or breathing difficulty
• Pain in the abdomen, diarrhea, nausea, or vomiting
• Dizziness, lightheadedness, or fainting

In some people, a food allergy can cause anaphylaxis, which is a severe allergic reaction and can lead to life-threatening symptoms. In cases of anaphylaxis, emergency treatment is essential, as untreated anaphylaxis can cause coma or even death.

Most food allergies are triggered by certain proteins in the following foods: Crustacean shellfish, such as shrimp, lobster, and crab, Peanuts, Tree nuts, Fish, Chicken eggs, Cow's milk, Wheat, Soybeans.

Countries with the highest prevalence of food allergies:

In the US, nearly 8% of children suffer from some form of food allergy, with a particular increase in allergies to nuts and peanuts.

In Australia, food allergies affect 10% of infants, with a notably high prevalence in children under five years old.

In Europe, some of the countries with the highest rates of food allergies are Spain, the United Kingdom and Italy. Spain has a high prevalence of allergies, especially to seafood and fruit, and this is attributed to the increase in consumption of these foods and environmental factors. In the United Kingdom, food allergy levels are also high, particularly in children, with peanuts and dairy being the main causes of severe reactions. In Italy, the incidence is significant due to the prevalence of allergies to fruits and vegetables, probably influenced by genetic and dietary factors that are part of the Mediterranean diet.

In Latin America, the study of food allergies is limited and data often vary between countries and regions. Mexico and Brazil lead the research in the region. In Mexico, a relatively high prevalence of sensitization to specific foods such as seafood and some types of fruit has been found, due to cross-reactions with common allergens in subtropical environments, such as mites. And in Brazil, although allergies to foods such as milk and eggs are also common, the variety of tropical fruits native to the country and their use in the diet may contribute to a different distribution of sensitization. In Colombia, Costa Rica and other countries in the region, studies indicate that nuts and corn also often cause allergic reactions in the population

New approaches to prevent and treat food allergies:

Recent studies have begun to explore innovative methods to prevent and treat food allergies, considering both biological and nanotechnological approaches. Among the most promising advances, oral immunotherapy (OIT) has shown efficacy in people who consume, under medical supervision, quantities of the specific allergen. This helps to desensitize the immune system gradually, decreasing adverse reactions to certain foods.

On the other hand, researchers at Northwestern University have developed nanoparticles that specifically target the cells responsible for allergic reactions without affecting other cells of the immune system.

Education after diagnosis is key to avoiding accidental ingestion of allergens, and today, the treatment par excellence is to avoid ingestion, inhalation or contact with the foods that cause the allergic reaction.

For many people with allergies, daily life involves reading labels, avoiding common foods, and preparing their own meals to reduce risks. This can complicate outings, trips, school and work environments, since it involves, in addition to managing a health condition, dealing with a series of emotional and social factors that affect life quality and integration into daily activities.

And in this sense, early diagnosis and the use of oral tolerance treatments in childhood are the best ways to ensure a better life quality in allergic adult individuals.