Are there more food allergies and intolerances than ever before?

BarcelonaRestaurant menus list, or at least make this information readily available, which foods may trigger an allergic reaction. This could include milk, fish, or eggs. We also see this in supermarkets, where the crossed-out wheat symbol, indicating that a product is gluten-free, is increasingly common. This paradigm shift is easily understood by looking at data from recent decades, which show that the immune system of the population, especially younger people, is changing. While allergy consultations in Spain numbered less than two million annually in 2011, by 2023 that figure had climbed to 16 million. Within this spectrum of illnesses, food allergies are experiencing the most rapid growth. Experts have also identified an increase in food intolerances, although they caution against distinguishing between the two phenomena and point out that, in some cases, there is insufficient evidence to determine whether someone is intolerant or not, attributing it to a growing trend. Maria Teresa Dordal, an allergist at Bellvitge Hospital and a member of the Scientific Advisory Committee on Food Safety in Catalonia, explains that allergies have an immunological component; that is, the body responds abnormally to food proteins. These can trigger immediate reactions after ingestion, such as hives or difficulty breathing, or delayed reactions, occurring three to four hours after eating. Of all the consequences, the most serious is anaphylaxis, a systemic reaction that can be life-threatening. In contrast, food intolerances are adverse reactions that occur when there is a condition that prevents the proper digestion of a food or one of its components. "In terms of the mechanism, they are very different," emphasizes pediatric allergist Mònica Piquer, coordinator of the complex food allergy unit at Sant Joan de Déu Hospital. Intolerance occurs when the body is unable to properly process or digest a food component. In this case, the immune system is not involved; rather, it is due to an enzymatic, metabolic, or digestive mechanism. The most common symptoms are digestive, such as stomach pain, diarrhea, vomiting, nausea, or gas, which can be very bothersome but do not pose a risk to the patient's life. Furthermore, they are dose-dependent, meaning that the greater the intake of the food in question, the more digestive symptoms the person experiences, says Piquer.

Most frequent foods

In Catalonia, the most common food allergens in children are milk, eggs, and fish, while in adults they are peaches (or other peach-like fruits), nuts, and shellfish. The most frequent intolerance, however, is to lactose, the sugar in milk, which occurs when there is a lack of the enzyme responsible for breaking it down. Other foods that cause less frequent intolerances include sorbitol, fructose, and histamine, explains Dordal. Currently, consumer information regulations require the declaration of the 14 allergens responsible for the majority of food allergies in the European population. The aim is to prevent the inadvertent ingestion of small amounts or traces from causing potentially serious allergic reactions. Food intolerances can be temporary or more persistent, but allergies are lifelong. Only if the allergy is introduced at a young age, such as with milk or eggs, for example, can tolerance be developed over time. For years, experts believed that to avoid allergies it was necessary to delay the introduction of problematic foods, but Piquer assures that the key is early exposure. For example, between 4 and 6 months of age, there is a "window of opportunity" to introduce hard-boiled eggs in small quantities or nuts continuously, thus teaching the body that these foods are not enemies. However, the expert emphasizes that once a food is introduced, it should not be discontinued; "continuity is key."

For those who have already developed the allergy, at Sant Joan de Déu Hospital they work with oral immunotherapy: "We give small doses so that they develop resistance, seeking a safe dose," explains the pediatrician. The treatment consists of administering controlled minimum doses to raise the patient's safety threshold and prevent severe, life-threatening reactions in the event of accidental ingestion. While factors such as climate change and pollutants continue to drive the upward trend in allergies, the medical response now focuses on active prevention and health education to improve the quality of life for these patients.

Trends and Confusion

Dordal clarifies that there is no way to prove the vast majority of food intolerances, which is why she says diagnosis is complicated. Therefore, she argues that simply eliminating a food from the diet and seeing that digestive symptoms disappear is not enough to confirm a food intolerance. The improvement could be attributed to other changes, so the expert maintains that the food should be reintroduced into the diet to see if the symptoms reappear, and that this should be done under the guidance of professionals. An example, she says, is gluten, since many people currently come to the clinic claiming to be gluten intolerant without having been tested.

Here, Irene Puig, spokesperson for the Celiac Association of Catalonia, emphasizes that there is a lot of confusion between the concepts of celiac disease, wheat allergy, and gluten sensitivity. On the one hand, celiac disease is a multisystemic autoimmune disorder that causes atrophy of the villi in the small intestine, affecting the body's ability to absorb nutrients from food. On the other hand, non-celiac gluten sensitivity, also popularly known as gluten intolerance (although Puig maintains that this is a misnomer), was first described in the late 1970s, but has only recently begun to be recognized and has been intensively studied since 1970. Finally, there is wheat and other cereal allergies, which are an immune system response. Another intolerance that is said to be "in vogue" is small intestinal bacterial overgrowth, or SIBO, which consists of an abnormal presence of bacteria in the small intestine, explains the expert. When carbohydrates or sugars are ingested, bacteria carry out a fermentation reaction in the small intestine, generating an excessive amount of gas that causes digestive problems such as bloating, gas, or diarrhea. However, the expert warns that other diseases and imbalances in the gut microbiota can also cause similar symptoms. Therefore, Dordal insists that it is always necessary to consult an expert and that people should not become obsessed with food.

Nevertheless, the experts also acknowledge that diagnostic capacity and social awareness surrounding food intolerances have greatly increased, and people are paying much closer attention to what they eat. Previously, many of these digestive discomforts went undiagnosed. Allergies, meanwhile, are increasing exponentially and pose a challenge to public health. For this reason, they argue that it is necessary to improve education about these two phenomena from childhood to differentiate between vital needs and a passing fad.