Food Allergies: Why They Occur
There are allergies that are more frequent in certain geographical areas and others that are more common in different areas; all this seems related to the eating habits of the local population. This is because the greater the consumption of a food, the greater the probability that we may become sensitized to it.
Allergy to rice , for example, is practically unknown in Italy and Europe, while it is very frequent in Asian countries, where the diet is almost exclusively based on the consumption of this cereal . The same goes for food allergy to peanuts , one of the most frequent in the United States where there is a high consumption of this food. In particular, its incidence is so high as to make it a real social problem (we are evaluating the possibility of inserting areas in public structures, such as airports, in which the consumption of peanuts is prohibited , since simple inhalation of food particles can favor the onset of the allergy). The same is also becoming very common in Europe and especially in northern countries.
Another example is given by kiwi allergy , once unknown in Italy but which has become frequent since the 1980s, when the food became part of the normal dietary habits of Italians.
Curiosity
The correlation between the frequency of food consumption in geographical areas and the appearance of food allergies has recently been misrepresented and exploited to justify the key principles of some “fashionable” diets. According to these nutritional stratagems, for too many centuries (actually millennia) human beings have assiduously fed on wheat , to which they have developed a metabolic-immune resistance . For this reason, with the aim of losing weight and fighting many wellness or inflammatory pathologies, it would be essential to eliminate many foods that are the basis of contemporary nutritional habits. For the moment, there is no scientific data to support this hypothesis.
| Foods most frequently implicated in allergic reactions in various countries around the world. | |
| Scandinavian countries | Fish allergy |
| United States | Peanut allergy |
| Mediterranean countries | Allergies to crustaceans and molluscs |
| Portugal | Snail allergy (typical national dish) |
| German-speaking Switzerland | Celery allergy |
| Italy | Allergy to celery, apple , kiwi, peach , nuts , peanuts, tomato |
Cross-reactivity
What cross-reactivity means and how to avoid it
Animals and plants that are phylogenetically close or belong to the same family ( goat and sheep or tomato and aubergine ) can have very similar DNA regions to each other. If these regions encode epitopic protein fractions, on which antibody recognition occurs, cross-reactivity is practically certain. This phenomenon explains why those who are allergic to tomatoes are often also allergic to aubergines or other nightshades, such as peppers .
Those who are allergic to a certain food must therefore also pay close attention to the consumption of similar foods from a phylogenetic point of view.
Hidden allergens
Beware of allergens hidden in foods!
In the food sector, soy lecithin is widely used which, due to its emulsifying properties , represents a typical ingredient in many food products . Those who are allergic to soy must therefore also be particularly careful about those products to which it is added as an additive in the form of derivatives (lecithin, but also protein hydrolysates).
This danger has required greater attention in the labeling of food products. The so-called allergen directive requires, for example, to warn the consumer of the possible presence of allergens, specifying it on the label . Thanks to this directive, it is not uncommon to find words such as “produced in a factory where dried fruit is processed” on the packaging. If the system has not been adequately sanitized before the conversion, it may happen that small residual particles contaminate the product, transforming it into a potential health risk for those who are allergic, for example, to peanuts .
Transgenic foods
Do transgenic foods contain more or fewer allergens?
In the preparation of a transgenic plant, DNA fragments from another botanical species are often inserted. If this DNA fragment codes for an epitope sequence, it may happen that the transgenic plant acquires an allergenic power, normally absent in its natural counterpart.
An example is that of transgenic soybeans . In fact, there have been cases of people who are not allergic to soy who have suffered an allergic reaction by eating it. It was later seen that this reaction was actually due to an allergy to the Brazil nut , whose DNA had been used for the production of transgenic soy.
With the ever-increasing spread of GMO foods, it becomes difficult for an allergy sufferer to understand what he can and cannot eat. All this to the detriment of his health, since an allergy is dangerous not so much for the food itself, but for the possibility of coming into contact, without knowing it, with the allergenic food.
Obviously the same principle can be applied in reverse; genetic research is also oriented towards producing new food varieties that DO NOT produce the sequences most often implicated in allergic reactions. Of course, this is far from a simple project to develop but, if it were successful, millions of consumers could finally enjoy those foods they have had to avoid from a young age.
