The reason why more and more people have allergies to meat

More and more people claim to have allergies to any food, and proof of this is the obligation to report on the presence of allergens in nutritional labels and in restaurant charts. But one thing is what we perceive and the social concern that exists on this matter and another is reality. If we stick to the objective data, the prevalence of food allergy is maintained between 1% and 3% of the general population, as in 2004, according to the report Alergológica 2015, prepared by the Spanish Society of Allergology and Clinical Immunology ( Chapter 8), which does admit that there may indeed be an increase in allergies although it has not been demonstrated.

Fruits (for 44.7% of food allergies), nuts (28.4%), shellfish (14.8%), milk (11.2%), fish (10%) and eggs (9.8%) are at the point of view of many people, who flee from them because a simple bite provokes an attack that Virtually stays in a skin reaction, itching in the mouth and digestive discomfort (annoying but not serious), although for 12% of affected people who have an anaphylactic reaction are a vital threat.

Lovers of hamburger, steak or any cut of veal, ox, pork or lamb breathe calmly because, who knows a meat allergy? Yes, there are and more and more, especially in the United States, but in other countries, such as Sweden, France, Japan and also in Spain, there are allergic to meat, with the aggravating factor that while the reaction to the most common allergen food happens to the few minuts Eating them, the symptoms of meat allergy (urticaria, anaphylaxis, angioedema) are delayed for hours, from 3 to 6, making it difficult to relate the hamburger with itching and ronchones.

Therefore, immunologist Thomas Platts-Mills, University of Virginia (USA), and one of the leading investigators on this allergy warned in the Journal of Allergy and Clinical Immunology that physicians need to know that peculiarity of Delayed reaction to prevent very serious consequences.

The issue of beef allergy in the United States since the Decade of the 90 without knowing why people who were accustomed to eating meat one day stopped toleratingit. Meanwhile, Platts-Mills investigated in his laboratory why some patients treated with cetuximab — a monoclonal antibody used for advanced colorectal cancer — developed an allergic reaction, and detected that all Allergic to the drug had IgE antibodies to alpha-gal (a type of sugar linked to meat proteins from non-hominid mammals).

In a new investigation, the immunologist crossed the data of the allergic to the cetuximab with those of allergic to the meat and found that they all belonged to an area of the Rocky Mountains in which people were infected with a fever, a disease transmitted by the Lone Star tick bite (Ammblyoma americanum). Soon thereafter, Platts-Mills and two other members of his team developed meat allergies and that's when, Eureka!, They found a common link: everyone who showed allergies (the drug and the meat) had bitten a tick.

José de La Fuente, research professor at the CSIC of the Health and Biotechnology Group of the Institute for Research in Hunting resources, has published several research on this issue and confirms that "the origin of the allergy to red meat is the Tick sting, which promotes an immunologic response that may not always result in the development of anaphylaxis to red meat consumption. " The explanation for this fact is that "hominids, including humans, evolve by losing the ability to produce alpha-gal carbohydrate and the only contact we have with this naturally is intestinal bacteria."

In other words, we are accustomed to contact with this meat sugar by the digestive tract and "the normal response is tolerance", explains Moisés Labrador, president of the Immunology Committee of the Spanish Society of Allergology and Clinical Immunology (SEAIC). . But when a tick bites "the contact is transdermal with the saliva of this mite" and then it can courrir a delayed anaphylactic reaction (3 to 6 hours after ingestion of red meats).

In Spain it is more common in the Cantabrian and Atlático areas than in the Mediterranean

The mechanism by which the tick bite modifies the immune response to a type of response that leads to the development of anaphylaxis from red meat consumption "is not discovered," says the CSIC researcher, but there is no doubt that one thing It's a consequence of the other.

Spain does not get rid of this threat. In fact, "We have reports of individuals who have elevated levels of IgE antibodies to alpha-gal [sugar] that can lead to anaphylaxis from red meat consumption. the risk is real and not associated with a single species of tick, "he adds. "It is a problem known to allergists and can be diagnosed anywhere in Spain. There are cases described of anaphylaxis retarded by meats especially in Galicia and all the Cantabrian and Atlantic cornice, "confirms the representative of the SEAIC. "In the Mediterranean area it seems to be less frequent."

In America the most problematic are the grilled burgers; Here, the pig kidneys

The type and way of preparing the meat also influences the appearance of the symptoms, according to the immunologist. Thus, "in the United States it is mainly associated with grilled hamburgers and in Spain, with pig kidneys. Although patients may have different sensitivity depending on the number of bites, the greater the number of bites the higher IgE levels to alpha-gal and the more possibility of allergy with more different meats. "

The message of the specialists is of tranquillity, that does not mean that it is necessary to underestimate the risk. For the representative of the CSIC it is "an emergent problem, while there are different factors, such as the fact that some species of ticks are spreading in some regions, and also that we have more and more contact with ticks Because we go more to field areas where they live. " Moreover, it should be counted that until recently this problem "was not identified and nobody associated that elevated levels of antibodies against alpha-gal with anaphylaxis".

And given the link encountered with the cetuximab, Labrador points out that "we should ask all patients to be treated with this monoclonal antibody if they have ever bitten a tick, and if the answer is affirmative, measure the levels of IgE to Alpha-Gal ".

If you are bitten by a tick do not try to seized it like a mosquito

Once the danger is identified, the important thing is to protect yourself: go to the field with long trousers, check the pets after walking through wild areas and use Acaricides. José de la Fuente stresses that if we find a tick in a person or an animal, "do not try to tear it or tighten it because it can inoculate all the poison it has. It is best to remove them with tweezers, grasping at the point of attachment to the body. Never try to get rid of it like a mosquito. " Zquí we explain how to treat this bite and the insect bites and other animals that you will encounter this summer.

So, having an outbreak of meat allergy implies saying goodbye forever to the pleasure of eating a hamburger? The experts differ. De La Fuente, of the CSIC, believes that Yes and argues: "We do not know the mechanism that leads people to develop allergies and others do not. There are many questions in the air, so it is best to avoid eating red meat. "

The allergist Labrador believes that "after a few years the IgE to alpha-gal may disappear and that person can return to eat a hamburger, as it happened to Platts-Mills." However, "someone who has presented a delayed allergy after eating red meat should consult a allergist to confirm or discard the diagnosis," he advises.

For them, there is still the option of eating poultry, for which, for now, there is no record of food allergies.