About three in a hundred patients food allergy they’re to the garlic and onionsvery common and important bulbs in our diet, according to a new study that shows for the first time the incidence of these foods in a large sample of allergic patients and describes the associated clinical symptoms.
Dr. Alicia Armentia, professor at UVa, head of the Allergy Unit at Río Hortega University Hospital in Valladolid and lead author of the study, explains to DiCYT that despite Spain being one of the world leaders in the consumption of edible flower bulbs , (garlic and onion), in the existing scientific literature there were few references to its ability to cause allergic symptoms.
In fact, in the standard battery of allergens applied to patients attending allergy consultations – including 44 common allergens, such as wheat, milk, eggs, cereal, fruits, vegetables or spices – these foods are not included. “Sometimes we have observed allergies associated with common foods, but when running the battery we had no positive results for any of these allergies. That is why we have decided to… garlic and onion in the tests,” says the researcher.
Food allergies: garlic and onion in standard tests
For example, over the course of a year, garlic and onion were included in the standard tests, skin tests and blood analytical determinations carried out on all patients seen in consultation, more than 8,100 people. A total of 356,000 skin tests and 4,254 blood antibody determinations were carried out.
The team found that 30.92 percent (2,508 patients) showed symptoms related to food intake and then detected food sensitivities in 924 of them using a specific skin test. In 27 cases, the allergy was caused by garlic and onion, which amounts to a prevalence of 2.92 percent.
Food Allergies: What Allergen Do Garlic and Onion Have?
Once the prevalence was estimated, the team investigated which specific allergen was present garlic and onion caused these symptoms and food allergies. “Garlic and onion contain many different proteins and other irritants. We conducted a molecular study and discovered that the allergen that affected all patients was common, a natural antifungal agent from these bulbs,” explains Armentia.
To survive the fungi, bacteria, viruses and mites that attack them, garlic and onions They defend themselves with antifungal proteins called LTPs (lipid transport proteins). LTPs, which are also present in many other foods, are very important as allergens because they are associated with very serious symptoms, such as anaphylaxis, which can be fatal if the affected person is not treated immediately.
“In our Mediterranean region, the LTP that we most often see as a cause of anaphylaxis is that of peaches. But there is also that of wheat and seeds in general. These are plant foods that are strongly attacked by fungi and have to defend themselves,” says the researcher, who puts this forward in the case of garlic and onion the LTP that causes allergic reactions is different, specific to these lamps.
For all these reasons, the researchers emphasize in their article that allergic hypersensitivity to garlic and onion should not be underestimated and, given their high consumption, should be included in the diagnostic battery of food allergy.
In this sentence, Dr. Armentia the case of a one year old girl with symptoms of food allergy of unknown origin. The little girl did not ingest garlic, but her mother did, and the allergen was passed to her through breast milk. “The girl had anaphylaxis and we didn’t know why. And eventually we discovered it was the garlic,” he recalls.
Researchers have also observed other symptoms associated with diabetes food allergy, such as digestive complaints – diarrhea and abdominal pain -, asthma, rhino-conjunctivitis – especially in people who work in the kitchen – and skin complaints, especially in the left hand. “When you cut garlic or an onion, you hold it with that hand. And if the index, thumb and middle fingers are affected, that is a clear indication the allergy could be to garlic and onion”, concludes the expert.