Genetics of food allergy and intolerance

Can genetics explain if you are allergic to some pollen or food?

Genetically determined white blood cell models and designated as HLA DQ and DR genes have been identified with an increased risk of pollen, dust, latex and food allergies. The interesting part of this story is that there is an advantage in knowing your type of DR and DQ HLA when evaluating the risk of pollen allergies and their food allergies or associated cross-reactions.

Genetics of food reactions and allergies

As I explain in more detail in my articles on the genetics of gluten sensitivity, we all have proteins on the surface of our cells that are genetically determined. These patterns are easily detected by testing the cells from the blood or mouth obtained with a Q-tip type buffer. Specific models have been associated with an increased risk of autoimmune diseases, sensitivity to gluten and celiac disease.

HLA DQ Genetics and Celiac or gluten sensitivity

HLA DQ2 is present in over 90% of people who have celiac disease while HLADQ8 is present in most others, although not all people with celiac disease have DQ2 and / or DQ8.

DQ and DR genetic models associated with allergies or food and pollen sensitivities?

It now appears that some DQ or DR schemes are also associated with food and pollen allergies. As a Food Doc, I continue to search the literature for more information on genetic links to food allergy and intolerance. My research led me to a couple of interesting articles in the unusual area of ‚Äč‚Äčoral allergy syndrome (OAS). The relationship between seasonal and perennial nasal allergies and food allergies is certainly well established but generally not known by most doctors or patients. It seems that some of us should avoid eating certain foods if we have hay fever or allergies, especially during the hay fever season. This problem also seems to be inherited.

Research papers Genetic association with some food and pollen allergies

Boehncke, et al. University of Frankfurt reported in 1998 that certain types of white blood cells known HLA class II genotypes or HLA DQ and DR genetic models were found more frequently in people with certain food allergies associated with pollen. HLA-DQB1 * 0301 is present in more people with grass pollen allergy. Those with HLA-DRB1 * 08, a hereditary model of white blood cell protein associated with an allergy to grass pollen, have a six times greater risk of peanut allergy. Those who inherited the HLA-DRB1 * 12 white blood cell model have a 13 times higher risk of carrot allergy.

Tree Pollen Birch Allergy Pollen looks worse

The hazelnut allergy associated with birch pollen is linked to HLA-DRB1 * 01, DQA1 * 0101 and DQB1 * 0501. Hazelnut, almond, walnut and apple are the most common food allergies associated with birch pollen. Allergies to these foods are commonly associated with birch pollen in other studies.

Weed allergies also associated with food reactions

In 2004, Wang et al. from China, it published that hereditary white blood cells of type DQA1 * 0302 are found in more people with Artemisia pollen-induced allergic rhinitis, hay fever due to mugwort or sage weeds. Mugwort allergy is associated with several food allergies including apple, celery, hazelnut, pistachio, lettuce, almonds, peanuts and carrots.

Where to get genetic tests

I am aware of three commercial labs that offer full HLA DQ typing. They are Quest Laboratories, The Laboratory at Bonfils in Denver and Enterolab. Bonfils performs Enterolab genetic tests. Enterolab offers testing on cell samples obtained from a Q-tip swab of the mouth. The test can be obtained directly from Enterolab without a doctor’s order, although it is not covered by insurance. However, it is very reasonable from a genetic testing point of view at $ 149. Bonfils also performs DQ typing on cells obtained from blood samples sent from other laboratories.

The future of genetic testing in pollen and food allergies

In the future, such tests should be very useful in evaluating suspected food allergies, intolerances and allergies to pollen. In the meantime, those of us interested in this interesting story are eagerly awaiting further research results in this exciting area. Enterolab founder Dr. Fine previously published HLA DQ models associated with microscopic colitis. He found that microscopic changes in the colon or large intestine are similar if not identical to those observed in the small intestine in celiac disease. Numerous articles now document that a gluten-free diet works in many people with microscopic, lymphocytic and collagen colitis. It also helps many with Crohn’s disease and ulcerative colitis.

A discovery of intraepithelial lymphocytosis in the distal small intestine (terminal ileum) is associated with an increase in the incidence of celiac disease in the proximal small intestine. Now, adding to the intrigue, these articles link certain hereditary genetic models of white blood cell protein proteins to pollen allergy and food allergy cross reactions that are well recognized but rarely clinically pursued. Oral allergy syndrome (OAS), also called “burning mouth syndrome”, occurs in many people but is often not diagnosed. Symptoms include burning sensation, pain and / or itching in the mouth or throat with or without swelling which occurs almost immediately after eating certain foods. The foods that cause these reactions are commonly associated with pollen, latex or dust allergies.

Unusual association of pollen allergies and burning in the mouth or food reactions

This unusual association of pollen from trees, grass and weeds, latex and house dust mite allergies to food reactions, although well documented in the medical literature, is not commonly recognized by doctors or patients. The OAS literature contains numerous reports of food allergies or intolerance reactions associated with specific allergies to pollen, dust, mold or latex. One of the best examples is ragweed pollen allergy. It is associated with an increased risk of allergy or food intolerance to few foods. These include foods from the pumpkin family (cucumbers and melons) and bananas. On the other hand, birch pollen allergy is associated with sensitivity to many foods. The list includes those foods from the Rosacea family (apples, pears), the nut family (hazelnuts, almonds, walnuts), potatoes and carrots. Reactions include classic allergic reactions such as skin rashes (atopic dermatitis, urticaria), wheezing (asthma), runny nose (allergic rhinitis), symptoms of burning mouth OAS and other symptoms of food intolerance.

If you suspect allergy, intolerance or food sensitivity, be evaluated by an expert

Individuals who suspect food allergies or intolerances are encouraged to review the connection between food pollen and undergo appropriate assessments for food allergy, intolerance and sensitivity. Food sensitivity includes sensitivity to gluten and sensitivity to cow’s milk (casein) proteins. Food intolerance includes lactose intolerance. Food allergies are separate and distinct from food sensitivity or food intolerance.

Consider taking genetic tests or asking your doctor to test you

This new information on the link between white blood cell protein models, the types of HLA DQ, suggests that we should consider doing genetic testing. After proper evaluation,

Establish a basic symptom score and start a dietary diary of food symptoms

I encourage everyone to establish a basic symptom score. A detailed diary of food symptoms before a trial of the elimination diet is also extremely helpful. We recommend an elimination diet that excludes the main food lectins (dairy products, cereals, legumes and eye shadows) and all foods from the list of pollens that you are allergic to before accepting diagnosis of IBS, fibromyalgia, unexplained neuropathy or headache and chronic fatigue syndrome. Any symptoms not easily explained or improved with other diagnoses and treatments should probably be considered due to a food reaction until proven otherwise.

Selected bibliography

Boehncke, et al. Clin Exp Allergy. 1998 April; 28 (4): 434-41.

End KD et al. Am J Gastroenterol. 2000 Aug; 95 (8): 1974-82.

Wang et al. Otolaryngol Head Neck Surg Feb; 130 (2): 192-197.

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