Monday, July 09, 2007
Genetics of Food Allergy and Food Sensitivity
Can genetics explain if you are allergic to some pollens or foods? White blood cell patterns determined genetically and designated as HLA DQ and DR genes have been identified with an increased risk of pollen, dust, latex, and food allergies. The intriguing part of this story is that there is an advantage to knowing your HLA DR and DQ type when evaluating your risk for pollen allergies and their associated food allergies or cross reactions.
We all have proteins on the surface of our cells that are genetically determined. These patterns are easily detectable by testing cells from blood or from the mouth. Specific patterns have been associated with increased risk for autoimmune conditions, gluten sensitivity and celiac disease. Now it appears certain DQ or DR patterns are associated with food and pollen allergies as well.
Boehncke, et al. from the University of Frankfurt reported in 1998 that certain white blood cell types known HLA class II genotypes or HLA DQ and DR genetic patterns were found more frequently in people with certain pollen associated food allergies. HLA-DQB1*0301 is present in more people with grass pollen allergy. Those with HLA-DRB1*08, an inherited white blood cell protein pattern linked with a grass pollen allergy, have six times the increased risk of peanut allergy.
Those who have inherited the HLA-DRB1*12 white blood cell pattern are 13 times higher at risk for carrot allergy. Birch pollen associated hazel nut allergy is linked to HLA-DRB1*01, DQA1*0101, and DQB1*0501. Hazel nut, almond, walnut and apple are the most common food allergies associated with birch tree pollen. Allergies to those foods are commonly associated with birch tree pollen in other studies. To download a printable table that lists the common foods that cross-react with various pollens, dust, and latex allergens go to the Food Doc resource page.
In 2004, Wang et al. from China published that the inherited white blood cell type DQA1*0302 is found in more people with Artemisia pollen-induced allergic rhinitis. This is hay fever due to the weed Mugwort also known as Sagebrush. Mugwort allergy is associated with several oral allergy food reactions including those from apple, celery, hazelnut, pistachio, lettuce, almond, peanut, and carrots.
The OAS literature contains numerous reports of food allergy or intolerance reactions associated with specific pollen, dust, mold or latex allergies. One of the best examples is ragweed pollen allergy. It is associated with a higher risk of food allergy or intolerance to only a few foods. These include foods in the gourd family (cucumbers and melons) and bananas. On other the hand, Birch tree pollen allergy is associated with sensitivity to many foods. The list includes those foods in the Rosacea family (apples, pears), tree nut family (hazelnut, almond, walnut), potatoes, and carrots. Reactions include classic allergic reactions such as skin rashes (atopic dermatitis, hives), wheezing (asthma), runny nose (allergic rhinitis), as well as the burning mouth OAS symptoms and other food intolerance symptoms.
It is helpful to establish a baseline symptom score. This can be done on-line or by printable symptom survey form at the Food Doc resource page. A detailed food symptom diary before a trial of elimination diet is also extremely helpful. An elimination diet before accepting diagnoses of IBS, fibromyalgia, unexplained neuropathy or headaches, and chronic fatigue syndrome is recommended. Any symptoms not readily explained or improved with other diagnoses and treatment should be considered to be possibly due to a food reaction until proven otherwise. This new information about the link of white blood cell protein patterns, HLA DQ types, suggests that we should consider having genetic testing done as well. Learn more at www.thefooddoc.com.
Boehncke, et al. Clin Exp Allergy. 1998 Apr;28 (4):434-41.
Fine 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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