Along with avoiding the eight most common food allergens, be aware of the cross-reactions that can be triggered by foods that are of similar origins. For example, if you develop an allergy to latex, you could also be sensitive to fruits of similar types of trees, which might include bananas, nectarines, avocados and other trees with sap that has rubber-like properties. The type of allergy at work here is called Oral Allergy Syndrome, and occurs when pollen of one allergen sensitizes you to fruits, vegetables and occasionally nuts from the same family of plant. If you have pollen allergies, you will want to watch for these cross-reactions:
- Ragweed allergy theoretically cross-reacts with bananas and melons, so people with a ragweed allergy might also react to cantaloupe, honeydew or watermelon. Also suspect are tomatoes, Echinacea, zucchini, sunflower seeds, dandelions and chamomile tea.
- Birch pollen allergy sufferers may react to apples, pears, peaches, kiwi, plums, coriander, fennel, parsley, celery, cherries, carrots, hazelnuts, and almonds.
- According to the AAAAI, people with grass allergy may react to peaches, celery, tomatoes, melons, and oranges, according to the AAAAI.
- Mugwort allergies are associated with sensitivity to celery, carrot, spices, melon, apple, hazelnut and chestnut
OAS tends to develop over time with repeated exposure to the primary allergen as well as to the trigger food. Because the reaction can be rapid, coming within half an hour of eating the offending food, and severe (including facial numbness, swelling of the throat and nasal passages leading to airway obstruction and anaphylactic shock), do not eat a food if it has previously given you even minor reactions such as tingling of the tongue, itching or numbness of the lips, tongue or face or swelling of nasal passages or glands in the throat. If it is a favorite food, under close supervision try it cooked, peeled or canned. The proteins that are most reactive are found in the skins of fruits and vegetables, so peeling may eliminate enough of them to allow you to tolerate the food. Cooking, including the heating process used in canning, breaks down those proteins and potentially renders them harmless.
Other types of food allergy or intolerance require you to avoid different foods. If you are allergic to wheat, it is instructive to determine whether it is actually the gluten to which you are sensitive. True celiac disease, in which the patient lacks the enzyme to break down the gluten, is relatively rare. However, immunoglobulin-mediated responses to wheat do occur, and there is growing evidence that some people just feel better if they avoid it. If you suspect you are sensitive to wheat gluten, you will probably want to avoid any gluten-containing grain, including barley and rye in addition to all forms of wheat. Buckwheat is among the gluten-free grains and despite its name is not really wheat.
If you are allergic to any one type of shellfish, you have a 75% chance of being allergic to another or all of them, but there is usually little cross-reactivity to other fish. Avoidance of all types of shellfish is necessary if allergy is a concern, because shellfish allergy accounts for up to 1/3 of all serious allergic reactions. It is a common misconception stemming from the 1970s that shellfish allergy is actually allergy to iodine. There is no evidence that this is the case, nor is there any correlation between shellfish, iodine and radio contrast dyes (used for CT scans and other medical imaging), another common allergy.
Tree nuts (as opposed to peanuts, a legume) are a common allergen, and once again you would want to avoid all tree nuts after developing an allergy to one variety, at least until the extent of the allergic response has been determined. Peanuts are among the most common allergies of all, and despite advice found in research for the section above on childhood allergy, there is some evidence that delaying introduction of peanuts and peanut products to a child’s diet has little effect or even contributes to later development of the allergy. It is this type of confusing evidence that makes diagnosing allergies and determining what allergens are at work so difficult.
Most alternative practitioners will also tell you to avoid sugar, mucous-forming foods such as cow’s milk and other dairy, refined grains and other highly processed foods. Some will also warn against alcohol, chocolate, tea, coffee, meats and other animal protein, smoked, salted or pickled foods and any foods containing artificial flavorings or coloring. We agree that many of these foods are nutritionally void and some have been shown to be carcinogenic. However, we take exception to eliminating chocolate; one of the great pleasures in life that also has antioxidant properties…unless you are sensitive to it, of course.