While sometimes complicated, allergies are the best understood of all unwanted food reactions because they always involve immune system reactions to very specific components in foods. If you have an allergic response to a food, certain proteins in your immune system identify and bind together with very specific components (called antigens) in foods. While food antigens are typically protein-like in nature, our immune system can mount an allergic response to some carbohydrates in foods, as well as some fat-plus-carbohydrate-containing molecules (called lipopolysaccharides). Still, in every one of these situations, our immune system gets involved in a food allergy, and, because it does, levels of immunoglobulins in our blood can be measured to document the allergenic response. (However, even though blood work can be used to help identify a food allergy, this blood work is not always conclusive, since food allergy tests can often show "false positive" results in which a food allergy is not actually present, and the immune system has reacted to some other non-food molecule.)

When should you consider the possibility that a whole, natural food that you enjoy is actually a bad fit in your meal plan due to food allergy? At WHFoods, we believe that it makes sense for everyone to consider the possible presence of a food allergy if they routinely eat foods commonly associated with food allergy. In the U.S., eight foods account for about 90% of all reported food allergies, and the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) requires that the presence of these foods—or any food ingredient containing a protein derived from one of them—be identified on food packaging labels. These eight most commonly allergenic foods are as follows.

To be sure, these eight foods are not the only foods that can trigger food allergy. However, they can be a good place to start in assessing food allergy risk. If you consume any of these foods on a regular basis, it's worth paying attention to see if you notice any pattern in the way you feel in the minutes and hours following food consumption. Most food allergies are both predictable and consistent in their occurrence. You typically don't experience an allergic reaction to the food on one day, and then no reaction whatsoever on the next. In addition, the timing and nature of the reaction are usually predictable. For example, if you feel cramps and pain in your abdomen two hours after eating a food, you would expect to experience the same problems in the same time frame whenever that food was eaten.

Given the very large number of factors that can cause symptoms resembling food allergy symptoms, it can be difficult to recognize this kind of pattern and link it up with food allergy on your own. Even if you are able to recognize a pattern on your own, food allergy many not end up being the culprit. That's because the same immune system proteins that can recognize and react to food antigens can recognize and react to molecules in bacteria, parasites, and pollens. It's possible to have an allergic reaction to any of these agents, and confuse the reaction with a food allergy. So as you can see, identifying a genuine food allergy can be complicated. However, it can be a step well worth taking for optimal nourishment and feeling your best. Many people find that reduction or elimination of verified allergenic foods from their meal plan results in very noticeable changes in their everyday sense of well-being. Often, the help of a healthcare provider is needed to identify a food allergy with certainty.

For persons interested in the more technical side of food allergy, we've created the following list of allergen types frequently found in animal and plant foods.

These are some common allergens found in animal foods:

These are some common allergens found in plant foods:

We'd like to complete this first section on food allergies by providing you with an example of an allergen type that is not as common as the allergens listed above but which can still be the source of an adverse reaction. This allergen type involves sesame seeds. On a global basis, and especially in countries like Canada, Japan, and Israel, researchers have documented an increased prevalence of sesame seed allergy. Studies have identified three factors as potentially contributing to the rise in sesame seed reactions. First has been an increasingly widespread use of sesame oil and sesame seed components in both food and cosmetic products. Sesame oil has become an increasingly common component in skin and massage oils and can also be found in hair care products, cosmetics, perfumes, soaps, topical oils, and sunscreens. Within the food supply, sesame oil can often be found in cookies, crackers, pastries, dips and spreads, soy burgers, tempeh, granola bars, and other foods. Tahini is a butter made from sesame seed. Gomasio is a sesame-based salt. Halvah is a sweet dessert often made using sesame paste. On a product label, you should suspect the presence of sesame whenever you see any of the following descriptions: sesamol, sesamolina, tahini, tahina, gingelly oil, til oil, or benniseed.

A second factor involves cross-reactivity with other foods. Although we address environmental cross-reactivity below in section 3 of this overview article, most of the research on sesame seed reactions appears to involve cross-reactivity with other specific foods rather than non-food cross reactions that would fall into the category of "environmental" (like cross-reactions to pollens from trees or grasses). While not fully conclusive, research in this area suggests that individuals with food allergy to peanuts, walnuts, hazelnuts, or cashews may also experience allergic response to sesame seeds. This allergic response is likely to involve proteins like Ses i 6 or Ses i 7 that are found not only in sesame seeds but also in the other foods listed above. Alternatively, the allergic response to sesame seeds may be related to proteins like oleosins (which are storage proteins found in a wider variety of nuts and seeds).

The intermingling of sesame seeds with other nuts or seeds during processing is a third factor that has added confusion to analysis of sesame seeds as a potentially allergenic food. Foods not expected to contain any sesame seed components have sometimes ended up containing sesame seed components through shared equipment at food processing facilities or through accidental contact during storage and transit (for example, rotation of nut and seed products in bulk storage bins). This intermingling of sesame seed parts with parts of other nuts and seeds may have increased our exposure to isolated sesame seed components in a way that is still somewhat confusing from a research standpoint and will take more time to evaluate. Adverse reactions to sesame seeds provide a good example of food allergies and their challenges from a research perspective.


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