True food allergies occur when the body develops specific responses against certain foods. People can have different reactions to food, including sensitivities, allergies, or other types of responses. Sometimes, individuals may be surprised by a food antigen test result showing a reaction to a food they don't typically consume.
How can that happen? Since a food allergy involves the development of specific responses, how would these responses develop if the food isn't consumed? There are several possible explanations.
This article will explore food allergies and sensitivities, how the body responds to them, and what food and/or environmental exposures can activate these responses.
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Ruling Out Labeled Allergens
When someone reacts to food, it's important to first check if a hidden allergen is present in their diet.
Sometimes, people consume foods without realizing it. For example, ingredients in packaged foods like stabilizers, emulsifiers, thickening agents, and preservatives might be overlooked. Examples include cornstarch, carrageenan (from algae/moss), tapioca, arrowroot, guar gum, and gelatin.
There are also ingredients that people might not realize are common in some foods, such as gluten from wheat in soy sauce, anchovy in Worcestershire sauce, and certain food colorings. It's helpful to discuss with individuals about sauces and flavorings they use and encourage them to read labels carefully to rule out any unknown allergens.
Ruling Out Hidden Allergens
Another possibility is that someone might be consuming hidden allergens. These are different from labeled allergens because they might not be obvious from a label, making them easier to miss. Eating out can be particularly challenging when trying to identify which allergens are present. Some restaurants provide detailed allergen information, while others may not be as informed or may not communicate the information effectively. Even restaurants that note specific allergens can make mistakes, such as not having separate cooking areas for different foods, leading to cross-contact.
Outside of restaurants, packaged foods might be processed on equipment that also handles allergens. Certain hidden additives might not be required to be listed on a label if used in small amounts under US or EEC guidelines.
Common "hidden" allergens include mustard, celery, spices, lupine, pea, natural food colorings, and preservatives, but can occasionally include allergenic material from contaminants such as cereal mites." (1)
Ruling Out Cross-Reactivity Between Foods In The Same Family
Another possibility is cross-reactivity between foods in the same family. Foods are grouped into families because they are related and can sometimes cause similar responses. Although it might be confusing if a test shows a reaction to a food not usually consumed, it can provide an opportunity for more effective management. After a positive food antigen test result, it is common to follow an elimination diet, where reactive foods are removed and gradually reintroduced.
Foods in the same family that can be cross-reactive are also recommended to be eliminated to allow for a complete chance for improvement. It's beneficial to consider a broader range of foods, as long as the approach is based on comprehensive testing that provides guidelines for elimination based on various markers.
Gluten or Wheat Allergy
A gluten or wheat allergy is an important result that can be identified. It's common for both gluten and wheat to show up together as positive if either does. Sometimes, a person may test positive for gluten but not wheat or vice versa. Wheat contains gluten, but gluten is also found in many other grains. If gluten shows up but wheat doesn't, the person may not have consumed wheat, so the cross-reactivity isn't as strong. If wheat shows up, but gluten doesn't, then it's more likely that the person is reacting to other compounds in the wheat.
Mold Allergy
Mold positivity could be related to foods like cheeses that contain mold, peanuts, melons, sake, vinegar, kombucha, alcohol, soured breads, fermented foods, cider, rootbeer, pickled and smoked meats, dried fruits, canned tomatoes, and canned juices.
Why? Sometimes because the mold has contaminated the food (dried fruit and tomatoes rarely are completely mold-free), and sometimes because specialized molds are used on purpose to ferment the foods (like kombucha, sake, and soured foods).
Yeast positivity can be possible because a person is experiencing an overgrowth of Candida. Consider how related foods can cross-trigger as well. Examples include almonds with peaches, asparagus with garlic or onions, avocados with cinnamon, cacao with kola nut, spinach with quinoa, etc.
Other Reasons For Reactions
Sometimes, a specific food won't appear on the test as an allergen or sensitivity when a person knows they are reactive. There are several possible reasons for this as well. Foods high in histamines (like smoked meats, cheeses, etc.) can cause a direct reaction to the histamines in the food rather than an allergic reaction to the food itself. Likewise, foods like smoked meats can be high in nitrates and nitrites. Wine can be high in sulfites, etc.
These chemical reactions are not allergic reactions to the foods themselves, and when an allergy doesn't show up, it can lead the person to continue consuming meats and wines, for example.
There can be non-allergic reactions to gluten because gluten may interfere with the ability to convert amino acids into neurotransmitters. Specific foods might cause a platelet-activating factor- not an allergy, but a noticeable reaction. Depending on the person, other foods may be high FODMAP. The P88 Dietary Antigen Test is a helpful tool for identifying potential reactions, but like other valuable tools, sometimes it may just rule out a pathway.
Ruling Out Cross-Reactivity To An Environmental Allergen
Another possibility for why a food that a person doesn’t consume may still show up in the results of a food antigen test is because of cross-reactivity to an environmental (often airborne) allergen.
Some of these allergens are very interesting. For instance, someone who shows up as reactive to beef but is a vegetarian might be surprised. It turns out that beef reactions can cross-react with tick-related responses. In fact, someone who doesn't eat beef and tests positive for that food reaction should be examined for symptoms related to tick exposure.
People who don't eat seafood but test positive for clams may cross-react with a response to roaches.
Latex can cross-react with bananas and a variety of other foods. Meat reactions can be cross-reactive to animal dander. Many pollens can cross-react with fruits and vegetables.
Maple syrup and barrel-aged products (including alcohol) may cross-react with the pollen from the trees used to age them (an ongoing area of research that is sometimes debated by the wine and spirits industry). It's wise to consider the environmental interplay when a specific food is tested as positive for a person who says they don't consume that food.
The Physician's Guide to the P88 Food Antigen Test contains a chart showing potential environmental and food interactions.
Testing for Food Allergens and Cross-Reactivity
The Precision Point Diagnostics P88 Dietary Antigen Test evaluates various foods for IgE, IgG, IgG4, and C3d responses. The 88 foods on the test were chosen to represent a spectrum of foods common in the diet to have the most comprehensive usefulness to the clinician. In addition, the range of foods on the panel can be an excellent tool for identifying some foods that do not appear. Various food groups can show cross-reactivity with each other, allowing the clinician to consider foods outside the panel's scope.
This allows the physician to decide which food groups should be focused on for entire elimination (particularly those associated with a high C3d result indicating systemic responses and a low IgG4 reaction meaning little alleviation of responses through that response) and which food groups can be ignored altogether or only partially decreased in the elimination diet.
As individual foods are reintroduced, the family cross-reactivity is zeroed in for that person.
Precision Point Diagnostics also offers a free physician's guide to the P88 Dietary Antigen Test that not only describes the test in full and how to interpret it but also contains comprehensive tables on foods that are cross-reactive classified in groups, as well as a table on the interaction between specific environmental factors and which foods they can interact with.
Although you'll find a complete list of cross-reactive foods in the Physician's Guide tables, let's look at some of the interactions that might be of particular interest.
Summary
Food antigen testing is a complex process because of the various pathways through which food responses are formed. Understanding the interplay of foods with each other, foods with the environment, hidden food allergens, and the types of responses can help healthcare providers better support their patients. Food responses are as diverse as the individual, and this is why simple food tests that don't consider the interactions between different pathways for responses don’t tell the whole story. Elimination diets can be challenging for individuals to follow. The more clearly you can explain the reasons to them, the greater the degree of success you are likely to have.
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