Beware of elimination diet instructions (Part 2) – Which foods cause intolerances?

Let’s talk some more about whether it’s a good idea to try an elimination diet on your own to check for sensitivities to milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat and soybean. As I explained in an earlier post, these foods are known as the Big 8 food allergens in the US, and anyone who suspects that they have ever had an allergic reaction to one of these foods should talk with their doctor. As we saw, food allergies often diminish over time, but they will never cross over into a food sensitivity or intolerance.

With that established, we can move on to another issue: Can the Big 8 allergenic foods also cause intolerances? Well, it is true that wheat, milk, soy, and eggs can trigger flare-ups in people with irritable bowel syndrome (IBS), but to date, no one has established that this is related to allergy or to pharmacological food intolerance. We also know that lactose intolerance is real, and egg whites, soy sauce, and spoiling fish have the potential to cause adverse reactions by way of biogenic amines (including histamine). But, for the most part, the answer to my question is “No.”

This is not to say that people cannot have other problems with these foods. In fact, outside food allergies and the limited examples of food intolerance I just mentioned, doctors have identified several disorders in adults where the immune system unnecessarily reacts to certain food proteins – these are listed in the table below under ‘Other immune system reactions.’ These problems can be quite serious, so they are not something you should try to diagnose on your own.

Table 1. Possible reactions to the Big 8 food allergens in adults. When dealing with these foods, there are a lot of reasons to see a doctor and not many reasons to do an elimination diet on your own.
Foods Allergic reactions Other immune system reactions Food intolerances
Milk Cow’s milk protein allergy Cow’s milk protein intolerance
(unknown mechanism)
Lactose intolerance
Wheat Wheat allergy
Wheat-Dependent Exercise-Induced Anaphylaxis
Celiac disease
Dermatitis herpetiformis
Gluten sensitivity (?)
Soy Soy allergy Soy protein intolerance
(only in children)
Possible aggravation in celiac disease (?)
Possible amine intolerance to soy sauce (?)
Eggs Egg allergy
(to whites, yolk, or both)
Egg white intolerance
Crustacean shellfish Shellfish allergy Food protein induced entercolitis syndrome – FPIES
(rare but serious)
Fish Fish allergy Scombroid poisoning
Peanuts Peanut allergy
Tree nuts Tree nut allergy
Any food protein
(varies by person)
Eosinophilic esophagitis
(usually males)

One more thing: In the table above, I have classified reactions to the Big 8 foods as food allergy, food intolerance, and other immune system reactions; however, you might also run into the term ‘food sensitivity’ on the Internet. It’s important to be clear about what this phrase implies. In many contexts, ‘food sensitivity’ can be used as a generic term to describe any type of adverse reaction to food. I’m often guilty of using it this way. However, when someone recommends that you try an elimination diet or take a blood test to see whether you have ‘food sensitivities’ to the Big 8 foods, they are probably referring to something very specific – and very incorrect – namely, the idea that you may have some kind of chronic, low-level allergic reaction to food that is undermining your health. These IgG-based ‘food sensitivities’ don’t actually exist and so are not listed in my table of possible reactions.

To summarize, most reactions to the Big 8 foods are serious problems that require proper medical care; light-weight allergic ‘food sensitivities’ do not exist, so there is no need to test for them on your own. Even in the case of gluten sensitivity, you need to be checked for possible celiac disease before you go gluten free. And you certainly shouldn’t try to test yourself for egg white or fish/histamine intolerance without having properly ruled out allergies to eggs or fish. If you do feel that you are experiencing symptoms related to food, the best thing to do (after seeing your doctor) is talk to a registered dietitian about other foods that can cause food intolerance.

Last updated March 29, 2015

© 2014 Anna (Laurie) Laforest. All rights reserved.
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