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

    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
    (histamine)
    Crustacean shellfish Shellfish allergy Food protein induced entercolitis syndrome – FPIES
    (rare but serious)    		 –
    Fish Fish allergy – Scombroid poisoning
    (histamine)
    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.
    Photo © Can Stock Photo Inc.
    FoodConnections.org – Food intolerance resource with a scientific twist

    Anna L. Laforest

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  • Beware of elimination diet instructions (Part 1) – Don’t mess with the Big 8!

    Beware of elimination diet instructions (Part 1) – Don’t mess with the Big 8!

    I have mixed emotions whenever I see an article on the Internet that instructs people on using an elimination diet to discover their food sensitivities. Of course, it’s not the idea of an elimination diet that bothers me – I have said many times that a properly done elimination diet and food challenges are the only way to diagnose food intolerance. These articles worry me when they suggest testing for sensitivities to foods that are on the list of Big 8 allergens. Simply put, don’t mess with these foods without consulting your doctor.

    The Big 8 foods account for 90% of the food allergies in the US. (Interestingly, the most common food allergens vary by country.) The Big 8 foods are milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat and soybean. Other notable allergens include buckwheat, sesame, celery, mustard, and even corn. Fruits can also cause allergic reactions, and, quite frankly, it is possible to be allergic to any food, even if it isn’t commonly thought of as an allergen. Deadly anaphylactic reactions in adults are most often caused by peanuts, but any allergen can lead to a life-threatening reaction, even when your previous reactions were mild.

    Adult-onset allergies

    Did you know that it is possible for adults to develop food allergies after a lifetime of being able to eat anything? Allergies can start at any age, and adult-onset food allergies come with an increased risk for severe reactions.

    Recently, doctors from Northwestern University [1] wanted to learn more about adult-onset food allergies, so they looked at the medical records of 1,111 patients from their allergy clinics. Fifteen percent of these patients were newly diagnosed as adults. In this group, the average age of onset was 31 years old, and 64% of patients were women. Shellfish and fish were the most common allergens, but all of the major allergens were represented.

    If you think that you may have experienced an allergic reaction to a food in the past – even something as small as tingling in the mouth or a delayed reaction – ask your doctor for help in ruling out food allergies. For each person, the minimum amount of allergen required to produce a reaction is different. While the minimum amount for some foods is generally small (think peanuts), others often require larger amounts. When you ‘challenge’ yourself with a food to see whether you have a reaction, you don’t want to get into trouble by eating a large amount of something you wouldn’t normally eat. Even if your doctor allows you to do the food challenges on your own, it’s better to have asked than to be sorry later.

    You might wonder why certain Internet MDs and nutritionists are giving out bad advice on testing for sensitivities to these allergenic foods. Unfortunately, they are basing their advice on misinformation from the alternative medicine community. Alternative medicine will have you believe that there is a lower grade of allergic reaction – originally referred to as food intolerance but now most often called a ‘sensitivity’ – that occurs when your IgG antibodies try to protect you from harmful foods. (A different antibody, IgE, is responsible for true allergic reactions.) As the story goes, IgG-based symptoms are delayed but never deadly. The truth is, these reactions don’t exist, and IgG antibodies are present in all of us as a sign that we can tolerate the foods that we commonly eat, like wheat, milk, eggs, soy, etc. Don’t mistake your mild but true allergic reactions for one of these ‘sensitivities.’ Even though food allergies often diminish over time, they will never cross over into a food sensitivity.

    For more information on the common foods that produce allergic reactions (and for some interesting reading, too), check out these websites:

    Stay tuned for a second article on this topic, where I will discuss the other conditions associated with these food allergens that you should talk to your doctor about.

    Last updated September 25, 2015

    © 2014 Anna (Laurie) Laforest. All rights reserved.
    Photo © Can Stock Photo Inc.
    FoodConnections.org – The skeptic’s guide to food intolerance

    References

    1. Kamdar TA, Peterson S, Lau CH, Saltoun CA, Gupta RS, Bryce PJ. Prevalence and characteristics of adult-onset food allergy. The Journal of Allergy and Clinical Immunology: In Practice. 2015 Jan;3(1):114–115.e1.

    Anna L. Laforest

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