Food Sensitivities, Intolerances, and Allergies: What’s The Difference?

If you’re wandering down any typical grocery store, you will usually come across one isle or two promising “freedom” from some of the typical things most people eat: gluten-free, dairy-free, egg-free, soy-free, and the list goes on. You may have wondered if those foods are healthier, and if you should also be filling your grocery cart in that isle.

Food sensitivities and allergies are on the rise in North America. It’s hard to plan a kids’ party without someone having some dietary restrictions.  So, what’s the difference between food sensitivities, intolerances, and allergies?

Food Allergies

Most people with food allergies found out the hard way. They ate some peanuts and had difficulty breathing, or ate some strawberries and broke out in hives. These reactions are usually severe, and are mediated by a type of antibody called IgE (antibodies are produced in the body and attach to specific protein sequences that they recognize). If you went to an allergist and got pricks in your forearms, you were most likely tested for IgE reactions.

Symptoms of food allergies usually show up fast, usually starting within 15min of consuming the food, and can be quite severe. They are the type of food reaction that is usually immediate, and are associated with anaphylaxis. If you have a food allergy, you have to be very careful about avoiding even trace amounts of the food in question.

Food Sensitivities

Food sensitivities are typically harder to pinpoint than food allergies, so many people go undiagnosed for years. They are delayed reactions to food mediated by a different type of antibody, IgG. Symptoms occur most commonly within the first day of eating a food, but can occur up to 3 days after. The symptoms of a food sensitivity tend to be more subtle than a food allergy. They can include:

-digestive issues (bloating, gas, diarrhea, constipation, etc.)
-foggy thinking
-feeling like food “just sits there” and doesn’t digest well
-migraine headaches
-fatigue
-difficulty losing weight
-skin issues (acne, eczema, psoriasis)
-behavioural issues in children

Food sensitivities can be identified either through an elimination diet, or through IgG food sensitivity testing. Many patients opt for IgG food sensitivity testing to get a more objective starting point of which foods to start eliminating. This involves a simple blood test that will look at the level of IgG produced with respect to 120-200 foods. However, food sensitivity testing is still controversial. It is not 100% accurate, must be interpreted in the light of what is going on with the patient, and possible cross-reactions (i.e. shellfish IgG can show up high in someone with a dust allergy because the body recognizes a similarity between them). False positives can occur if the patient has a condition referred to as leaky gut syndrome (where the bowels are hyper-permeable and allow too many undigested foods through). False negatives can occur if you have not been eating a certain food, so it is better to do the testing before you start eliminating foods from your diet.  

In research studies, IgG-based elimination diets have been found to help with:

-both migraines and irritable bowel (Aydinlar et al., 2013)
-IBS (Drisko et al., 2006; Atkinson et al., 2004)
-Crohn’s disease (Bentz et al., 2010)

Despite the lack of conclusive research, I have found the test to be very clinically relevant in practice: most of my patients with the relevant symptoms improve quite dramatically when we remove their food sensitivities from their diet.

Food Intolerances

Reading through articles can be confusing, since the term “food sensitivities” and “food intolerances” is often used interchangeably. However, food intolerances are non immune-mediated reactions to food (no antibodies are involved). Typically, the body will lack something which will make it intolerant to a food. A common food intolerance is lactose intolerance, where one cannot tolerate lactose-containing dairy products because he/she lacks the lactase enzyme in the digestive tract necessary to break down lactose. With lactose intolerance, symptoms usually occur within 30min of consuming lactose, leading to stomach cramps, abdominal pain, and diarrhea.

An elimination diet can help identify both food sensitivities and food intolerances. It may take some further testing after that to identify if, for example, your reaction to dairy is due to a sensitivity or an intolerance.

What To Do About Them

Once you identify which foods are a problem for you, there are healthy and not-so-healthy ways to eliminate them from your diet. Many of the specialty foods free of common allergens/sensitivities are highly processed, and contain fillers, emulsifiers, and sugars to make the texture or flavour more similar to their regular counterparts. Your best bet is to stick with whole foods that are minimally processed most of the time, and only have the processed ones as an exceptional treat. You may also need additional supplements to help heal your gut barrier so that you can potentially tolerate your sensitivities more in the future.

Do you think you may have a reaction to a food you are consuming? If you have any questions or would like to get started on an elimination diet or IgG food sensitivity testing, please contact us and we'll help you out!

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References

Atkinson W1, Sheldon TA, Shaath N, Whorwell PJ.Gut. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut. 2004 Oct;53(10):1459-64.

Aydinlar EI1, Dikmen PY, Tiftikci A, Saruc M, Aksu M, Gunsoy HG, Tozun N. IgG-based elimination diet in migraine plus irritable bowel syndrome. Headache. 2013 Mar;53(3):514-25.
 
Bentz S1, Hausmann M, Piberger H, Kellermeier S, Paul S, Held L, Falk W, Obermeier F, Fried M, Schölmerich J, Rogler G Clinical relevance of IgG antibodies against food antigens in Crohn's disease: a double-blind cross-over diet intervention study. Digestion. 2010;81(4):252-64.

Drisko J1, Bischoff B, Hall M, McCallum R. Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. J Am Coll Nutr. 2006 Dec;25(6):514-22.

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