Food Allergies, Sensitivities and Intolerances

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Food Allergies, Sensitivities and Intolerances

More than 20% of the population in industrialized countries suffers from food intolerance or food allergy (1).

The terms allergy, sensitivity and intolerance to certain foods are used frequently. 

What is the difference between these different types of reactions? More importantly, what can you do to manage symptoms, or better yet, resolve the problem?

Food allergies are increasing:

  • Approximately 1 in 13 children and 1 in 25 adults in the US suffer from a life-threatening foosibod allergy (2)
  • From 1997 to 2011 there was a 50% increase in food allergies in American children (3)
  • In the United States, food allergies affect 8% of children (4)
  • A study done in 2013 found that the overall economic cost of food allergy was estimated at $24.8 billion annually ($4184 p.a. per child) (2)

Food Allergies

A food allergy is when the immune system believes a particular food to be pathogenic or dangerous and creates an IgE (immunoglobulin E) antibody to that food. The antibody will bind to that food (the irritant or antigen) which signals to the immune system that this ‘dangerous’ substance must be removed. Immune cells called macrophages then destroy the substance. During this process, histamine and other chemicals are created which can cause an allergic reaction.

Symptoms vary and can include: digestive problems, tingling or itchy mouth, hives, itching, eczema, swollen airways and difficulty breathing. Severe reactions can be life-threatening.  Symptoms can appear immediately or take a few hours to appear.

Common food allergens are: eggs, dairy products, nuts, soy, wheat/gluten, and shellfish. People can have allergies to other foods not on this list.

Food Intolerances or Sensitivities

A food intolerance is thought to be caused by a specific gut issue like an enzyme deficiency (i.e. lactase to digest lactose found in dairy products), difficulty processing a certain chemical (i.e. caffeine), poor absorption or other issue that impairs proper digestion of the particular food (1). With a food intolerance, antibodies are created in an IgG (immunoglobulin G) or IgA (immunoglobulin A) reaction. These reactions are thought to be more related to gut permeability (i.e. leaky gut) than to a true allergy (5). Food intolerances are thought to be more common than food allergies and can occur with any food, food additive or preservative.

Symptoms vary and can include: rashes, skin issues, asthma, GI symptoms like cramps, constipation, diarrhea and neurological symptoms such as migraines. Symptoms can take hours or days to appear which makes identifying the issue a challenge.  They are typically not life-threatening. They can be addressed, though, and addressing them can reduce inflammation in the gut and improve overall gut health.

A food sensitivity is another term for a food intolerance.

Gut Health

As you may have picked up from our previous blog articles, many conditions link back to the health of the gut. This is the case with food allergies and even more so, with food intolerances.

Both allergies and intolerances create inflammation. With a food allergy, it can push the immune system into overdrive or overreaction to a certain food which creates inflammation. A food intolerance creates inflammation in the gut.

As we mentioned in the last blog post on seasonal allergies, 70-80% of the immune cells is located in the gut so we need a well-functioning gut for optimal health. There is a risk with both food allergies and intolerances to potentially develop an autoimmune (AI) condition in the future, if they are not adequately addressed.

So What Can You Do?

Unfortunately a food allergy is usually an allergy for life so strict avoidance of the allergenic food is necessary to avoid symptoms, particularly if the allergy is severe. There are, however, things you can do to support your immune system and gut health which may help to mitigate symptoms. A food intolerance can potentially be reversed with diet changes and gut healing.

Work on Your GUT: Work to eradicate any GI infections or overgrowths that you might have. Work with a qualified functional medicine practitioner to test for these. This would involve a stool test like a GI-MAP or CDSA with Parasitology to check for dysbiosis, parasites, yeast, etc. and a 3-hour lactulose breath test to check for Small Intestine Bacterial Overgrowth or SIBO (For information about SIBO, read this article). Once you and your practitioner have eradicated any issues identified in testing, then follow a good gut healing program implementing some of the tips we recommend below:


  • Eat a whole foods-based, non-inflammatory diet. Focus on organic whole foods like vegetables, fruits and organic animal products.
  • Legumes, nuts, and seeds are fine if tolerated.
  • Cruciferous vegetables have compounds that can be specifically helpful for T-Regulatory cells in the immune system. Eating 3-5 cups (measured before cooking) of cruciferous veggies daily can be helpful. When having cooked crucifers like broccoli, it is helpful to have a small amount of raw crucifer like daikon radish, mustard, or arugula for some myrosinase enzyme that can help produce sulforafane, a helpful compound that can improve detoxification and reduce oxidative stress.
  • Some full-fat grass-fed dairy can be healthy if tolerated. However, if you do not know if you might have a sensitivity to dairy, it might be helpful to remove dairy for 30 days and then re-introduce it with one normal portion per day for 3 days. Some people react to lactose (a sugar in dairy that gets reduced in the fermentation process so fermented dairy has less than non-fermented dairy). Others react to casein (a protein in dairy).
  • Be sure to eat fermented foods like sauerkraut, kimchi, kefir, miso, and yogurt. Fermented foods contain live probiotics. Also eat prebiotic foods which feed the good gut bacteria and strengthen gut health. Prebiotic foods are lentils, potatoes that have been cooked then cooled at least 24 hours (eaten cool or at room temp but not re-heated), green plantains, onions, garlic, leeks, apples, green banana, asparagus.
  • Bone broth contains glycine, gelatin and glutamine which are all very healing to the gut lining.
  • Avoid as much as possible: alcohol, processed / junk / fast foods, GMO’s and excessive refined sugars as these are all damaging to gut health.
  • Reduce sugars and grains in your diet as these are inflammatory and can lead to poor gut health.
  • Reduce inflammatory omega 6 fats (vegetable oils) and increase anti-inflammatory omega 3 fats (fatty fish like wild salmon, sardines, anchovies, mackerel) to reduce gut inflammation.


  • Vitamin D is important for immune system health. Studies have shown beneficial effects of vitamin D on immune function, particularly in the context of autoimmunity (6). You can test your vitamin D levels with a functional medicine practitioner. An optimal level is in the 35-60 range. Parathyroid hormone (PTH) between 15-30 is a further sign that vitamin D is sufficient. If PTH is >30, typically either Vitamin D or Calcium is sub-optimal.
  • Vitamin A is important for T-Regulatory cell function / production. T-reg cells have Vitamin A and D receptors on them (see the seasonal allergies article for more details). Taking cod liver oil (1 tsp per day) or eating about 4-6 oz liver per week can provide a good dose of pre-formed Vitamin A.
  • Probiotics help to populate the gut with good beneficial bacteria. It can be helpful to take a daily probiotic supplement in addition to adding fermented foods to your diet. There are three classes of probiotics that can be helpful. One class often contains various lactobacillus and bifidobacterium. Another class is actually a healthful yeast called saccharomyces boulardii. The third class are soil-based or spore-based organisms usually containing bacillus species like bacillus subtilis and/or bacillus coagulans. Try each of these three probiotics, one at a time for 2 weeks to see if you notice benefit. If you do notice benefit, keep that one in and go to the next one. You can take one, two, or all three groups at the same time if beneficial.
  • Stomach acid is necessary to break down foods and for good digestion. In experiments done over 70 years ago, the effects of stomach acidity on food allergen uptake were studied. It was found that increased stomach acidity and the presence of other food in the gut decreased absorption of the offending allergenic food, while decreased stomach acidity, such as from H2-blockers and proton pump inhibitors, and ingestion of alcohol, increased absorption of the allergenic food (7). Ensuring that your stomach acid is sufficient will help then with both food intolerances and food allergies. You can take HCL betaine and bitter herbs. It is best to work with an experienced practitioner in determining the right levels of HCL for you. Do not use HCL if you have an ulcer.
  • Digestive enzymes can help break down proteins, carbs, and fats. Breaking proteins down helps reduce the immune system trigger from a food because the more undigested the protein, the more potential it has to trigger the immune system. The more broken down the protein is, towards the amino-acid building blocks of the protein, the less likely it is to trigger the immune system. Taking digestive enzymes with every meal may help in cases of food sensitivities.
  • Quercetin has anti-allergic properties that stimulate the immune system, inhibit histamine release and reduce inflammatory immune cells. Based on a study in rats with peanut allergies, quercetin was found to reduce the histamine reaction and to suppress the IgE responses against peanut proteins (8). The study concluded that quercetin can be used to defend against IgE-mediated food allergies (8).
  • Glutathione is a powerful antioxidant and can also help support t-cells. Taking 200-1000 mg per day may be helpful.

If you suffer from known food allergies or intolerances, or simply have undiagnosed symptoms, then get in touch with us today. We can help to identify your food allergies or intolerances and more importantly, help you to get to the root causes and work towards minimizing symptoms.Book a discovery call today where someone from our staff can answer your questions and help you book an initial consult with one of the functional medicine doctors in our clinic.


  1. Zopf Y, Hahn EG, , Raithel M, Baenkler H-W, Silbermann A. 2009. The Differential Diagnosis of Food Intolerance. Dtsch Arztebl Int. 2009 May; 106(21): 359–370. doi: 3238/arztebl.2009.0359.
  2. Gupta R, Holdford D,Bilaver L et al. 2013. The Economic Impact of Childhood Food Allergy in the United States. JAMA Pediatr. 2013;167(11):1026-1031. doi:10.1001/jamapediatrics.2013.2376.
  3. Jackson KD, Howie LD, Akinbami LJ. 2013. Trends in allergic conditions among children: United States, 1997-2011. NCHS Data Brief.2013 May;(121):1-8.
  4. Gupta RS, Springston EE, Warrier MR,  et al.  The prevalence, severity, and distribution of childhood food allergy in the United States [published online June 20, 2011].  Pediatrics. doi:10.1542/peds.2011-0204.
  5. Shakoor Z, AlFaifi A, AlAmro B, AlTawil LN, AlOhaly RY. 2016. Prevalence of IgG-mediated food intolerance among patients with allergic symptoms. Ann Saudi Med. 2016 Nov-Dec;36(6):386-390.
  6. Prietl B, Treiber G, PieberTR, Amrein K. 2013. Vitamin D and Immune Function. Nutrients 2013, 5(7), 2502-2521;
  7. Sampson HA. 2016. Food allergy: past, present and future. Allerg. Intl. October 2016Volume 65, Issue 4, Pages 363–369. DOI:
  8. Mlcek J, Jurikova T, Skrovankova S, Sochor J. 2016. Quercetin and Its Anti-Allergic Immune Response. Molecules. 2016 May; 21(5): 623. doi: 3390/molecules21050623.

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