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  • Adriano dos Santos

What exactly is food sensitivity?

First things first: it’s important to know that there’s a difference between food allergies, intolerances and sensitivities. Let’s look at them below in a bit more detail-

Allergies are immune reactions, involving IgE antibodies. They can be innate (you’re born with them) or acquired (developed later in life), and they cause immediate and sometimes life-threatening reactions, such as anaphylaxis. It’s most common to be born with an allergy, but children often grow out of allergies as their immune systems evolve - although this is not always the case.

Sensitivities are also immune reactions, often tested for via IgG antibodies (although other antibodies can be used - just not IgE). They involve a similar chemical release to allergies, but the result is usually less severe or less noticeable.

Intolerances are different to both allergies and sensitivities, as they are not immune reactions. Often, they’re related to an enzyme deficit, such as lactose intolerance, where people lack adequate lactase enzymes required to digest lactose sugar from dairy products. They can also be caused by an excess of a compound, for example, histamine intolerance, where people experience symptoms with high levels of histamine, as their bodies can’t tolerate the excess.

But let’s return to food sensitivities, which are important to identify. They’re generally less noticeable than allergies and sometimes have delayed reactions, which means they can go undetected for years while the individual suffers persistent symptoms with no known cause. Food sensitivity testing has been used favourably in various conditions, including:

  • Migraines

  • IBS

  • Inflammatory Bowel Diseases e.g. ulcerative colitis

  • Histamine intolerance

  • Coeliac disease (that doesn’t respond to removing gluten from the diet)

What causes food sensitivities?

1) The gut microbiome

An imbalance in the gut bacteria, or an infection, can contribute to food sensitivities. Therefore, any factor that disrupts a healthy microbiome can be considered a potential cause.

2) Stress

Something we’re all familiar with, the stress in any form has a huge impact on our health. It changes the way our nervous system works, so we’re constantly in a stimulated state - this aggravates our immune system, and it may start to create antibodies to substances that previously would have been tolerated, creating sensitivities.

3) Poor diet

A diet high in refined carbohydrates, gluten and food additives can disrupt the gut microbiome, as can a diet low in fibre or phytonutrients, which can lead to an aggravated immune system, an agitated nervous system and overall heightened sensitivity. All these things can impact our immune reactivity.

4) Nutrient deficiencies

Vitamins A and D play a key role in maintaining oral tolerance, which in itself is a source of reactivity and sensitivity but is also vital in letting our immune system know about the safety of every food we eat.

5) Medications

Perhaps a surprising cause, most medications change our body’s natural pathways in some way. Some, such as PPIs (e.g. omeprazole) and the oral contraceptive pill, may alter the gut microbiome, which can affect food sensitivities, and some will interact with the immune system (e.g. steroids), which alters its reactivity as a whole and potentially creates food intolerances.

Nutrition and Lifestyle Tips

1) Stress reduction

Stress has a huge impact on our nervous system, which is intricately linked with the immune system. So if your lifestyle is hectic, or you’re not sleeping enough, it’s worth making time to rest - it should be as much of a priority as the rest of your day.

2) A nutrient-dense diet

Unsurprisingly, nutrition plays a key role in optimising the gut biome, which is an important focus for food sensitivities. Make sure you include anti-inflammatory fats, such as oily fish, avocados and nuts, as well as plenty of different coloured fruit and vegetables to ensure a high intake of polyphenols - these can help to support and rebalance the gut ecosystem. Eating the rainbow really is good for you!

Supplement Suggestions

It’s important to note that supplements have different purposes – some help to alleviate symptoms, whereas some support the underlying physiological needs.

The following supplements are suggested to consider in light of your relevant expertise and intimate understanding of your needs. It is not intended for them all to be taken, but rather just those that are selected by your nutritionist. They may be used in isolation or as part of a multi-supplement strategy, but at all times the consideration of their use should be tied to the specific needs of the individual.

1) Bio.Me Barrier (Bio.Me)

This supports the gut lining and the gut’s immune response, as well as the breakdown of lipopolysaccharides (which can contribute to food sensitivities).

2) Partially Hydrolysed Guar Gum - Healthy Fiber (Healthy Origins)

A prebiotic helps to regulate and rebalance the gut, which can support food sensitivities.

3) Digestive Enzymes Ultra (Pure Encapsulations)

If your food sensitivity is worsened by poor digestion, taking some digestive enzymes might help to alleviate some symptoms of sensitivity.

4) Vitamin D (Designs for Health)

Vitamin D is vital for immune system function and is especially important for those who live in countries which get less sun.

5) Vitamin A (Pure Encapsulations)

Vitamin A is essential for various functions of the body, including the immune system and the digestive system, and so can help with sensitivities.

6) Mega Mucosa (Microbiome Labs)

This supports the rebuilding of the gut lining and the restoration of gut immunity, in addition to boosting the immune system within the gut.

As always, it’s a simple example of a protocol. However, every individual can be slightly different. Please check with your practitioner before taking any supplements. And please do not stop taking any medication without speaking to your doctor first.


Geiselman (2019) The Clinical Use of IgG Food Sensitivity Testing with Migraine Headache Patients: a Literature Review, Curr Pain Headache Rep, 2019 Aug 27;23(11):79

Atkinson (2004) Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial, Gut, 2004 Oct;53(10):1459-64

Jian et al., (2018) Food Exclusion Based on IgG Antibodies Alleviates Symptoms in Ulcerative Colitis: A Prospective Study, Inflamm Bowel Dis, 2018 Aug 16;24(9):1918-1925

Wang et al., (2019) Serological investigation of IgG and IgE antibodies against food antigens in patients with inflammatory bowel disease, World J Clin Cases, 2019 Aug 26;7(16):2189-2203

Xiao N, Liu F, Zhou G, Sun M, Ai F, Liu Z. (2018) Food-specific IgGs Are Highly Increased in the Sera of Patients with Inflammatory Bowel Disease and Are Clinically Relevant to the Pathogenesis, Intern Med. 2018 Oct 1;57(19):2787-2798

Caminero (2019) Mechanisms by which gut microorganisms influence food sensitivities, Nat Rev Gastroenterol Hepatol;16(1):7-18

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