I think I have a food sensitivity? What are my options?

Do you wonder if your symptoms may be from a food sensitivity? Perhaps you have a strong feeling something you’re eating is affecting you, but you’re struggling to pinpoint exactly what?

Symptoms of a food sensitivity can vary greatly dependent on how they affect your body. Some common signs you may be eating something that’s not agreeing with you include:

  • Fatigue
  • Brain fog
  • Headaches and Migraines
  • Joint pain
  • Fluid retention
  • Bloating, wind and digestive upset
  • Diarrhea and/or constipation
  • Hayfever, sinus congestion or post nasal drip
  • Eczema and skin rashes
  • Irritable bowel syndrome
  • Poor immunity
  • Dark circles under your eyes


I can’t tell you how many times clients have been concerned their symptoms may be from a food sensitivity.  Food sensitivities and intolerances are different from food allergies and are notoriously tricky to pinpoint. Whilst at times effects of food sensitivities can be sudden, in many cases they are delayed (even up to 72 hours!). This means working out what set you off can be difficult.

Think about that a little more-  you could be eating something on Saturday and symptoms may not appear until Tuesday. I can promise you by the time Tuesday comes around you are unlikely to be considering what you ate on Saturday to be at fault. Perhaps you’re reacting to something your eating every day, so you really don’t ever feel any different, it’s just “normal” to you. It’s “normal” to feel lethargic, foggy, hayfevery, stiff or sore, a bit bloated and just blurgh. It’s the same every day so you think nothing of it.

Reactivity may also depend on amount of offending foods consumed and thresholds being reached rather than any exposure at all. It’s not necessarily the case that you will feel the same every time you eat a problematic food.

The bottom line is you need to listen to your body. If something doesn’t feel right, even if you can’t put your finger on it yet or tie it to any particular food, you need to listen to that wisdom and explore further.


Food sensitivities can be to common food proteins, despite them often being healthy foods.

Food Allergy is not the same as Food Intolerance or Food Sensitivity

Food allergies can be mild, moderate or severe, with the most serious of all allergies being Anaphylaxis, a potentially life threatening reaction. They trigger IgE immune reactions, and in the majority of cases are immediate, fast and have obvious symptoms. IgE is a potent initiator of histamine release which causes symptoms of hives, wheezing and anaphylactic reactions. Seasonal allergies (like hayfever) are also IgE reactions leading to a histamine-mediated response.


Food intolerances often refer to a wide range of adverse reactions to foods that usually involve the digestive system. These may at times be due to an enzyme deficiency.

This includes things like:

  • Metabolic conditions: lactose intolerance and carbohydrate malabsorption (fructose, sucrose, polyols).
  • Pharmacologic (chemical sensitivity) reactions to naturally occurring food chemicals: MSG, caffeine, sulpur, oxalates, salicylates and amines
  • issues with FODMAPS
  • Reactions to preservatives such as sulphites and benzoates (though these preservatives have also been reported as triggers for asthma and anaphylaxis).
  • Non-coeliac gluten sensitivity


Different again are food sensitivities as these trigger IgG immune reactions. These are typically referred to as delayed hypersensitivities. They are still immune mediated reactions, but are referred to as sensitivities, not allergies. Whilst these IgG reactions are not life threatening, they can cause symptoms and significant discomfort for some none the less.


What your likely to get tested from your GP or Immunologist

When it comes to testing from your GP or medical professional, the most likely tests they will perform will be IgE tests. These are the classically understood allergies we discussed earlier. These are done via measuring blood levels of IgE antibodies to specific foods or things in your environmental (dust, pollens, animal dander etc), or through skin prick (RAST) testing. Depending on your symptoms you might also be screened for coeliac disease, lactose, sucrose or fructose intolerance.

Outside of anaphylaxis, IgE reactions and coeliac disease, testing for other sensitivities is limited.

The gold standard for identifying non-IgE reactions food sensitivities is the Diagnostic Elimination Diet developed by Royal Prince Albert Hospital (RAPH). This was ground breaking in it’s day, acknowledging that we can react to food in ways that significantly affect our health outside of IgE reactions.

BUT, being very restrictive to start with, it’s a super hard diet for many to follow.

There are a few other caveats with this diet too- it’s not suitable for everyone, it takes a long time (months, up to 6 month in some cases) and depends on you sticking to it and doing it well to be reliable.


What you’re not likely to get tested through your GP

Maybe you’ve gone to your doctor and had testing done that state you are fine, yet you still feel something you’re eating is contributing? Perhaps you were told there are no tests available once IgE reactions have been ruled out? Maybe you’ve asked about food sensitivity testing only to be told it’s all rubbish and a giant waste of time and money?

Currently there are no tests available for many compounds in our diet associated with causing reactions. Amines including histamine, salicylates, glutamates, oxalates and FODMAPS are all in this basket. We know they cause issues for many, but it’s not as simple as running a quick test for a yes/no answer.

Measuring your IgG reaction to foods is another option for identifying food sensitivities, but they’re rarely requested by medical professionals. These are known as type III allergies and are the delayed hypersensitivities we discussed earlier. In the medical field, debate still persists around the relevance of testing for IgG sensitivities so let’s explore that a bit further.


So why doesn’t medicine often acknowledge IgG food sensitivity testing?

One of the main reasons there is so much debate around IgG testing is that our understanding of food reactivity is still emerging. It doesn’t involve just one pathway in the body, and today’s science does not know all there is to know about how our immune system functions. The field of immunology is constantly changing as we learn more and adapt and update our understanding.

While most Allergists agree that IgG antibodies are created in response to foods, they don’t all agree that these immune complexes pose a problem. It’s debated that IgG levels are purely reflective of dietary intake as regional shifts are noted. There is definitely more chance the foods you will be reacting to are ones you eat more of, but this doesn’t explain why some foods test positive for people when it’s not a big part of their diet.

Another area that makes recognizing IgG testing murky is that there are different subtypes of IgG. There are actually four subtypes. Without getting too complicated we thought it was important to mention, as this is a key reason IgG testing can be written off as not relevant.

Some tests measure only IgG4, the subtype made in the tiniest amount, and believed to be a marker for tolerance (as it’s produced to reduce inflammation). However most IgG tests, including the one accessed by us, measure total IgG. This means it is predominately types 1-3 that will make up the total amount. Why is this important? Because types 1 and 3 have been shown to increase inflammation and stimulate the immune system, NOT reflect tolerance to a food.


Higher IgG antibodies have been associated with many different conditions such as:

  • IBS
  • Chron’s Disease
  • Asthma
  • Hayfever
  • Eczema
  • Atopic dermatitis
  • Migraines

IgG reactivity has been associated with higher incidence of leaky gut, or intestinal permeability. When our immune system makes an antibody to a food (it doesn’t matter if it’s IgG or IgE), they bind in the gut and disrupt your permeability. Even researchers skeptical of IgG testing noted there is strong evidence IgG Antibody levels rise with increasing gut issues.

Clinically over the years I’ve seen IgG testing be a game changer in helping clients identify their food triggers. They are not imperfect tests, but when used appropriately, by someone who knows how to interpret them accurately, they help identify foods that are a huge burden to the body.


How we approach testing

Helping steer you towards the most relevant tests for you is just one of the ways we can support in identifying food sensitivities. For some this may be dietary adjustments if we suspect one major food, or FODMAPS or salicylate intolerance from their symptom picture. For others it may be breath testing for lactose or fructose intolerance. Other times IgG Food sensitivity testing is the best option to begin working it all out.

Outside of testing options, we also bring over of 20 years of clinical experience to how we view your health. We have worked with a huge range of people and bodies over the years, and have supported with a range of elimination approaches.

Different things work for different people. Elimination diets are not for everyone. Some don’t have the discipline, some have additional health concerns and some have other things going on in life that mean it’s just not feasible.

Knowing you have other options for testing, and the support of someone who will meet you where you are at, can be all the difference needed to make a start.


To work with us click here. If you have a few more questions, you can book a Free 15min Health Strategy Chat.


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About Sandi

Sandi Cooper is an experienced Naturopath working in clinical practice for almost two decades. Her clients love her down-to-earth approach and her naturally caring qualities. Although Sandi is experienced in most areas of clinical practice, she has a special interest in children’s health and nutrition, working with parents to get the best outcomes for their children.

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