Food Allergy vs Food Sensitivity? What’s the Difference? Does it Even Matter?

Did you know that true food allergies and food intolerances, or sensitivities, are actually different conditions?

As gluten free diets have gone main stream the concept of what constitutes a food allergy vs a food sensitivity has become blurred. Now don’t get me wrong, as anyone who has been to our clinic will know, I am a big advocate of gluten free living. In fact I strongly believe that the sooner we discard wheat and cow’s milk the healthier we will be.

Unfortunately, when many people consider the switch to a wheat free and milk free diet they are deterred because their GP tests for food allergies, rather than food sensitivities. This leaves people trapped in a life of ill health and disease because of the difficulties associated with diagnosing food sensitivities.

In Australia, we have the dubious honour of having one of the highest rates of allergy in the world [1]. Despite this, true food allergy is still relatively rare effecting 1 in 20 children and 1 in 100 adults. On the other hand, the figures for food intolerance or sensitivity is much higher. Over 1 in 4 of the population report some form of sensitivity or intolerance.

When you see a list of common allergens and common causes of food intolerance side by side, it’s not hard to understand the confusion. There’s quite a lot of overlap with the big three included in both the list of common allergens and the common intolerances:

  • gluten
  • soy
  • casein (milk)
Common Sources of Food Allergens Common Sources of Food Intolerances
peanuts, milk, gluten, fish, grains, soy, shell fish lactose, milk, wheat, gluten, yeast, soy, corn, nightshades, fructose.

Despite the rather understandable confusion it’s important to know the difference as many people are living with long term bad health because the wrong tests are being done.

Definition of a Food Allergy

A true food allergy is best defined as a reaction to food where there is a immunoglobulin IgE controlled response. These are typically very fast acting responses with symptoms starting within minutes of exposure to an allergen. They can be life threatening with symptoms, ranging from itching, burning, and skin rash on the mild end, to anaphylactic shock on the serious end.

If you have school aged children you are probably familiar with rules limiting peanut and peanut based products in Queensland schools. This is largely due to the high incidence of food allergies to peanuts resulting in anaphylaxis.

For people with a food allergy there is no safe level of exposure. Any exposure will trigger a response even after elimination of the food for a long period of time.

Definition of a Food Intolerance or Sensitivity

In contrast to a food allergy a food intolerance or sensitivity does not involve an IgE response. A food intolerance may not even involve the immune system at all. In some cases a food intolerance may just be an inability to digest or break down a certain food, this is commonly the case with a lactose intolerance. This could result in symptoms as varied as:

  • diarrhoea
  • abdominal cramping
  • headaches and migraines
  • breathing problems
  • skin rashes and eczema

In other cases an immune reaction may be present. In this case the immune response is an IgG based immune response.

Food intolerance are often much slower to show symptoms than true food allergies. While an allergic response will be noted within minutes, intolerances can take hours to days to show symptoms. Food intolerances are also often dose dependent. People with an intolerance may be symptom free when exposed to small doses after elimination the food from the diet for some time.

How We Test & Treat Food Sensitivities & Intolerances

The rapid response between exposure and the onset of symptoms of food allergies means that the diagnosis of a food allergy tends to come quite early in life. Diagnosing food intolerances on the other hand is considerably more difficult. Often these only come later in life after ongoing, lingering health problems that can never quite be treated or explained.

The gap of hours and sometimes days between exposure and the appearance of symptoms combined with the dose dependent nature of symptoms, often means that even elimination diets and diet / symptom diaries are of limited value. They may give clues that something is wrong but still make it difficult to pinpoint problem foods.

The fact that many of the common food intolerances are foods that are eaten every day and several times per day, means that I often find undiagnosed food intolerances and sensitivities to be the real cause of symptoms often just chalked up as part of ageing. Muscular aches and pains, poor memory and brain fog, and sore joints are all common manifestations of food intolerance.

Diagnosis: The First Step

The first step is to identify that there is a problem. Eating is something that we do so frequently, that I have come to the belief that unless there is a genetic reason or an accident, the most likely explanation for sickness is food. I struggle to think of a single chronic disease that cannot be tracked back to too much of the wrong foods, or too little of the right foods.

I use live blood analysis in our clinic which may indicate the presence of food allergies and food intolerances through their effect on the immune system.

The results of live blood analysis on their own won’t indicate exactly which foods are causing problems, but combined with a dietary history it will offer clues where to start.


Unlike food allergies, food intolerances and sensitivities respond well to dietary changes. One of the first starting points is to remove what I refer to as the toxic trio. The toxic trio are three food groups that contribute to nearly 100% of the food intolerances that I see in clients. The toxic trio are:

  • Wheat and wheat products including bread, pastries, and cereals
  • Cow’s milk and associated products
  • Soy foods such as tofu, and soy containing products including Soy Milk

The majority of clients will experience enormous improvements in their overall health within two to four weeks by just removing these three sources of common allergens.

Further Testing

Sometimes though, there’s more that needs to be done. In some cases even after removing these foods live blood analysis shows that the immune system is still highly activated and symptoms still persist.

In these cases we may do more specific testing based on measuring the IgG response to certain foods. This will indicate specific foods that are causing problems and includes testing of foods such as:

  • Corn, rye, wheat
  • Nuts and beans
  • Meats & Fish
  • Fruit & Vegetables
  • Herbs, Spices & Teas

This testing can also measure the severity of the reaction, indicating whether a food needs to be removed permantely or whether it can be re-introduced after a de-sensitization period.

Reintroducing Foods

One of the first questions I often hear from people that have removed problems foods from their diet is when can they begin to re-introduce foods. This is particularly true with wheat and cow’s milk that form the basis of so many of our comfort foods.

I make no secret about being anti-wheat and anti-cow’s milk. Personally, I will never understand why someone would want to re-introduce these two foods after experiencing how amazing they can feel without them, but, the great thing about food intolerances vs food allergies, is that they can be treated. I’ve spoken about treatment for food intolerances before, which you can find here.

If you do decide that you want to reintroduce foods you may have been intolerant to make sure:

  1. You have given your body a nice solid break from them, at least three to four months
  2. You have been working to repair your gut lining from previous irritants.
  3. You introduce foods slowly allowing at least three days between each food group to monitor for adverse reactions.

When re-introducing foods I recommend clients keep a diet and symptom diary to help catch any foods that are likely to cause problems. I often say that the first sign a food doesn’t agree with you can be seen in the bowels so be sure to monitor bowel habits.

If you would like a copy of the Diet & Symptom Diary I use in our clinic just fill out this form and I’ll send you one.