The ins & outs of food sensitivity testing

This is a controversial topic, and there is no quick and accurate method for revealing food sensitivities.

But first, why would you consider pulling foods out of your diet? Because if your body is reacting to foods, this damages your gut and immunity, and causes inflammation, which is linked to 90% of disease and results in pain. In my practice I may pull certain foods out of a client’s diet while we heal their body, then reintroduce them again.

Allergy versus sensitivity

But before we begin, don’t get mixed up between food allergy testing and food sensitivity testing.

True allergic responses (Type 1) involve an immediate IgE immune response. ELISA, or enzyme linked immuno-sorbent assay, is considered the gold standard in food and other substance allergy testing. But in reality, it rates as fair with around 60% accuracy. What ELISA does is to tag IgE with an enzyme, with the more being produced indicating a stronger reaction.

RAST is an older technology also used for IgE testing. But skin prick testing (SPT) is the most frequently used method due to its rapidity, simplicity and low cost. But it has low predictive accuracy of less than 50%.

Food sensitivity testing

Food sensitivity testing, on the other hand, measures delayed responses to foods for up to 3 days after consumption, and involves different immune system responses.

ALCAT & MRT

For this, some people like to use the ALCAT or MRT tests.

ALCAT, or antigen leukocyte cellular antibody testing, assesses the body’s cellular response to challenges from a wide array of substances like food by measuring changes in white cell size. While double blind oral tests show an 86% accuracy it uses older technology, has a poor split sample reproducibility (the same blood sample doesn’t show the same results when tested twice) and doesn’t have the capacity to measure adaptive immune (T-cell and NK cell) responses.

MRT, or mediator release testing, is a more advanced version and measures changes in the ratio of liquids to solids after whole blood exposure to various antigens. The lab that created it claims it’s 94.5% sensitive, with a specificity of 91.7%. It also claims split sample reproducibility consistently exceeds 90%. It’s not available in Australia and is banned in some US states.

Type 3 Food Sensitivity testing – IgG, IgM, IgA

Then there’s Type 3 food sensitivity testing.

Antibodies produced to a food attach to antigens creating a chain or complex and form IgM or IgG antibodies, as well as specific food antigens.

How it works is that IgM – the first antibody secreted by the adaptive immune system in response to a foreign antigen, thus serving as the first line of host defence against infections but also playing an important role in immune regulation and immunological tolerance – lasts several weeks before converting to IgG antibodies.

IgM is not usually tested in relation to food sensitivities, but IgG is commonly used, and ELISA is the most common method.

The problem is that IgG reactions can be protective e.g. in some Type 1 food allergies, high levels of IgG can block reactions from occurring. In other words, IgG levels can go up as the severity of an allergic reaction (IgE) goes down.

IgA testing is also used to assess food sensitivities. IgA is the first line of defence against infection by preventing bacterial and viral adhesion to epithelial (our protective body surface lining) cells and by neutralisating them. This testing shows damaged mucosal reactions in the mouth, nose, lungs, stomach and intestines, bladder and more.

For identifying food sensitivities, I have not found any testing to be as reliable as elimination diets. But I do use combined IgG and IgA testing on occasion when general eradication has been achieved by a client yet a food response is ongoing.

What exactly gets tested?

Most food sensitivity testing is done with raw food only. This is problematic because proteins in food change when cooked, therefore you may react to food in either or both forms. This means that most testing gives you only part of the picture.

Elimination diet

The truly gold standard practice of identifying food sensitivities involves a temporary elimination diet followed by the controlled reintroduction of foods. Foods suspected of causing symptoms are removed from the diet – commonly gluten/gliadin, dairy, corn, soy, sugar – and when symptoms are gone after 2-3 weeks, only that food is reintroduced to see if symptoms return.

listening to your body

Also, I find listening to the body useful. If something suddenly tastes bad or smells off to you, your body probably doesn’t want or need it at that time. Your taste system (when it’s not being manipulated by big food) can be your body’s barometer to what is or isn’t the best thing to be eating.

food sensitivities don’t need to be forever

Also remember that just because you might have a sensitivity to a food now, it doesn’t mean this is for life. Resting from foods you are sensitive to for six months while you heal your gut and strengthen your liver can reverse sensitivities.