Five Keys to Improve Reliability of Food Sensitivity Testing

Food intolerances or sensitivities (I am using those words interchangeably here),  are becoming more and more known and accepted as a real condition or diagnosis.  We used to only know about allergies to foods such as shellfish or peanuts for example where the responses are immediate, significant,  even life threatening.  Food sensitivity, on the other hand, results in reactions that are slower to respond taking hours or even days, the severity of response  lies within a very broad spectrum from barely detectable to strong but is almost never life threatening and the resolution of reaction can also be slow from many hours to even days.

The culprit of a classic, Type 1 food allergy is almost always known because of the immediate and severe response to that food.  Finding the culprit foods that you may be intolerant to can be a much more difficult task and an actual journey of discovery not only because of the slow and less severe response but also because of the multiple pathways that your immune system can choose from to manifest the response.

Food sensitivity testing has become increasingly popular to do but often the tester is left with the same or even more confusion than when she started.  Here are a few critical keys to keep in mind when getting ready to do food sensitivity testing.

1.  Learn About the Integrity of Your Gut Lining

This is so important.  A damaged intestinal lining that has loose connections between cells and poor enzyme function is allowing larger particles of food to pass through to the blood stream.  Here, the immune system, in its protective manner deems these particles as foreign and even dangerous and sets up antibody responses to begin the destruction process of these food particles.

A common finding with food sensitivity testing is that many foods are positive, ten, twelve or even more and this is a tip off that the gut lining has lost its integrity.  Although these results are helpful to indicate this damaged gut status, it doesn’t help the tester discover which foods are most problematic.  For this reason, I prefer to learn more about my patient’s intestinal permeability first, treat to heal the gut lining and then do food sensitivity testing down the road.

2.  First Know Your Ability to Produce Antibodies

The two primary antibodies that we are looking at when it comes to food sensitivity response are called immunoglobulin G and A. (IgG and IgA).  It isn’t unusual for someone to be deficient in their ability to produce these antibodies in general.  Among the reasons for this include genetics  and stress.  If you don’t know that you are someone who has a diminished ability to produce either or both of these antibodies and your test results come out with primarily negative results, these may in fact be falsely negative.

Knowing your IgG and IgA production capacity first allows me to more accurately interpret your food sensitivity test results!  Sometimes we even opt out of testing if your antibody production is extremely low because the results will not provide us with additional clarity.

3.  Know Which Antibodies You Are Testing

Many times I have heard patients say, “well, I know that I don’t have any food intolerances because the allergist tested me for that in his office and they were all negative!”  In this instance, almost always the test that has been done is the skin scratch test which is looking for a Type 1 allergy that is an immediate and severe response.  These types of responses are mediated by immunoglobulin E (IgE).  Delayed food sensitivities are mediated by IgG’s and IgA’s  So, a skin scratch test would not be helpful to reveal food intolerances nor would a blood test looking at IgE responses.

multipletesttubes4.  Do the Right Test

All of the information in #3 above applies here as well.   Additionally, it’s important to know that traditional blood testing for gluten sensitivity is only testing for particular constituents and molecular forms of the gluten protein called gliadin and is considerably incomplete.  For these reasons, the traditional blood test often comes up negative and falsely informs the practitioner and patient that gluten is safe for him or her to eat!

Cyrex Labs has the most advanced testing for gluten sensitivity to date.  It includes testing for 3 isomeric forms of gliadin, one of the gluten proteins but also tests for immune reaction against 2 other wheat proteins, the wheat germ lectin and glutenin.  This test is also looking at immune reactivity to gut enzyme/gluten complexes and other physiology that relates to gluten ingestion.

Thirdly, your food intolerance reaction could occur by the IgG pathway or the IgA pathway.  IgA antibodies are more present in a mucus membrane environment like the digestive tract.  If you are experiencing more digestion related symptoms then it would be important to do testing that includes results for IgA antibody responses

5.  Eat the Food You Are Testing For

If you are wondering if 1 or more foods in particular are causing you problems then make sure to eat those foods not just the 5- 10 days before the test but all the way back to 5-6 weeks before your test.  It’s the slow build up of the antibodies from exposure further back that is most important not to miss. Many practitioners will tell you to eat the suspected foods anywhere from 1 week, 10 days or maybe 2 weeks before your test, but I have recently learned that if a slow-to-build IgG antibody is your primary responder, you may miss it if you haven’t eaten that food far enough back before your test, the antibody may still be building in your system.

There is an exception to this rule.  There are more than a handful of times when someone comes to me to have food sensitivity testing done for a particular food because they are experiencing very challenging health issues.  Many times that person will tell me that they already have eliminated several foods but that they really don’t know which food is a problem.  If their health challenges are significant enough I won’t recommend adding that food back, particularly if it is gluten and sometimes even dairy because these foods have such strong ability to mount an immune response which can be difficult to turn off.  Blood testing for these two foods in this case may not be warranted.

I hope you can see that food sensitivity testing is not a straight forward method of gathering clear results about your responses to food. It is an area in health care that demonstrates the concept of biochemical individuality and even fluctuation of response within the same person.  I like to approach the discovery of food intolerances not only as a science but also as an art! I hope these keys have been helpful for you and I would love to hear about your food sensitivity testing experiences!

About Sheila Wagner PT, CN, BCHN

Sheila’s cutting edge ability to uncover hidden source(s) of health issues when no one else has is the first piece to her step wise approach in solving your persistent health complaints.

+Sheila Wagner is the ultimate expert assisting people nationwide to finally fix their health through 1:1 consults, group programs, lectures and classes.

Opinions & Feedback:

  1. It’s hard to find well-informed people for this topic, however, you sound like you knw what you’re talking about!

  2. Well it’s 4:30 am and I cannot sleep. I just got the results of my food sensitivity test(iga) and its seems I am sensitive to everything! I have an autoimmune disease either RA or Lupus, so I already it grain free and sugar free. My tests shows I am highly sensitive to dairy, goats milk, cocoa, gluten, vanilla, coffee and on and on. I’m even sensitive to all lettuce, except iceberg, so now I can’t have a healthy salad. I’m completely overwhelmed! Is this test truly valid. I’m willing to give up these foods, but I need to know its a valid test and my overall health will improve. Please please advise. Thank you!

    • Kate – the fact that you responded to so many foods on a sensitivity test indicates that most likely you have increased permeability at your intestinal lining which Dr. Fasano has shown is a criterion and trigger for autoimmune disease. Its important to embark on healing your lining and entering the process of sleuthing out which food are true problems or not. It is a process and an art – I’d be happy to work with you.

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