What is the distinction between IgG and IgA antibodies?
- A primary piece to understanding antibodies is their area of origin. IgA antibodies are produced by saliva, tears, and mucous linings in the lungs and the intestines. IgG antibodies are the most abundant in serum and are produced by almost every cell in the body. IgG antibodies can cross the placenta. These antibodies also have considerably different half-lives. IgA antibodies have a half-life of ~6 days. Elevated IgA antibodies indicate exposure 8-12 days ago. The half-life of IgG is much longer and individually variable and can indicate prolonged exposure/sensitivity.
- IgA antibodies are produced by the intestinal mucosa as a defense mechanism. If IgA antibodies are elevated to a particular protein (antigen), this can indicate an immune response to mucosal irritation or damage. Elevated IgG antibodies means that there is exposure of these food to the bloodstream and the body is producing antibodies.
- In terms of food sensitivities and intestinal autoimmune disease, IgG antibodies can occur as a consequence of and can be downstream to intestinal permeability. These are likely correlated with more systemic immune responses (brain fog, fatigue, skin, migraines, etc).
- As with all immunoglobulin testing, it is important to evaluate the person’s baseline levels of (total) IgA and IgG. These biomarkers are included in the Wheat Zoomer.
What is the source of Food Sensitivity Antigens?
- The antigen Food Sensitivity test uses FDA-approved antigen extracts only. These antigens are sourced from organic raw foods.
- Testing raw food antigens is common and the most practical approach to identifying a patient’s response to a particular food. Cooking and processing foods can denature and change protein conformation. Different cooking methods, temperatures, and processing are extremely varied and are difficult and impractical to test in relation to an individual’s response to food.
- Food sensitivity testing should only be interpreted in conjunction with a patient’s symptoms.
Why is “wheat” not tested on the Food Sensitivity test?
- While our Food Sensitivity test is also run on our microchip platform and has great reproducibility, it is a PROTEIN level antibody test. This is different than our Wheat Zoomer, where we have synthesized the entire wheat proteome at the PEPTIDE level. Thus, the Wheat Zoomer is such a magnified look at how our immune system can react to wheat, there’s no way looking at a single “wheat” protein antigen can offer that same view. We did not want to offer something inferior to our Wheat Zoomer test.
- Another reason why wheat and gluten sensitivity testing has been so challenging, to date, is that the gliadin protein in gluten is not water-soluble. Most manufactured antigens use water as a solvent. Even though we are using FDA-approved/sourced antigens on our Food Sensitivity, there is really no way to tell how much gliadin is actually contained within and making the leap of wheat antibodies to true gluten sensitivity could be erroneous. This is, again, why our Wheat Zoomer is so great because these peptides are synthesized on the chip itself vs. being chemically extracted. For anyone trying to discover sensitivities to gluten and non-gluten wheat peptides, the Wheat Zoomer is 100% sensitive and is the test to run.
How are reference ranges for the Food Sensitivity determined?
- We have given a numerical value to quantify the antibodies measured by chemiluminescent signal of our microchip
- The determination of the positive cutoff is by 97.5 percentile of 192 normal healthy controls.
- If you are above 97.5 percentile, you are considered positive.
- If 5% below cutoff (92.5-97.5 percentile), it’s borderline.
- Less than 92.5 percentile, it’s negative.
Descriptions/Specifics for Antigens tested
- Squash antigen-specific for yellow squash
- Lettuce antigen is specific for romaine lettuce
- Egg antigen contains both ovalbumin and ovomucoid
How can I be positive for antibodies to beta-casein but not cow’s milk?
Antibodies to beta-casein require one to eliminate cow’s milk foods, even if one is not sensitive to whole cow’s milk protein. Cow’s milk protein will eventually be enzymatically broken down into peptides, one of which is beta-casein.
What if my test shows that I have had a reaction to vanilla (pecan, etc), but I don’t have vanilla that often and can’t remember the last time I have had it?
In the course of our daily lives – eating out in restaurants, buying packaged/processed foods, having dinner at someone else’s house, etc, we are constantly in contact with trace amounts of proteins from other foods. This is especially common at a restaurant, where counters and food prep spaces might have had a host of different foods on them prior to your meal being served. You might be familiar with the terminology “this food was processed in a facility that also processes nuts, dairy, wheat…” or similar wording that is warning you that the food item might be contaminated with trace amounts of other foods. It can be also that you have routinely come into contact with food that has been contaminated with other items such as vanilla, nuts, etc.
My Food Sensitivity results show no reaction to wheat, but my Wheat Zoomer shows a reaction to wheat. Are my results wrong?
While our Food Sensitivity test is run on our microchip platform and has great reproducibility (the highest in the industry), it is a PROTEIN level antibody test. This is different from our Wheat Zoomer, where we have synthesized the entire wheat proteome at the PEPTIDE level. Thus, the Wheat Zoomer is such a magnified look at how our immune system can react to wheat, there’s no way looking at a single “wheat” protein antigen can offer that same view.
I have a known allergy, but tested negative for this food on Food Sensitivity? How can that be?
The terms food allergy and food sensitivity are widely confused and often wrongfully used interchangeably. A true food allergy (type I hypersensitivity or immediate reaction) is usually mediated by an IgE-specific antibody. On the Food Sensitivity test, we are measuring both IgG and IgA antibodies that are more indicative of food sensitivity (type 2, 3, or 4 hypersensitivities or delayed reaction). For a full explanation of the difference between food immunoglobulins, please see this attached handout.