Gluten and Cross-ReactivityTricia Thompson
For the past several years there have been rumblings in the celiac disease community about gluten and foods that are “cross-reactive”. These foods supposedly include coffee, dairy, yeast, corn, millet, and rice.
Where does this information come from? The information comes from a study published in 2013 and co-authored by the Chief Scientific Advisor at Cyrex Laboratories. We’re not going to get into the weeds in this brief post but the full article entitled Cross-Reaction between Gliadin and Different Food and Tissue Antigens is available at https://www.scirp.org/pdf/fns_2013011516575568.pdf
How did study authors arrive at their conclusions about cross-reactivity between gluten and non gluten-containing foods? Briefly and as stated in the paper, they “measured the reactivity of affinity-purified polyclonal and monoclonal α-gliadin 33-mer peptide antibodies against gliadin and additional food antigens commonly consumed by patients on a GFD using ELISA and dot-blot.”
What does an expert have to say about this study? We reached out to Adrian Rogers for his opinion on the study findings. Adrian is a Senior Research Scientist at Romer Labs who has 17 years of immunoassay development experience, including the G12 antibody that was raised against the α-gliadin 33-mer peptide.
“I believe that the scientific methods used in this study are not best suited to answer the question of whether there is any cross-reactivity between gliadin and unrelated foods. The issue I have with the test methods used is that they can be prone to giving false positive results, if as in this case, there is a high amount of protein in the sample tested. I cannot rule out that what we are seeing in this publication are in fact artificial and misleading results caused by the test method used and does not reflect what happens in the body. I would like to see more rigorous studies completed using more appropriate methods that can answer specific questions about which particular individual proteins of each food may or may not be an issue.* We use the G12 antibody to determine the level of gluten in food and we would never make an assumption as to how this would relate to an individual with celiac disease.”
*The study Adrian would like to see: “A study I would like to see is a western blot of an SDS page gel of the food extracts, that way you can find out the particular individual proteins in the foods that the antibodies may or maybe not binding to.”
Bottom line: At this time there is no scientific basis for eliminating non gluten-containing foods from the gluten-free diet due to supposed cross-reactivity with gliadin.
Something to think about: If commercial gluten testing methods cross reacted with a large number of non gluten-containing foods, the manufacturers would not be able to sell them. In fact, kit manufacturers have to demonstrate that their assays do NOT cross react with non gluten proteins.
Hmm, idk, he gives a strong criticism of the methods, but doesn’t suggest a better method? Call me suspicious, but that sounds like he’s implying that the study was intended to be misleading. Such studies do exist, but I’m wondering why he didn’t say “they should’ve used this other method.” My interpretation of the study and his comments is that so far, this is the best we can do, unless someone comes forward with some better method. I’m all for that.
But we still use the old cabbage and vitamin C content study from the 1940s (or earlier?) to show why you shouldn’t cook veggies too long. I haven’t heard anyone say that we should’ve checked to see if DHAA (dehydroascorbic acid) was formed and the vitamin C was preserved after all, just a form that the methods couldn’t detect. In both cases, I’d be happy to see better research, but I don’t throw out the cabbage with the cabbage water. 🙂
It occurred to me later that I had read something about prolamins in quinoa activating an immune response similar to gluten. Not sure if this piece of the puzzle fits here, but there’s similarity. https://www.ncbi.nlm.nih.gov/pubmed/22760575 I know glutens are prolamins, but not all prolamins cause a gluten reaction. I’m kind of wondering how many more of these exist in nature, and if, by activating the HLA genes, it makes us prone to other reactions.
Angelica, this is what I posted about a year ago about this study on quinoa:
After reading the entire research article (Variable activation of immune response by quinoa prolamins in celiac disease. Am J Clin Nutr. Published ahead of print July 3, 2012), I am not all that concerned about quinoa. Here is a brief summary:
1. Fifteen quinoa cultivars were used in the research. They were provided in coordination with the germoplasm bank at the National Institute of Agricultural Research in Peru. There is no mention of whether the cultivars were assessed for contamination with wheat, barley,or rye. We know that quinoa may be dried under barley.
2. Prolamins were extracted from 15 quinoa samples, 3 wheat starch samples with known gluten content, 1 sorghum sample, and 1 millet sample using an immunobinding assay and screened for reactions against two anti-gliadin antibodies and two anti-high molecular weight glutenin antibodies . Reactions were graded as –, +, ++, or +++. Reactions for the quinoa cultivars were graded as — or + except for the cultivar Ayacuchana which had a ++ reaction to one of the anti-gliadin antibodies. By comparison, the wheat starch containing 10 ppm had antibody reactions graded as –. Wheat starch containing 30 to 60 ppm gluten had antibody reactions graded as ++. Wheat starch containing 100 to 250 ppm had antibody reactions graded as +++
3. Prolamins were extracted from 15 quinoa samples using a noncompetitive ELISA (the specific ELISA is not mentioned but it does not appear to be either the omega-gliadin or the R5). Four cultivars contained quantifiable gluten (reported as celiac-toxic peptides): Ayacuchana 2.56 ppm; LP-4B 1.38 ppm; INIA-Pasankalla 1.21 ppm; Witulla 1.64 ppm.
4. Ten T-cell lines were cultured. All ten demonstrated positive stimulation indexes when cultured with gliadin. Two of the ten T-cell lines cultured with cultivars of Ayacuchana and Pasankalla demonstrated positive stimulation indexes.
5. The authors conclude that, “… generally quinoa is safe for patients with CD. However, we observed large variability in the immune effects of protein, depending on the cultivar tested, as occurs with oats. Furthermore, we reported for the first time activation of gliadin-specific T cell lines by proteins from 2 quinoa cultivars after TG2 deamidation. It is conceivable that celiac-toxic peptides exist within quinoa proteins from these 2 cultivars, although potentially low numbers of toxic epitopes could be clinically irrelevant. However, without in vivo data, it is difficult to anticipate the effect of quinoa consumption in patients with CD; therefore, further investigation of quinoa including the amino acid profile (proline and glutamine), prolamin subfractions, and quinoa as a composite food within an in vivo feeding study will be needed to confirm the suitability of quinoa for patients with CD and to facilitate its full incorporation in the gluten-free market.”
Wow I had no idea about that barley issue with quinoa. I’ve been looking for a source of insoluble fiber and so I’ve been searching for a non-hulled quinoa. I really miss my raisin bran!
Angelica, Here is the link to more information on quinoa and barley https://www.glutenfreewatchdog.org/news/quinoa-and-possible-barley-contamination/. In our testing we haven’t found any issues with quinoa and barley contamination (all quinoa has tested < 20 ppm). The R5 ELISA "overestimates" gluten from barley, so if it was present in quinoa labeled gluten-free we would know.
That’s great news, thanks! I have been experimenting with making a gluten free sourdough and I noticed that quinoa seems to ferment very nicely. I’ll post about it if it works out, but I’m all thumbs with sourdough. I really appreciate your hard work!
Hi Angelica, In Adrian’s original statement for posting he included more detailed information about the study he would like to see. It was removed from the final statement to keep it simple. It read, “A study I would like to see is a western blot of an SDS page gel of the food extracts, that way you can find out the particular individual proteins in the foods that the antibodies may or maybe not binding to.”
Hi Angelica, to expand on what Tricia has said, to me it would be better to run a study similar to the one you cited taking a more clinical approach. The issue I have with the inhibition/competitive assays that were used in the original study is that if the sample you are testing contatins a high amount of protein this can inhibit the test method and lead to a false positive result. This can be avoided if you use a sandwhich assay format, which is the format that the majority of gliadin/gluten food test methods, available on the market, use.
Thanks for clarifying!
Bear with me a bit, I’m no wiz in the lab, as my first chem teacher will attest, but I’m headed to the weeds.
They used ELISA and Dot-blot instead of ELISA and Western Blot. The blots are used to confirm the ELISA result. (when you look these up, they use the example of HIV detection.) But sometimes you have too many samples to fit into an electrophoretic device’s lanes. Dot-blot is used when there are too many samples to fit into Western Blot. Which is the situation we have here. It’s also cheaper but more “noisy”.
While I’d love to see a multiple WB done on these samples (to fit all the antigens), I don’t think their use of dot-blot actually invalidates what they found.
Their substrate was separated by dialysis instead of electrophoresis into small and large molecules, which again is a cheaper way to do it. I’m not sure I’m ready to imagine a world where only the state of the art in science is given any credibility. Older simpler methods are still valid and when research funds allow, newer, more expensive ones will be welcome.
Dot blot vs Western Blot (for those, like me, who were lost on the why’s) https://blog.benchsci.com/dot-blot-principles
I guess my point is, that I don’t want to throw away what they found because their methods were less expensive. Those methods haven’t been invalidated and until they are, I’m putting some trust in them.
Western blots are used routinely in our industry and you can determine a lot more info, I use the same antibody in ELISAs and have never seen this degree of crossreactivity
I just want to echo the thank you to Adrian. I wasn’t being argumentative, just engaging in discourse, a nearly lost art. I will take it to heart that these results are probably overstated if others aren’t finding the same with other methods. However, I recognize that reproducibility would require that others use the same methods to confirm it. And since reproducing a study isn’t done very often, we may never even have confirmation from where to start a real debate on why the methods are different in this case.
From the perspective of patients though, these things don’t matter so much. The list of reactions provided by the study becomes a map of “possible” reactions, and if people don’t feel well eating something then of course they will attempt to avoid it. I see that study as a list of things people might begin to suspect, not as a list of things everyone with Celiac should avoid at all costs. That’s not something I consider to be healthy, and neither should anyone else.
I recognize that people get extreme about this subject, I think because it’s easier to be in the “resolution to avoid” state of mind than it is to be in the uncertainty of suspecting something should be avoided.
I avoided FODMAPs religiously until several months after my diagnosis, and I found that my sensitivity to it had dropped. I could still go over my tolerance, but it was better. Now, except if I have a gut infection, I can eat onion and garlic raw if I want. Just not 20 cloves. It’s frightful to think that people might totally ignore foods they have lost the reaction to because it’s simpler to have established rules. Variety is really important.
So thank you for giving your expert opinion and I have taken it to heart.
Thanks Angelica, I appreciate the discussion, I think it boils down to maybe not using the right tools for the job. With food analysis we really are trying to push a toolbox approach as there is no single method of analysis that can cover everything. I can only talk about the tools used in the study, I bow down to Tricia’s extensive knowledge and experience with regards to the clinical aspects. One thing I do know, especially with regards to food allergy, everyone is different, and external factors can also have an influence. The results of the TRACE study have just been published and it is fascinating https://www.food.gov.uk/news-alerts/news/peanut-allergies-affected-by-exercise-and-sleep-deprivation-new-study-finds
He does give an alternative.
The study Adrian would like to see: “A study I would like to see is a western blot of an SDS page gel of the food extracts, that way you can find out the particular individual proteins in the foods that the antibodies may or maybe not binding to.”
Hi Sue, As mentioned to Angelica in another comment, in Adrian’s original statement for posting he included more detailed information about the study he would like to see. It was removed from the final statement to keep it simple (it was added back after Angelica’s comment). This was my error.
So much “noise” being generated in the gluten-free community about cross-reactivity. Nice to have some more trusted scientific entities weigh in on this subject.
Thank you, Tricia and Adrian!
You are most welcome, Al. A huge thank you to Adrian for his willingness to speak up and out about these issues that continue to dog us in the gluten-free community!
What is the reaction to nightshades that celiacs are often cautioned about? Is that cross reaction or what?
I’m not familiar with cautions regarding nightshades. What is the source for this information?
While I doubt cross-reactivity, I would venture to say it is not uncommon for celiacs to develop food sensitivities or intolerances. These are not related to the gluten protein at all but more so to your damaged intestines and immune system often resulting in issues with certain foods.
A food Intolerance is usually the result of enzyme deficiencies. Intolerances don’t directly involve the immune system and normal happen when your digestive system is simply irritated by certain foods or cannot digest them.
A food sensitivity is a bit harder to explain and I have found it just sort of happens and your body just reacts to other foods. I myself and many others get these with other foods from Nightshades, Onions, Garlic, Peppers, Peanuts, Soy, etc. Symptoms can include, vomiting, migraines, brain fog, inflammation, digestive problems, and bloating. Personally, I get rolling issues where a type of food can be alright then randomly I have months of issues unable to eat it while others have been around for over 6 years.
I am currently experience a problem with rice. I’ve been fine with it for 5 years and now I can no longer tolerate it nor can I tolerate things made with rice flour. I’m having all of my glutening symptoms including severe fatigue, brain fog, body aches, headache, nausea and GI issues. One of my daughters and I both have celiac, so my whole family has been eating a lot of rice for meals, so I suspect that overuse caused this. Is there any more current research on this phenomenon and is it possible to heal it? I’m feeling sort of lost and confused about why this happened as well as the prospect of losing all rice products.
Jennifer, are you currently working with a dietitian or your gastroenterologist to try to determine the cause of your symptoms?
My GI can’t see me until February. So I am doing an elimation diet myself to try to stop the reaction.