Sourdough Wheat Bread is NOT Safe for Folks with Celiac Disease

Sourdough Wheat Bread is NOT Safe for Folks with Celiac Disease

Gluten Free Watchdog has tested three artisanal sourdough breads for gluten. We will not be testing any additional varieties. As the test results prove, wheat-based sourdough bread, including those made in small bakeries by artisanal bakers contains a lot of gluten and should not be eaten by anyone with a gluten related disorder. Full Stop.

Test results:

  • Product: Dan the Baker Country Sourdough Bread
  • Test date: April 2015
  • Why product was tested:  At the time of testing the bakery website included a page entitled “Sourdough for Celiacs”which as of April 6, 2015 stated: “A recent study based out of Italy shows that 80% of those with doctor-confirmed celiac disease can eat sourdough bread every day and experience no adverse symptoms. In sourdough bread, the concentration of gluten is decreased by about 97% …Eating sourdough can be a safe and healthy way to consume grains for nearly everyone, even 80% of those diagnosed with celiac disease as evidenced by the Italian study.”*
  • Ingredients: Water, Wheat flour, Ohio whole wheat flour, Sea salt, Wild yeast, Brown rice flour, Olive oil–trace amounts
  • Test results using the sandwich R5 ELISA (measures intact gluten): 104,000 parts per million of gluten

 

  • Product: Purbread Gluten Neutralized Bread
  • Test date: March 2016
  • Why product was tested: At the time of testing, literature in the bread display area read: Neutralized is defined by the manufacturer as making something ineffective or harmless. “Gluten now has been neutralized.” The manufacturer was also claiming that “celiacs” enjoy his bread without reaction.
  • Ingredients: Sour dough starter, Gluten neutralized white winter wheat, Raw pure honey, Pure maple syrup, Pure canola oil, Sea salt
  • Test results using the sandwich R5 ELISA: > 84 ppm gluten
  • Test results using the competitive R5 ELISA (used to detect gluten protein fragments): > 283 ppm gluten
  • Note: The actual gluten level of this bread is likely much higher. We did not have the lab dilute the sample to bring the results in line with the standard curve as we did with the loaf of sourdough bread from Dan the Baker. It is not necessary to have the lab run additional tests to know that this bread is not safe for individuals with celiac disease or other gluten-related disorders.

 

  • Product: Leaven Breads 100% Sourdough Bread
  • Test date: February 2018
  • Why product was tested: At the time of testing the website read, “There is a growing body of science showing how the sourdough process produces bread that can be handled by those with gluten-sensitivities, even though the bread isn’t gluten-free. If diagnosed with celiac disease, you should avoid this and all bread made with wheat flour. For more information, check out this article on the history of sourdough and celiac disease.” At the time of testing the homepage also read, “All our breads our sourdough, but they are not sour.  We believe in the power of local fermentation to leaven our doughs without the use of commercial yeast.  This creates a more complex flavor with a long proofing process and breaks down the gluten in flour naturally.”
  • Ingredients: Flour, Water, Salt
  • Test results using the sandwich R5 ELISA: > 84 ppm gluten
  • Test results using the competitive R5 ELISA: > 283 ppm gluten
  • Note: As with Purbread, the actual gluten level of this bread is likely much higher. We did not have the lab dilute the sample to bring the results in line with the standard curve as we did with the loaf of sourdough bread from Dan the Baker. It is not necessary to have the lab run additional tests to know that this bread is not safe for individuals with celiac disease or other gluten-related disorders.

* The study referenced on the Dan the Baker website is a 2011 study by researchers Greco et al.

  • What the researchers actually report: When two study participants ate baked goods made using extensively hydrolyzed flour (gluten reduced 97% and containing 2,480 ppm gluten) no clinical complaints were reported BUT they developed SUBTOTAL ATROPHY of their intestinal mucosa. In other words (and not surprisingly) these products are NOT safe for people with celiac disease. The researchers write, “Two CD patients consumed 200 g of S1BG that contained ~ 2480 +/- 86 ppm of residual gluten. They had no clinical complaints during the 60 days. One showed increased antibodies and both showed increased CD3 and gamma-delta intraepithelial lymphocytes with subtotal atrophy after challenge.”
  • The products that the study researchers believe may have potential use in gluten-free diets are those that have been fully hydrolyzed (8 parts per million of gluten) through sourdough lactobacilli and fungal proteases.
  • To read the full article, click HERE.

Please feel free to share this post with any bakers who claim their artisanal wheat-based sourdough bread is okay for folks with a gluten related disorder.

 

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Comments (29)

  • Helen Weems
    Reply

    I always appreciate your scientific findings, in a world dominated by internet blather. Very helpful!

    February 19, 2018 at 4:38 pm
  • Ken Reply

    Thank you again for your hard work and advocacy.

    February 19, 2018 at 6:04 pm
  • Ann Reply

    You’re always on the ball Tricia and we appreciate it!

    February 19, 2018 at 11:58 pm
  • Sharon kane Reply

    The first time I heard that sourdough wheat was safe for celiacs, I said “show me the test data”. Especially since my home baked sourdough rye bread was making me sick. Gave up all gluten and got my life back. Thanks for testing these terribly unsafe breads. Meanwhile I developed a gluten free sourdough technique and a have small baking business in my own dedicated gfree facility. You never know where your journey will take you.

    February 20, 2018 at 1:48 am
  • Jean Reply

    Tricia –
    Thanks for your efforts in protecting the celiac community.

    February 20, 2018 at 1:23 pm
  • Maureen Burke Reply

    Tricia, can I share this link in my newsletter?

    February 20, 2018 at 4:56 pm
  • Nicole Reply

    Did you check how long the fermentation time of these products was?

    May 14, 2018 at 6:16 pm
    • Tricia Thompson Reply

      All 3 of these breads are artisanal with supposedly long fermentations. None of them are close to being gluten-free.

      May 14, 2018 at 7:02 pm
  • Elise Reply

    The first bread is not a true sourdough because it has yeast. The first and second breads have oil added which doesn’t mean they aren’t a true sourdough necessarily but I have never seen a true sourdough bread add oil. The last is the only one that seems to be a true sourdough as far as ingredients but doesn’t say “cultured” or “starter” and doesn’t actually say what kind of flour. It needs to be whole wheat or some other whole grain. There is a much better study conducted in Europe that shows the difference between people with Celiac eating sourdough bread with baker’s yeast vs true sourdough bread had amazing results.

    “One study that examined how celiacs tolerate true sourdough bread was conducted in Europe. 17 people suffering from celiac disease were given 2 grams of gluten containing bread risen with either baker’s yeast or a normal lactobacilli culture. 13 of the 17 showed negative changes in intestinal permeability consistent with celiac disease. 4 people did not show any negative changes.

    Then, the 17 study participants were given true sourdough bread risen with a special lactobacilli culture able to hydrolyze the 33-mer peptide which is the primary amino acid building block that causes an immune response in people with celiac disease. None showed any negative changes in their intestinal permeability after consuming the bread which was made up of 30% wheat flour and a mix of oat, millet, and buckwheat flour.”

    This study of course only had 17 participants so is much to small to base any recommendations on but would be interesting to this on a much larger scale.

    July 1, 2018 at 4:34 pm
    • Tricia Thompson Reply

      All three breads are sourdough breads–relying on naturally occurring wild yeast (this is not baker’s yeast) and lactobacilli. To learn more, research wild yeast or sourdough starter.

      If you visit PubMed and search under celiac disease, gluten, sourdough, a number of scientific studies will come up. There is an ongoing effort to determine how to hydrolyze wheat to such an extent that it is not problematic to folks with celiac disease. All of these studies are conducted under laboratory conditions. None of the products used in these studies is artisanal sourdough wheat bread.

      Here is the abstract (As a side note: folks, if you have celiac disease or a gluten-related disorder–meaning you cannot eat gluten versus another component in wheat–then you can’t eat sourdough wheat bread):

      This work was aimed at producing a sourdough bread that is tolerated by celiac sprue (CS) patients. Selected sourdough lactobacilli had specialized peptidases capable of hydrolyzing Pro-rich peptides, including the 33-mer peptide, the most potent inducer of gut-derived human T-cell lines in CS patients. This epitope, the most important in CS, was hydrolyzed completely after treatment with cells and their cytoplasmic extracts (CE). A sourdough made from a mixture of wheat (30%) and nontoxic oat, millet, and buckwheat flours was started with lactobacilli. After 24 h of fermentation, wheat gliadins and low-molecular-mass, alcohol-soluble polypeptides were hydrolyzed almost totally. Proteins were extracted from sourdough and used to produce a peptic-tryptic digest for in vitro agglutination tests on K 562(S) subclone cells of human origin. The minimal agglutinating activity was ca. 250 times higher than that of doughs chemically acidified or started with baker’s yeast. Two types of bread, containing ca. 2 g of gluten, were produced with baker’s yeast or lactobacilli and CE and used for an in vivo double-blind acute challenge of CS patients. Thirteen of the 17 patients showed a marked alteration of intestinal permeability after ingestion of baker’s yeast bread. When fed the sourdough bread, the same 13 patients had values for excreted rhamnose and lactulose that did not differ significantly from the baseline values. The other 4 of the 17 CS patients did not respond to gluten after ingesting the baker’s yeast or sourdough bread. These results showed that a bread biotechnology that uses selected lactobacilli, nontoxic flours, and a long fermentation time is a novel tool for decreasing the level of gluten intolerance in humans.

      July 2, 2018 at 1:01 pm
      • Darby Reply

        You say: “As a side note: folks, if you have celiac disease or a gluten-related disorder, then you can’t eat sourdough wheat bread”

        The study you quote says: “Thirteen of the 17 patients showed a marked alteration of intestinal permeability after ingestion of baker’s yeast bread. When fed the sourdough bread, the same 13 patients had values for excreted rhamnose and lactulose that did not differ significantly from the baseline values. The other 4 of the 17 CS patients did not respond to gluten after ingesting the baker’s yeast or sourdough bread. These results showed that a bread biotechnology that uses selected lactobacilli, nontoxic flours, and a long fermentation time is a novel tool for decreasing the level of gluten intolerance in humans.”

        July 5, 2018 at 4:51 am
        • Tricia Thompson Reply

          Darby, the study is available in full (free). Please read it. By doing so you will understand (among other things) what the researchers mean by “selected lactobacilli” and “non toxic flours” and “sourdough bread.” Again, if you visit PubMed and search under celiac disease, gluten, sourdough, a number of scientific studies will come up. There is an ongoing effort to determine how to hydrolyze wheat to such an extent that it is not problematic to folks with celiac disease. All of these studies are conducted under laboratory conditions. None of the products used in these studies is artisanal sourdough wheat bread (or any bread you might make in your own kitchen).

          To future folks interested in commenting on this thread in favor of tradition wheat based sourdough bread and its safety for folks with celiac disease, please don’t until you read any study you wish to cite in full–not just the abstract. Speaking as someone who has written many abstracts, they are simply a summary with word limits of a couple hundred words. You must read the full study.

          July 5, 2018 at 12:50 pm
  • Chris Reply

    Just curious – How do they go about making “fully” hydrolyzed bread? Is it because of the starter they use? Length of time they allow it to ferment? Something different?

    I’ve read several of these studies and they all seem to gloss that part over so figured I’d ask. Thank you!

    October 26, 2018 at 2:33 am
    • Tricia Thompson Reply

      They don’t. In the Greco study, wheat flour hydrolyzed under laboratory conditions by sourdough lactobacilli and fungal enzymes was used to make the bread. However, it is unclear whether researchers tested the flour using a competitive ELISA. A sandwich ELISA would not detect smaller gluten protein fragments that result from fermentation/hydrolysis. In addition, because the gluten content of the flour is so low, structuring agents had to be added to the bread. In other words, this is not commercially available sourdough bread.

      October 26, 2018 at 1:34 pm
  • Katheryn Reply

    Reports of decreased sensitivity are heavily reliant on fermentation time and method. This is critical to the information regarding gluten contents. Also, there are other factors at play here (phytic acid, etc.) and not simply remaining gluten content that will contribute to whether or not they would be tolerated by -some- individuals that couldn’t otherwise. A typical “long” fermentation by a bakery will not go into the range that was reported in most of the available studies. Reports indicate minimal 24 hours and up to 3-4 days after the initial long bulk fermentation. Without this information, you can’t fully be confident in the result that you are getting. There is some promising results with all of the correct variables given. Something that may help many in the future. (I am a research biologist that works in the area of gluten sensitivity at a major University. Certainly appreciate the details here, but I think it is important that the wrong message not be translated from incomplete variable testing.)

    November 5, 2018 at 5:50 pm
    • Tricia Thompson Reply

      Sourdough wheat breads–long fermentation or not–are not suitable for folks with celiac disease. The belief that they are safe stems from a misread of studies on wheat flour hydrolyzed under laboratory conditions. One study (https://www.cghjournal.org/article/S1542-3565(10)00987-0/pdf) found that wheat flour fermented with sourdough lactobacilli reduced the intact gluten content of wheat flour to under 2,500 parts per million. Wheat flour contains approximately 100,000 parts per million of gluten. Under the FDA’s gluten-free labeling rules, foods making a gluten-free claim on product packaging must contain less than 20 parts per million of gluten. In this same study wheat flour fermented with sourdough lactobacilli and fungal proteases decreased the intact gluten content to under 10 parts per million.

      HOWEVER, sourdough wheat bread is not made using completely hydrolyzed wheat flour. You can not make what is typically thought of as a sourdough wheat bread product with a wheat flour that has a gluten content under 10 parts per million unless other ingredients are added to the flour to add structure. As the above-mentioned study states, “… the hydrolyzed flour is suitable for making sweet baked goods and also bread and pasta if supplemented with gluten-free structuring agents.”

      Sourdough wheat bread made in an artisanal bakery is not using hydrolyzed wheat flour to make their bread.

      November 5, 2018 at 6:15 pm
  • Deborah Scragg Reply

    The Italian study was interesting but certainly didn’t prove that coeliacs can go ahead and eat sourdough bread. It was a small study as these things often are to answer a wide research question and focus further research. It’s hugely misleading and irresponsible to advertise sourdough bread on this basis.
    Unfortunately your atticle did not make this clear and just set out to rubbish the exciting possibilities that sourdough may offer in the future. Your ‘research’ did not sound as valid as the research conducted in Europe yet you made assertations based on very dodgy evidence. Quite like the folks who claimed their bread was safe to eat!

    November 6, 2018 at 1:06 pm
    • Tricia Thompson Reply

      Not quite sure where to begin–our intent–and only intent–is to prevent folks with celiac disease and other gluten-related disorders from falling prey to what some artisanal bakers are telling folks about wheat-based sourdough breads. These breads should not be eaten by folks with celiac disease–full stop. As stated in the article “The products that the study researchers believe may have potential use in gluten-free diets are those that have been fully hydrolyzed (8 parts per million of gluten) through sourdough lactobacilli and fungal proteases.” We’ve tested 3 of these breads (part of what we do at GFWD is test foods for gluten)–breads that have been promoted to folks with celiac disease (one of which continues to be promoted as gluten neutralized–see https://www.glutenfreewatchdog.org/news/purbread-gluten-neutralized-bread-if-you-have-a-gluten-related-disorder-do-not-eat-this-bread/). If you consider testing food for gluten at a certified lab using formally validated scientific assays “dodgy evidence”…

      November 6, 2018 at 1:22 pm
  • Deborah Scragg Reply

    I think your intention is sound and I agree that false advertising and twisting the facts is totally wrong on the part of those bakers. I just felt it unnecessary for a valuable study to be misquoted to prove your point. Most people don’t take the time to look at the facts for themselves.

    November 6, 2018 at 1:49 pm
    • Tricia Thompson Reply

      Deborah, which valuable study was misquoted and how was it misquoted? The referenced and quoted study is mentioned because this is the study mischaracterized by various bakers. I do not deny that it is valuable but as stated in an earlier response, the study found that wheat flour fermented with sourdough lactobacilli reduced the intact gluten content of wheat flour to under 2,500 parts per million. Wheat flour contains approximately 100,000 parts per million of gluten. Under the FDA’s gluten-free labeling rules, foods making a gluten-free claim on product packaging must contain less than 20 parts per million of gluten. In this same study wheat flour fermented with sourdough lactobacilli and fungal proteases decreased the intact gluten content to under 10 parts per million.

      HOWEVER, sourdough wheat bread is not made using completely hydrolyzed wheat flour. You can not make what is typically thought of as a sourdough wheat bread product with a wheat flour that has a gluten content under 10 parts per million unless other ingredients are added to the flour to add structure. As the above-mentioned study states, “… the hydrolyzed flour is suitable for making sweet baked goods and also bread and pasta if supplemented with gluten-free structuring agents.”

      Sourdough wheat bread made in an artisanal bakery is not using hydrolyzed wheat flour to make their bread.

      November 6, 2018 at 1:59 pm
  • Deborah Scragg Reply

    You quoted that 2 participants in the study had no ill effects but that they had intestinal symptoms, you did not add that the study had 3 groups and that there were different results per group. The results of the study showed good results from hydrolysed wheat protein. Which is important for people with CS. It’s vitally important that bakers who are catering for people with gluten sensitivity are responsible, which the folks you called out clearly weren’t.
    The responsibility to paint a clear picture is also important. The third test group in the Greco study likely suffered no harm as there was only 8ppm gluten content in the bread they ate. This was achieved in a lab with sourdough and fungal proteases. This is not commercially available, true, but it’s exciting and that was my point. It was a shame it was lost in your article that is all.

    November 6, 2018 at 3:25 pm
    • Tricia Thompson Reply

      Deborah, this is not a review of the article. A link to the full article is provided. The more important point is that in the US (maybe not in the UK?) we have bakers misunderstanding this study. As a result, folks with celiac disease are eating wheat-based sourdough bread. The point of this post is to provide testing data to let consumers know that what is available commercially is not what was developed under laboratory conditions and used in this study.

      November 6, 2018 at 3:46 pm

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