Does wheat starch belong in a gluten-free diet?

Does wheat starch belong in a gluten-free diet?

Please also see the post Wheat Starch in Gluten-Free Foods in 2023: An Update from Gluten Free Watchdog available at

In Honor of Celiac Disease Awareness Month, Gluten Free Watchdog is writing a series of articles (the goal is one per day during the month of May) related to the gluten-free diet–currently the ONLY treatment for celiac disease. 

Post (#8)…

First some background…

Under the FDA’s gluten-free labeling rule wheat starch is allowed in gluten-free foods as long as the final product contains less than 20 ppm of gluten. This is because wheat starch is considered by the FDA to be an ingredient processed to remove gluten.

Wheat starch is not wheat grain and it is not wheat protein. It is not intended to contain any gluten. BUT it is very difficult to completely separate the starch and protein components of wheat so small amounts of gluten remain in the wheat starch. Not all wheat starch is created equal. Depending on the extent of processing wheat starch will contain varying amounts of residual gluten. A recent study found wheat starch to contain from < 5 ppm of gluten to over 10,000 ppm of gluten (1). (wheat starch and wheat gluten are separated using water by first making dough). 

Should folks with celiac disease eat wheat starch?

I have been writing about wheat starch since 2001 and the publication, “Wheat starch, gliadin, and the gluten-free diet.” My opinions are constantly evolving based on new information. In 2008 I wrote the following on wheat starch (from the Gluten Free Nutrition Guide, McGraw Hill):

“… If a manufacturer of wheat starch or products containing wheat starch demonstrates through testing that its products contain less than 20 parts per million of gluten, then in theory I support their consumption by people with celiac disease.”

BUT more is known today about testing wheat starch for gluten than was known 10 years ago.

For example, according to R-biopharm, wheat starch should be tested for gluten using a competitive ELISA (2) in addition to a sandwich ELISA. During the processing of wheat starch, residual gluten may be partially broken down (1). A sandwich ELISA detects intact or relatively intact gluten protein. A competitive ELISA detects gluten that has been broken down into smaller protein fragments.

In addition, the gluten content in wheat starch may be underestimated. The reason for this is complex. In brief, gluten is made up of prolamins and glutelins; in wheat the prolamin is gliadin and the glutelin is glutenin. When using the R5 ELISA, the gliadin value is multiplied by 2 to determine the level of gluten. In general, the gliadin to glutenin ratio is considered to be 1:1. However, in reality, this ratio is variable. In one recent study the ratio varied from 0.31 to 3.19 in wheat starch samples (1). The ratio was less than 1 in seven out of fifteen wheat starch samples (meaning that the gluten content was underestimated) (1).

Researchers concluded, “The considerable variation of gliadin to glutenin ratios confirmed the need for a reliable, non-immunochemical analytical method capable of accurately quantitating both gliadin and gluten in wheat starch samples to ensure the safety of gluten-free foods for coeliac disease patients.” (1)

Updated opinion on wheat starch…

Because of the current limitations associated with testing wheat starch for gluten, it is the opinion of Gluten Free Watchdog that products containing wheat starch are best avoided by individuals with celiac disease.

That said, if you have celiac disease or another gluten-related disorder and you would like to eat wheat-starch based foods, it is the recommendation of Gluten Free Watchdog that you do the following:

  1. Eat foods containing wheat starch only if the product is labeled gluten-free.
  2. Establish with the manufacturer that the final product is tested using both a sandwich and competitive ELISA.

Note: At Gluten Free Watchdog we have tested wheat starch labeled gluten-free and wheat starch not labeled gluten-free. As was expected, wheat starch not labeled gluten-free contained higher levels of gluten and gluten fragments than wheat starch labeled gluten-free. Nonetheless, wheat starch labeled gluten-free contained small levels of both intact and hydrolyzed gluten.

Note: While wheat starch is used in gluten-free foods in Europe, it is used in very few products in the US. The most well known product is likely Schar brand croissants. Schar provided Gluten Free Watchdog with a statement about their testing protocol for this product

Tomorrow’s post: Happy wheat starch isn’t used in more gluten-free foods? You may have Ener-G Foods & Elaine Hartsook to thank


  1. Proceedings of the 27thMeeting Working Group on Prolamin Analysis and Toxicity. Analytical Research Reports. Katharina Konitzer, Herbert Wieser, Peter Koehler. German Research Centre for Food Chemistry, Leibniz Institute, Freising, Germany. Quantitation of gluten in wheat starch by gel permeation chromatography with fluorescence detection Available at:
  2. R-biopharm. Ridascreen Gliadin Competitive. Available at:

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Comments (19)

  • Naomi Reply

    What about Molino- Gluten free mix bread with wheat starch?

    November 18, 2019 at 8:27 pm
    • Tricia Thompson Reply

      If you are referring to the Molino Caputo wheat starch-based flour, the same information applies. Do you have a product link?

      November 19, 2019 at 1:44 pm
      • Megan Chusid Reply

        Curious about the information about Molino Caputo and it is so good. Here is the link:


        May 21, 2020 at 2:59 am
        • Tricia Thompson Reply

          Megan,Do you have a link to the wheat starch-based version? I am no longer able to find it. Which version of this product are you using–wheat starch or naturally gluten-free?

          May 28, 2020 at 2:11 pm
      • Susan Wong Reply

        Thank you for clarification. Some rice based products contains wheat starch. This is very helpful.

        October 4, 2021 at 3:19 am
  • Steve P Reply

    Hi Tricia. What do you think of the Caputo Fioreglut Italian Gluten Free Flour which has become so famous as the world’s best pizza dough flour? As a Coeliac, I waited years for a dough that mimicked the real thing and I and millions of others found it with this famous Italian brand. It does have the Italian Gluten Free certification and government seal, but apparently uses Wheat Starch. Is it safe for Ceolaics to consume?


    August 8, 2020 at 5:54 pm
  • Steve Reply

    Thank you, Tricia, for your valuable time and your kind reply. It was this wonderful article of yours that got me to contact you. The problem is that Caputo is a huge company and their claim (not made by themselves) is less than 4 parts per million of gluten. They also have Italy’s Ministery of Food standards Gluten Free symbol. They also have a huge following of this product that gives them legitimacy and credibility amongst Celiacs worldwide. I found that if I eat enough of this product I seem to get some mild allergic symptoms. I wonder how can this be with the Gluten-Free symbol and the brand’s credibility? I cannot see cross-contamination. UNLESS celiacs are also allergic to the wheat itself and there is enough of it in the starch to cause problems. I wonder if the USDA tests any of the products from Europe that enter the USA MArket for their claims? Indeed, the “GLUTEN FREE” badge on any product should never be misleading or an untested estimation. Millions of people’s health is at stake.

    Any thoughts you have are appreciated.

    August 15, 2020 at 1:12 am
    • Tricia Thompson Reply

      This product is regulated by the FDA. If they receive enough illness complaints from consumers, then they may test the product. We’ve tested this product and it tested gluten-free. That said, I’m not a fan of the use of wheat starch by folks with celiac disease. In my opinion, there is too much uncertainty with testing. I will be writing more about this issue soon.

      August 17, 2020 at 4:01 pm
      • Steve Reply

        Thanks, again, Tricia for taking the time to reply. It’s nice to know you have personally tested this Caputo Fioreglut Gluten Free flour as indeed it seems to offer so much hope to celiacs. It is thought by many globally to be the closest thing to wheat-based pizza and bread dough anywhere. I have waited for this product for 25 years and was delighted when I first made and ate it (in a 1000 degree Napoli pizza oven, it is hard to tell it from the “real” wheat product). Because it is so well-known, and the maker Caputo Italy so famous (The Coca-Cola of European Flour makers), it was given instant credibility and little vetting by the consumer public. I, personally, was shocked when I saw “Wheat Starch” as the key ingredient and realize this is the reason why it tastes and reacts so much like the “real thing.” It is nice to know this products despite the wheat starch is well below the 20ppm and thus trult Gluten Free. The WHEAT aspect is another matter, as many celiacs also are wheat intolerant (which should have a warning label not to cause confusion). Again, thank you for kindly taking the time to reply to me. Your readers are greatly appreciative of your efforts including thousands of Celiacs who are constantly looking for product and ingredient information. Many blessings.

        August 17, 2020 at 8:22 pm
      • Mary Como Reply

        Hi Tricia,
        During the pandemic, I managed to create many tasty baked good from the Caputo Fioreglut Italian Gluten Free Flour, so good in fact, many of my gluten free friends are asking me to bake more for them. Firstly, If I were to sell this product, in your opinion, is it safe to say this product is Gluten Free? Secondly, should I include in the label “contains: wheat starch” not recommened for celiacs who are wheat intolerant. Please let me know, I dont warn to harm any of my friends, Thank you in advance for your insight and knowledge.

        August 22, 2020 at 12:57 pm
        • Tricia Thompson Reply

          Hi Mary. The Caputo product is labeled gluten-free and according to the ingredients list contains gluten-free wheat starch. Wheat starch is an allowed ingredient in foods labeled gluten-free in the US. However, many folks with celiac disease in the US avoid wheat starch. You should check the cottage food laws in your state for labeling requirements. Regardless, it seems to prudent to include a full listing of ingredients (and sub-ingredients).

          August 25, 2020 at 12:57 pm
          • Mary Como

            Thanks for the great advice, I will definitely include a full listing of ingredients and sub-ingredients. Also, I am a new subscriber and just want to say THANKS! Gluten Free Watchdog is very informative and educational.

            August 25, 2020 at 1:06 pm
  • Kirsten Legner Reply

    Thanks for the informative post. Just wanted to let you know some of the links in the article seems to be broken. Perhaps it’s just me, but in case something has truly changed, I wanted to mention what I was seeing.

    April 29, 2021 at 1:51 pm
  • Madelyn Reply

    Thank you for your continued research on this! I’m interested to know if you know where one can find and purchase certified gluten-free wheat starch in the US? I’ve been searching online and have only found EU suppliers who exclusively deal in bulk (25+ kilo bags).

    September 10, 2021 at 10:12 pm
    • Tricia Thompson Reply

      I am not aware of a certified gluten-free wheat starch in the US. If anyone knows of one, please post!

      September 13, 2021 at 7:16 pm
  • Eugenia Reply

    As someone with refractory celiac disease, I wouldn’t put wheat starch in my mouth. The truth is, it’s not just gluten that makes most people with IBS, or celiac, or whatever else gut problem patients sick. Gluten might have 90% of the blame, but there are other proteins that make people sick: e.g. oats’ avenin. Even red quinoa can induce symptoms to celiac patients (while the normal white quinoa does not), according to research a few years ago.

    So, yeah… I wouldn’t put this ultra-processed thing in my mouth.

    December 11, 2022 at 8:30 am
    • Tricia Thompson Reply

      Can you please provide a reference for the quinoa study you cite? Are you referring to this study: Variable activation of immune response by quinoa prolamins in celiac disease. Am J Clin Nutr. Published ahead of print July 3, 2012?

      December 20, 2022 at 1:04 pm

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