IPA says manufacturing process, not 'contamination,' accounts for traces of gluten researchers found in probiotics

By Hank Schultz

- Last updated on GMT

IPA says manufacturing process, not 'contamination,' accounts for traces of gluten researchers found in probiotics

Related tags Celiac disease Coeliac disease

A recent study that found traces of gluten in probiotic supplements has provoked a measured response from the International Probiotic Association. IPA executive director George Paraskevakos noted that only one product in the study that made a gluten-free claim was found to contain the protein at an unacceptably high level and that manufacturing considerations could account for the presence of gluten in others. It’s not a question of ‘contamination,’ he said.

The study, which was performed by investigators at the Celiac Disease Center at Columbia University Medical Center (CUMC) and presented at the recent Digestive Disease Week meeting in Washington, DC, tested 22 top-selling probiotics. It found some traces of gluten in 12 of them.

"Many patients with celiac disease take dietary supplements, and probiotics are particularly popular,"​ said first author Dr Samantha Nazareth from CUMC.

"We have previously reported that celiac patients who use dietary supplements have more symptoms than non-users, so we decided to test the probiotics for gluten contamination,"​ she explained.

One product fails clam

In those supplements which had gluten, the researchers found four that had more than 20 ppm, which is the level FDA sets to qualify for a gluten-free claim.  Only one of those products made a gluten free claim. 

"We know that most patients with celiac disease only develop intestinal damage when consuming more than 10 milligrams of gluten daily, and it is unlikely that contaminated probiotics can lead to that amount unless patients are ingesting mega-doses,"​ added study co-author Dr Benjamin Lebwohl. He did question, however, why gluten could be found in any of them.

“Our members adhere to GMPs which are very strict about what you allow into your plants. A product could contain gluten as a result of the standardizing agents that are used.  If a customer wants a different level of CFUs, say 10 million instead of 20 million, you would in effect ‘cut’ that with an excipient. It’s not like there are only bugs in the capsule,”​ Paraskevakos said.

In a statement about the research, the IPA said that certain growth media or excipients  “may introduce very small amounts of gluten. To control for this, certified production ingredients can be used or, if those are not available, products should be tested using accredited labs and methods to ensure levels remain below the ‘gluten-free’ labeling limit.

“Probiotic bacteria require complex growth media that contain a range of ingredients but these can be controlled for the presence of gluten and other allergens.  If a manufacturer chooses not to control for the presence of gluten, its products cannot be guaranteed as gluten-free.  It is normal practice that only products labelled as gluten-free can be expected to be gluten-free,” ​the IPA wrote.

A spokeswoman at the Celiac Disease Center said the study was blinded, and the organization would not be naming the products that were tested. The lead researcher did not respond to a request from NutraIngredients-USA for more information. Without more detail, Paraskevakos said it is impossible to take a position on whether the lone product that was labeled as gluten-free but was found to violate that claim was mislabeled or if it was a case of a manufacturing error.

“We definitely need more information, and I want to emphasize we are not trying to take a shot at these guys. We want to understand what’s happening and to work with them. Celiac disease is an important condition, and we don't know of anyone who is 'prescribing' probiotics for it. There are disclaimers on probiotic labels about people with immune compromised conditions. We think patients should consult their doctors,”​ Paraskevakos said.

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Innovation in Postbiotics and Immunity Effects

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Morinaga Milk Industry Co., Ltd. | 13-Jan-2023 | Technical / White Paper

With increased research that supports the link between human health and gut microbiome, postbiotics are an emerging supplement or ingredient that is beneficial...

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Gluten Used to Grow Cultures

Posted by Sarah,

I think it would be very helpful if probiotic manufacturers would disclose on the label if gluten sources were used to grow the cultures. I wonder if that's the reason I've had problems with several probiotic brands. One tested to 5 ppm of gluten, and another was made by a company whose multivitamin I swear by and have used for years with no problems. Even more than that, it would be wonderful if these companies would use media that are truly gluten and allergen free, although I don't know how feasible that is.

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Posted by Jeanne Reid,

As a Celiac patient with celiac children, I have to comment on the sentence "Celiac disease is an important condition, and we don't know of anyone who is 'prescribing' probiotics for it."

Many many many doctors prescribe probiotics for celiac patients. It is very common. When my 1 year old was diagnosed with celiac, the GI Specialist insisted that I put him on "adult dose" probiotics immediately. I received the same orders from my doctor. Because probiotics are available over the counter, a formal prescription isn't written.... but to a patient, the paper doesn't matter. Research and professional sources support the use of probiotics for celiac patients...



Ensuring the safety of pharmaceuticals is paramount, attempting to shift blame to the celiac patient for taking a suppliment is outrageous.

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Public Health Organization Offers Solution to Gluten in Probiotics, Dietary Supplements

Posted by NSF International,

This is why gluten free testing and certification programs are so essential. There are currently 73 dietary supplements (out of more than 600 other food products) that have been tested and certified to NSF International's Gluten Free Certification program, which verifies that products contain 20 parts per million (ppm) or less of gluten, a limit set by the U.S. FDA for foods labeled as gluten-free.

In addition to product testing, NSF International audits the manufacturing facilities to ensure the manufacturing process prevents gluten contamination of products and reviews the formulations to ensure that the ingredients used are gluten-free.

The NSF International “Certified Gluten-Free” label on dietary supplements and other food products provides an added level of assurance to consumers, especially the more than 3 million Americans with celiac disease or gluten intolerance.


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