Controversial New US Study Suggests Coeliac Safety with Shared Fryers
Are shared fryers still considered off limits for coeliacs? A recent US-based study produced very interesting results that we need to review
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Hey Gluten Free Fam,
Coeliac safety and shared fryers remains something of a hot topic - literally and figuratively.
Any shared environment or surface that leaves coeliacs exposed to the smallest trace of gluten places individuals with the autoimmune disease at risk of damage, leading to a wide array of symptoms affecting your health.
Needless to say, a shared fryer that mixes gluten-containing ingredients with their gluten free counterpart is widely considered a recipe for disaster. For many who live with the condition, the advice is simple and straightforward: you’re better safe than sorry.
However, researchers from the United States tested French fry and tortilla chip samples, both naturally gluten free, to determine where they sit on the parts per million threshold once exposed to a shared fryer.
The results have raised serious eyebrows, created debate and left us with more questions to ponder around coeliac safety, cross-contamination, and how coeliac research is communicated.
What Did the New Study on Shared Fryers Find?
The recent study titled ‘Shared Fryers May Not Always Be as Risky for Gluten Cross-Contact in Celiac Disease as Dietary Guidance Suggests’ was published by Nutrients this month. It examined the gluten cross-contamination risk associated with shared fryers.
The multi-centre study, led by the Celiac Disease Foundation, tested 98 samples of naturally gluten-free foods prepared in fryers also used for gluten-containing foods. This included 55 orders of French fries and 43 orders of tortilla chips from food outlets across 14 states in the US.
The results made for curious reading. Of the 98 samples tested, 92 (93.9%) contained less than 20 parts per million (ppm) of gluten. However, six samples (6.1%) exceeded that level, with all six being French fries. Gluten concentrations in those samples ranged from 29.6 ppm to more than 80 ppm.
What does this mean? It suggests gluten cross-contact may vary depending on the food and the circumstances in which it’s prepared. While most samples tested below the US gluten-free threshold, the six samples that exceeded it shows contamination remains a genuine risk.
Why Were French Fries and Tortilla Chips Tested?
For the study to offer a better view about foods that fall between the grey area of gluten free but prepared in gluten-containing environments, French fries and tortilla chips fit the bill. They’re both naturally gluten free foods, but they’re commonly prepared in commercial fryers.
Coeliacs who are away from home and seeking gluten free restaurants and outlets can gravitate to fries and chips as their go-to menu option. But the way restaurants prepare them can vary, making them useful foods to investigate in a real-world study.
The results differed when comparing French fries vs. tortilla chips. All 43 tortilla chip samples contained less than 5 ppm of gluten, which was below the laboratory test's limit of quantification. In comparison, six of the 55 French fry samples exceeded 20 ppm, meaning approximately 11% of the French fry samples were above that level.
Measuring Safe vs. Unsafe with Shared Fryer Oil
A major point of conjecture is found between study participants who replaced their fryer oil daily against those who replaced it weekly. None of the 39 samples collected from establishments reporting daily oil replacement exceeded 20 ppm of gluten. By comparison, four of the 35 samples from outlets reporting weekly oil replacement exceeded that threshold.
Meghan McKeon, Senior Director of Education at the Celiac Disease Foundation, outlines the study is a very small piece of a larger picture, adding context for those wanting to know where risk lies, and how accurately it’s judged case by case.
“These findings don’t tell us that every shared fryer is safe. They tell us that the risk is not the same in every situation.”
“For people with celiac disease, dining decisions are rarely as simple as ‘safe’ or ‘unsafe,’” she said. “These findings give us better information to help patients understand and weigh risk. A gluten concentration is only one piece of the picture. We also need to consider how much someone eats, how often an exposure occurs, and how it fits into their overall gluten exposure. The goal is to give people the evidence and context they need to make informed decisions with their healthcare team.”
Megan would be a special guest on Episode 80 of the You Had Me At Eat podcast. The Senior Director spoke with the show about what the study found, its limitations, and how coeliacs should approach the information in further context.
We encourage you to give it a listen.
Coeliac Community Response to Research Findings
The swift nature of the response from the gluten free and coeliac community has been vocal, but also a point of strong debate. For many who read the headlines and see the grabs online, the response from many is simple. From their perspective, it will be read, or misconstrued for those running establishments, to relax their approach to cross-contamination and threaten investment towards dedicated gluten free fryers.
There’s already a sizeable skepticism from many with the very notion of the parts per million threshold, and the fact there’s yet to be a global consensus on that topic understandably leads coeliacs to pushback against the Foundation for running a study of this type.
For expert tips on dining out and confronting cross-contamination risk, listen to Episode 133 of A Gluten Free Podcast with special guest chef Anthony Dionne of Pasta Di Casa.
Eli, aka the_celiac_scientist on Instagram, commented on a Glass of Weinstein’s discussion on the findings to offer missing context. From his perspective, the devil is very much in the details, and this is something readers and community members should know before jumping to sweeping conclusions.
“In the discussion section of the study they stated “Importantly, the study was not designed to assess clinical outcomes, symptom provocation, or mucosal response, and the findings should not be interpreted as evidence of individual tolerance or safety”… Specifically, they did not mention when they collected samples in relation to the last oil change. Additionally, the restaurants they got samples from were informed ahead of time to use clean hands prior to collecting samples.”
Casey Cromwell, aka collegeceliackc, also offered another point of view, arguing that a shared fryer that meets strict protocols is still better than no option, especially for coeliacs who are capable of making their own personal choice based on available information.
“Here’s the important part: this study does NOT mean all shared fryers are safe for people with celiac‼️,” Cromwell posted. “Instead, the researchers hope this simply provides more info for EVERY CELIAC to make their own educated choice. 🙏 Cuz not everyone has the luxury of access to dedicated fryers. 🥺 And if the options are going hungry, eating straight-up gluten… or getting something from a shared fryer that changes its oil daily… that may be a better choice for some celiacs. 🤷♀️”
Coeliac Dietitian Nutritionist Tayler Silfverduk was taken aback by the findings. She sees the study as a positive step forward in learning more about cross-contamination risk.
“This study on gluten contamination in shared fryers SHOCKED me!!! Edit to clarify: this is not enough data to CHANGE my recommendations on shared fryers but it is going to be factored in because it exists & people may encounter it and should know about it!!! This kind of research is important in moving our understanding of gluten cross-contact risk forward!”
For Kevin G., aka The Macro Celiac, news from this study won’t change his stance one bit on shared fryer environments. For the sake of his family’s safety and health, it remains a zero tolerance policy.
“From what I can tell, what was released about this study did not paint the full picture and could do far more harm than good,” he posted. “My kids and I will be sticking with dedicated fryers only, and encourage other celiacs to do the same.”
Should Coeliacs Eat Food Cooked in Shared Fryers?
We’ll take our cue from Vanessa Weisbrod on this question, the Chief Programs Officer at the Celiac Disease Foundation and lead author of the study.
“This study is not a green light to eat from any shared fryer,” Weisbrod states. “This is about giving people better information, not taking away precautions.”
One of the study's co-authors, Dr. Edwin Liu from Children's Hospital Colorado, explained why the findings matter:
“These findings don’t tell us that every shared fryer is safe. They tell us that the risk is not the same in every situation.”
The Celiac Disease Foundation offered a more concise summary, making the case that the study is an exercise in offering people more information when making a personal judgement.
“Researchers are not recommending that people with celiac disease begin routinely eating foods prepared in shared fryers. Rather, these findings provide new evidence that patients, families, dietitians, and clinicians can use when discussing risk and making individualized decisions.”
In short, there’s no one-size-fits-all rule that applies here. As beneficial and helpful as it is to examine and review provisions around coeliac safety, and what’s deemed safe and unsafe, it’s critical that every step of the process is transparent, openly communicated and understood in context.
We do urge coeliacs to seek out dedicated gluten free fryers for all fried food when eating out. With this being said, if you’re able to learn more about the 20ppm threshold and seek out expert dietitians and specialists, and you do discover a shared fryer environment that runs rigorous oil changes with an establishment that understands coeliac-safe protocols, that might give you confidence to explore their menu options.
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