‘Gluten-Free’ Restaurant Dishes Sometimes Aren’t

‘Gluten-Free’ Restaurant Dishes Sometimes Aren’t

If you have celiac disease, gluten causes your body to attack itself, damaging your intestines. So it’s essential to avoid the stuff—but a new study suggests that restaurants’ “gluten-free” labels are often wrong.

The study wasn’t able to determine how trustworthy the labels are, so eating out is still a bit of a minefield—which, if you have celiac, you already know.

The data comes from a company, Nida, that sells a gluten detector. It’s expensive, at $405 for the device plus $8 for each one-use test capsule.

If you pair the device with your phone, you can choose to “share” your test results with the company. They used those shared results to try to figure out what’s in the foods people are testing.

The results: a lot of the foods came up as gluten-positive, about a third of them on average, including half of the pizza and pasta samples. Positive results were more likely at dinnertime than during other meals. Does this mean you should avoid restaurant pasta dinners? Maybe.

This study has some serious limitations, though

To be clear, these are foods that people who own a portable gluten sensor decided were suspicious enough to test. (Even a very accurate test will turn up a lot of false positives if it’s getting used a lot on gluten-free foods, so that’s important to keep in mind.)

The authors of the study also note that people may have been more likely to share their results if they were positive. Sharing the results requires the user to answer questions about the food, which I’m guessing even the dedicated users don’t do at every meal.

There’s one other caveat. The Nida device is very sensitive—possibly too sensitive. Packaged foods can be considered “gluten-free” if they contain less than 20 ppm of gluten, but Nida doesn’t report an amount of gluten found. Instead, it gives a yes-or-no answer, often flagging foods with 5 or 10 ppm of gluten. Does that make it really good, or nearly useless? It’s hard to say.


  • Be interesting even more so doing a poll on people who are gluten-free and know what gluten actually is.

    • Why? What exactly are you looking to test there? Do people with cat allergies know what histamine is? They sure know its effects, as do coeliac suffers after ingesting gluten, whether they know what it is or not.

      • No they dont.

        A majority live under the false assumption Gluten = Bad and that Gluten-free = Healthier. Gluten-free is not healthier for you.

        anteaters comment is not directed to actual coeliacs, Its addressed to the ones who arent and are just gluten free as a trendy diet not based in science.

    • Look up Fructan intolerance. My SO worked out this type of sugar messed her digestion up big time (not too different to lactose intolerance). Much happier avoiding this sugar and it turns out many grains are high in this sugar. It’s possible people avoiding wheat isn’t because of gluten but because they have Fructan intolerance.

      There’s plenty the medical world are only learning about when it comes to digestion. You’re right to approach things with cynicism (I do) but in this case I’ve witnessed the change first hand.

  • I would less rely on people with a mobile phone application device, and go with a more prudent study. The Medical Journal of Australia had two studies in 2018 on this, they used two separate lab kits to confirm their results…

    The dining out study found it was
    14 of 158 samples (9%) contained detectable gluten

    They also researched manufactured food…
    We found that 2.7% of foods labelled “gluten-free” were not compliant with the national standard of no detectable gluten

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