20 Surprising Sources of Gluten

When you’re newly diagnosed with celiac disease, it can be very overwhelming to learn about all of the things that can potentially contain gluten. We know the big things to watch out for are wheat, barley, and rye. But did you know that those ingredients can be used as fillers, binders, and thickeners in lots of pre-made foods that you would least expect them to be in?

I know it’s frustrating, but it gets easier with time and patience. You will quickly learn to read labels and ask the right questions about the foods you are buying. There are quite a few foods that I had no idea were a hidden source of gluten until after I was diagnosed, so I put together a pretty comprehensive list of things for you watch out for.

20 Surprising Sources of Gluten

Some of the most common ->

  • OATS – Oats are technically a gluten-free grain, but you have to be careful when you are buying them because oats are often grown on farms with wheat, as well as come into contact with wheat products during processing. Always look for the ‘certified GF’ oats.
  • SOY SAUCE – Traditional soy sauce is fermented with wheat, so this is definitely a no-go. But you can get GF tamari, which is also soy, but it is not fermented with wheat. And coconut aminos are a great soy sauce alternative.
  • SPECIALTY COFFEE DRINKS – Most people are actually surprised by this one because you don’t think about your coffee having gluten in it. But if you are getting a specialty coffee drink at Starbucks, then watch out for some of the flavored syrups, they are often wheat based. Always double check with the barista when ordering, and try to stick with a simple coffee order. If you want to make it even easier on yourself, make your own latte before leaving the house.
  • PICKLES – Check the label when you are buying pickles because they are often brined in a base of malt vinegar (which is a barley derivative). Not all pickles contain malt vinegar, but you do need to double check the label. I love Bubbie’s brand pickles.

Sauces & Salad Dressings ->

  • SALAD DRESSINGS – Whether you are buying bottled salad dressing at the grocery store, or using the salad dressing at a restaurant or salad bar, you have to be cautious. Salad dressings can often contain wheat based thickeners or even soy sauce. It will always be safer to go with a simple oil and vinegar when building your salad.
  • PRE-MADE SAUCES – Everything from barbecue sauce, pasta sauce, Asian peanut sauce, and teriyaki sauce can potentially contain gluten. Sauces are thickened with wheat products, so you have to read the label. There are a lot of brands that are creating gluten-free sauces these days, so it is becoming easier to find good substitutes.
  • GRAVY – Traditional gravy recipes are made with a roux, which is butter and flour whisked together. This helps the gravy to become nice and thick, so you will have to watch out for gravy at meal times. You can easily swap out GF flour to thicken it, though.
  • WORCESTERSHIRE SAUCE – The sauce that you most often see in steak houses is made with soy sauce and malt vinegar, so this is a definite NO.

Prepared Foods ->

  • FRENCH FRIES – You may be thinking that this sounds crazy because french fries are just fried potatoes. But, if those fries get dunked in the same fryer as the breaded chicken at your favorite restaurant, then you are going to end up with a lot of cross contamination. Always ask if they are made in a shared fryer, and if they are, you’re going to have to pass on those. You can easily make them at home too!
  • MARINATED OR PRE-SEASONED MEATS – Many marinades contain soy sauce, thickeners, or Worcestershire sauce. Always check the label to make sure it is ‘certified GF’, if not, then just make your own marinade.
  • PRE-MADE SOUPS – Pretty much any ‘cream of…’ type of soup is going to have quite a bit of flour in it. You also need to be careful at salad bars and restaurants, the soups often have thickeners.
  • IMITATION CRAB – Some of your favorite sushi rolls probably contain imitation crab, which is made of a combination of Alaskan pollock and wheat binder. Stick to the real crab meat, or the fish that isn’t pre-marinated.
  • HOTEL EGGS/OMELETS – This goes for restaurants as well, but you have to ask the waiter if the eggs and omelets are gluten free. This would normally seem like a crazy question to some people, but hotels and restaurants are known to put a little bit of pancake batter into their egg mixture to make them extra fluffy. MIND. BLOWN.
  • PROCESSED MEATS – Hot dogs can contain wheat as a filler or binder, so always read the label and look for the ‘all beef’ if possible. Also, deli meats are regulated by the USDA, not the FDA, which has a different standard for regulating gluten. You have to be careful of this.
  • BROWN RICE SYRUP – This can be found in many types of snack bars, and store bought sweetened foods in general. But the enzymes used to break down the rice can often be derived from barley.
  • BEER – Traditional beer is derived from barley, but there are several different gluten-free beer companies on the market these days.
  • LICORICE – I don’t know many people that love licorice, but if you do, watch out for this one. Wheat flour is used to bind all the ingredients and give the licorice its signature stretchy texture.
  • SEITAN – This is a very common vegan meat substitute, but not for people with celiac disease. It is made from hydrolyzed wheat protein, as many other vegan meat substitutes are as well, so always check the label if you are vegetarian.
  • SPICE MIXES/CURRY POWDER – Make sure that you are reading the label on all of your spices, and maybe even do some research into the company. Some companies lace their spice mixes with flour or other starches, and can contain trace amounts of wheat.
  • VITAMINS/SUPPLEMENTS – I know this is technically not a food product, but I wanted to include it on the list. The supplement industry is highly unregulated, so you need to do your research on the specific companies to make sure they are using third-party testing. Gluten can be found in many different supplements, so be cautious.

I hope this list helps you stay aware of the things that gluten can be hiding in. Remember to always read labels, and if in doubt, just make it at home! I have lots of recipes that can take the place of many store bought items.

*Disclaimer: this post is not meant to be medical advice. It is just a resource to help you better understand how to dine out safely with celiac disease. Always talk to your doctor about any personal medical concerns you may have.


  1. I’ve been diagnosed with Celiac for over 15 years and knew just about all of these sneaky gluten additives but the omelette “lacing” is mind blowing! Thank you for laying this out for everyone and with such clarity!

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