This list is not exhaustive, and individual products vary. Always read ingredient labels, look for certified gluten-free verification, and work with your gastroenterologist and dietitian to establish safe practices for your individual situation.
After someone with celiac disease has eliminated obvious gluten sources — bread, pasta, pastries, beer — the exposures that remain are often the ones they didn't know to look for. These are the ingredients and products worth knowing about specifically because they frequently aren't intuitive.
Soy Sauce
Conventional soy sauce is brewed with wheat — it's typically the second ingredient on the label, right after soybeans. This surprises people because soy sauce doesn't taste like bread, and the wheat connection isn't obvious from the name. The safe substitutes: certified gluten-free tamari (read the label carefully — look for a GF certification mark, since some tamari brands use "less wheat" rather than no wheat) and coconut aminos, which are made from coconut sap and contain no wheat or soy. Both work as 1:1 substitutes in stir fries, marinades, and dipping sauces.
Malt Vinegar and Malt Products
Malt is derived from barley — which makes malt vinegar, malt extract, malt syrup, malted milk, and most conventional beers off-limits for celiac. Malt vinegar is a common component in condiments, salad dressings, and chips (particularly British-style salt-and-vinegar varieties). The safe vinegar alternatives: apple cider vinegar, white wine vinegar, red wine vinegar, and rice wine vinegar are all naturally gluten-free (verify the label for facility cross-contamination on packaged versions).
Modified Food Starch
Modified food starch is a common thickening and stabilizing agent in processed foods. It can be derived from corn, potato, tapioca, or wheat — and the label is not required to specify the source unless wheat is the origin (in which case "wheat" must appear in the allergen statement). If a product contains "modified food starch" without a wheat declaration and carries a certified GF label, it's been verified safe. Without the GF certification, the source is uncertain.
Brewer's Yeast
Brewer's yeast is a byproduct of beer brewing and is typically derived from barley. It appears in some nutritional supplements, protein powders, and savory seasonings (nutritional yeast is different — nutritional yeast is generally safe for celiac, though the GF certification on the package should still be verified). Brewer's yeast in supplements or fortified foods is a less obvious gluten source that's worth scanning for on labels.
Imitation Crab and Processed Seafood
Imitation crab (surimi) is typically made from white fish with wheat starch as a binder. It appears in California rolls, crab rangoon, seafood salads, and anywhere "crab" is listed as an ingredient on a very affordable menu. Real crab — including canned crab — is naturally GF; imitation crab frequently is not. Always verify when crab is listed as an ingredient in a restaurant dish or packaged food.
Some Medications, Supplements, and Personal Care Products
Pharmaceutical fillers and binders can be derived from wheat starch. Most medications in the United States are gluten-free, but not all — and manufacturers are not required to disclose gluten content on drug labeling. If you take a daily medication and have concerns, the pharmacist or the manufacturer's medical affairs department can usually confirm the formulation. Communion wafers are traditionally made from wheat and are a significant concern for practicing Catholics with celiac — gluten-free communion wafers are available and approved by the Catholic Church for use by those with celiac disease. Some lip products (particularly lipstick and lip balm) and toothpastes contain wheat germ oil or wheat-derived ingredients; the oral exposure risk from lip products is debated, but individuals with severe celiac may choose to avoid them.
Certain Oats and Grain Products
As noted in the celiac overview, conventional oats are a significant cross-contamination risk even though oats themselves don't contain gluten. The same applies to other grains that are processed in shared facilities with wheat — buckwheat, millet, quinoa, and amaranth are all naturally GF, but without certified GF verification on the package, facility contamination is a real possibility. The solution isn't to avoid these grains — it's to buy certified versions, which are widely available.