Coeliac disease turns grocery shopping into a research project. A label that looks safe at a glance can still carry wheat, barley, or rye tucked inside an ingredient most shoppers have never heard of. As a dietitian, the question I get asked most by newly diagnosed clients isn’t "what can I never eat again" — it’s "how do I actually read this label with confidence." Here’s the checklist I walk clients through.
What "Gluten-Free" Legally Means on a US Label
In the United States, a product can only carry a "gluten-free" claim if it contains fewer than 20 parts per million (ppm) of gluten — a threshold set by the FDA. That number isn’t zero, and it isn’t arbitrary: it reflects the lowest level reliably detectable by standard laboratory testing, and current understanding is generally reassuring that most people with coeliac disease tolerate trace exposure below it without ongoing intestinal damage. What the claim does not mean is that the product was made in a dedicated gluten-free facility, or that cross-contact during manufacturing is impossible. The label reflects a legal threshold, not a guarantee of a gluten-free kitchen.
Practically, this means the absence of a "gluten-free" claim on a product doesn’t automatically mean it contains gluten — plenty of naturally gluten-free foods (a bag of rice, a can of black beans) simply never bother to say so. The claim mostly matters, and mostly becomes necessary to check for, once a product’s ingredient list makes its gluten content ambiguous.
The Words That Actually Signal Wheat, Barley, or Rye
Most hidden gluten doesn’t show up as the word "wheat." It shows up as a processing term or a derivative that most shoppers skim past. The terms worth training your eye to catch:
- Malt, malt flavoring, malt vinegar, malt extract — almost always derived from barley.
- Brewer’s yeast — a byproduct of the beer-brewing process, typically barley-based.
- Hydrolyzed wheat protein, wheat starch, wheat protein isolate — explicit, but easy to miss buried in a long ingredient block.
- Modified food starch, dextrin, maltodextrin — usually corn-derived in the US and generally safe, but occasionally wheat-derived; when the source grain isn’t named and the product carries no gluten-free claim, it’s worth a call to the manufacturer.
- Hydrolyzed vegetable protein, soy sauce, natural flavors — broad ingredient categories that can legally include a wheat-derived component without naming it directly.
- Oats — naturally gluten-free as a grain, but overwhelmingly grown, transported, and milled alongside wheat. Treat plain "oats" as a cross-contact risk unless the package specifically states gluten-free oats.
- Latin or scientific ingredient names occasionally seen on specialty or imported products: Triticum vulgare (wheat), Hordeum vulgare (barley), and Secale cereale (rye) are worth recognizing even outside the grocery aisle.
None of these terms automatically means a product is unsafe — each one is simply a prompt to check further rather than assume.
Why the Allergen "Contains" Statement Isn’t Enough on Its Own
The Food Allergen Labeling and Consumer Protection Act (FALCPA) requires US packaged foods to clearly disclose major food allergens, either in parentheses next to the ingredient or in a "Contains" statement beneath the ingredient list. The original FALCPA list covered eight allergens — milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans — and sesame was added as a ninth major allergen as of January 1, 2023.
Wheat is on that list, which is genuinely useful, since US labels can’t legally omit wheat from a "Contains" statement when it’s present. But this is where the checklist matters most for coeliac shoppers specifically: barley and rye are not major allergens under FALCPA, so neither is ever required to appear in a "Contains" statement. A product built around malt syrup or barley malt extract can legitimately skip "Contains Wheat" entirely, because it doesn’t contain wheat. Relying on the allergen statement alone, without also scanning the ingredient list itself, is the single most common gap I see clients fall into soon after diagnosis.
A Practical Reading Order for the Label
When a product doesn’t carry a certified gluten-free seal, this reading order catches the most hidden risk for the least time spent per item:
- Check the "Contains" statement first for wheat — it’s the fastest disqualifier when present.
- Scan the full ingredient list for malt, brewer’s yeast, and the wheat-derivative terms above, since barley and rye won’t be flagged in the allergen statement.
- Look for "may contain" or "produced in a facility that also processes wheat" advisory language. These statements are voluntary and not legally standardized, so manufacturers use them inconsistently — some cautious brands add them even with rigorous segregation, while others omit them despite real shared-line risk. Treat an advisory statement as a flag to weigh against personal risk tolerance, not a definitive verdict either way.
- If the ingredient list is genuinely ambiguous — a generic "natural flavors" or "modified starch" with no source grain named, and no gluten-free claim on the package — contact the manufacturer directly. Most maintain a dedicated allergen line or web page for exactly this question.
The Bottom Line
Reading for hidden gluten is a skill, not a memorized list — ingredient names change, formulations get reworked, and "natural flavors" genuinely can mean different things from one product to the next. The FDA’s 20 ppm threshold gives a certified gluten-free claim a real, testable standard to meet. But because barley and rye sit outside FALCPA’s major-allergen requirements, the ingredient list — not just the allergen statement — has to be the habit. For anyone newly navigating coeliac disease, that one adjustment to how a label gets scanned does more for day-to-day safety than memorizing any single food to avoid.