Hidden Gluten in Food

Common hidden sources include malt (malt vinegar, malt extract, malt flavoring), brewer's yeast, seitan, hydrolyzed wheat protein, and some soy sauces. Any ingredient listing wheat, barley, rye, or triticale — or their derivatives — should be treated as unsafe unless the product is labeled gluten-free.

No. Wheat-free products can still contain barley (including malt) or rye, both of which contain gluten. Always look for an explicit "gluten-free" claim certified to under 20 ppm.

Maltodextrin sold in the US is almost always gluten-free — it is typically made from corn, rice, or potato, and even wheat-derived maltodextrin is processed below detection limits. Outside the US, confirm with a gluten-free label to be safe.

Usually yes. In the US, any wheat used in natural flavors must be disclosed on the label under FALCPA. Barley and rye are not required disclosures, so celiacs should still verify with a gluten-free claim when in doubt.

Oats are naturally gluten-free but are frequently cross-contaminated with wheat during growing and milling. Only buy oats labeled "certified gluten-free" — standard oats are not safe for celiacs.