Gluten-free grains can still contain gluten primarily due to two reasons: cross-contamination and the presence of similar proteins that are not safe for people with gluten intolerance.

Gluten in Grains

• Gluten is a specific protein found mainly in wheat (including varieties like spelt, kamut, and farro), barley, rye, and triticale, and it is not naturally present in grains like rice, corn, quinoa, millet, and buckwheat, which are considered gluten-free.

• Some grains have proteins similar to gluten but do not trigger the same immune response seen in people with celiac disease or gluten sensitivity. For example, rice and corn proteins are safe, but barley contains hordeins and rye contains secalins, which are gluten proteins harmful for gluten-sensitive individuals.

Reasons Gluten-Free Grains Might Contain Gluten

• Cross-Contamination: Gluten-free grains can become contaminated with gluten during harvesting, processing, or packaging if they are processed on shared equipment with gluten-containing grains or are stored and transported together.

• Mislabeling or hidden gluten: Some products labeled gluten-free may still contain gluten due to wheat starch not adequately processed to remove gluten or from ingredients derived from gluten-containing grains like malt (from barley).

Practical Advice

• Carefully read product labels and look for certification that confirms gluten-free status.
• Purchase from trusted sources that test for gluten contamination to ensure levels are below 20 parts per million (ppm), considered safe for most people with gluten sensitivities.

In summary, while certain grains are naturally gluten-free, they can contain gluten if contaminated with gluten-containing grains or when processed with gluten-containing ingredients. This makes testing and certification essential for those with gluten intolerance or celiac disease.