ist in reis gluten enthalten — what are common causes?

The provided context does not contain specific data on rice and gluten. Generally, rice is naturally gluten-free. Common causes of gluten in rice include cross-contamination during processing (e.g., in mills that also handle wheat), added spices or sauces containing gluten, and processed rice products like rice noodles or rice balls that may contain wheat flour. Individuals with celiac disease or gluten sensitivity should look for certified gluten-free rice products. The evidence for this is based on general nutritional knowledge, not on the provided sources.