Some rice-based foods for people with celiac disease contain relevant amounts of arsenic

ScienceDaily - Health and Medicine News

Rice is one of the few cereal grains consumed by people with celiac disease, as it does not contain gluten. However, it can have high concentrations of a toxic substance - arsenic - as revealed by the analyses of flour, cakes, bread, pasta and other foods made with rice, research shows. This is important for those suffering from celiac disease, which affects almost 1% of the population of the western world. These people cannot tolerate gluten and are thus obliged to consume products without it, such as rice.