INS and type 2 diabetes mellitus: However, our group has demonstrated that the ingestion of insoluble cereal fibres from wheat or oat extracts and whole grain products (demonstrated as non-fermentable in vivo and in vitro [35]), and not the soluble and highly fermentable types of dietary fibre, associates with improved insulin sensitivity and risk for the development of type 2 diabetes mellitus (T2D) [36].