Enriched flour is flour with specific nutrients returned to it that have been lost while being prepared. These restored nutrients include iron and B vitamins (folic acid, riboflavin, niacin, and thiamine). Calcium may also be supplemented. The purpose of enriching flour is to replenish the nutrients in the flour to match the nutritional status of the unrefined product. This differentiates enrichment from fortification, which is the process of introducing new nutrients to a food.