100% Beef Kidney - That's it, nothing else, nothing added! Kidney contains B12, riboflavin (B2), and iron, as well as healthy amounts of B6, folate, and niacin. Riboflavin is required for the proper development of many things in the body including the skin, lining of the digestive tract, blood cells, and brain function. Organs offer some of the densest sources of nutrients like B vitamins, iron, phosphorus, copper and magnesium and are rich with the most important fat-soluble vitamins!