Beef kidney is a nutrient-dense secreting organ. It provides: Vitamin B12 and iron — support red blood-cell formation and oxygen transport. Selenium — supports thyroid function, immunity and antioxidant protection. B vitamins, especially B2, B3, B5 and B6 — help convert food into energy and support the nervous system. Folate — contributes to cell growth and blood formation. Protein, phosphorus, zinc and copper — support muscles, tissues and normal metabolism. Beef kidney is particularly rich in B12, selenium and riboflavin. Please keep in mind complete, raw food mixes often have kidney and other secreting organs. Use in moderation, and be aware of what percentage of secreting organs you are feeding. Whole, cubed beef Kidney. Kidneys are odd shaped organs, and therefore the cube size is not always perfect cubes. Sold by the pound. Enter how many pounds as quantity.