Vitamins are a very diverse group of nutrients divided into two types:
- Fat soluble: Vitamins A, D, E and K. These vitamins are essential to a healthy life, are required in small quantities (micrograms or less) per day, and the excess is stored in the liver and body fat.
- Water soluble: thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), pantothenic acid, folic acid, biotin, cobalamin (B12), choline, and carnitine. These vitamins are essential to a healthy life and are required in small quantities (micrograms or less) per day as well.
However, water soluble vitamins (except for B
12) are not stored in the body and therefore must be consumed daily. B
12 is stored in the liver, and it has been estimated that most healthy people, dogs, and cats have a 2-5 year supply stored in the liver.