Vitamins are a group of substances that are essential for normal cell function, growth, and development. There are 13 essential vitamins, meaning they are needed for the body to function. They are A, C, D, E, K, B1, B2, B3, B6, B12, Pantothenic acid, Folic acid, and Biotin .Vitamins are grouped into two categories: 4 fat-soluble vitamins A, D, E, and K which are stored in the body's fatty tissue. and 9 water-soluble vitamins. The body must use water-soluble vitamins right away. Any leftover water-soluble vitamins leave the body through the urine. Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years. Each of the vitamins has an important job in the body. A vitamin deficiency occurs when you do not eat enough fruits, vegetables, beans, lentils, whole grains and fortified dairy foods. Vitamin deficiency can cause health problems including heart disease, cancer, and poor bone health. Dietary supplements are another way to get the vitamins you need if the food you eat is not supplying enough vitamins. Supplements can be helpful during pregnancy and for special medical problems.