Essential to the proper functioning of the human body, vitamins are accountable for maintaining a normal metabolism as well as proper cellular growth and development. Vitamins are divided into two categories: fat-soluble and water-soluble. Vitamins A, D, E, and K are the four fat-soluble vitamins with the others falling into the water-soluble category. If a vitamin is fat soluble, that means it can be stored in fat and used at a later date. Water-soluble vitamins must be used immediately (excess is expelled via urine).

Each vitamin serves a specific purpose within the human body. A deficiency in vitamins may lead to various health issues while possibly increasing your risk for conditions like heart disease, various cancers, and osteoporosis (weak bone density).

A list of vitamins:

Required to build and maintain strong bones, a fat-soluble vitamin, vitamin D aids the body in calcium absorption. Adequate amounts are rarely found occurring naturally in food.
This is a vastly important vitamin helps the body's ability to fight free radicals, vitamin E (tocopherol) also boosts the immune system and is found predominantly in vegetable oils and nuts.
Essential for creating blood clots, the best sources of the fat-soluble vitamin K are green and leafy vegetables.