Vitamins are essential for healthy systems function. Because we do not make vitamins within the body, we must ingest them from food or take in an extracted form. There are two categories of vitamins: fat-soluble and water-soluble. Vitamins benefit the body in a number of ways. For example, vitamin A or retinol benefits eyesight, among other things. As will be discussed, vitamins aid in cardiovascular health, immune function, and optimize physical fitness.