According to the Office of Dietary Supplements, Vitamin C is an essential vitamin for humans. It is a water-soluble vitamin and must be consumed regularly because it is not stored in the body. Vitamin C is needed for normal growth and development and for the synthesis of collagen, a protein found in skin, tendons and ligaments. Vitamin C is also an important antioxidant protecting cells from free radical damage. As an antioxidant, vitamin C may help protect against cardiovascular disease and cancer.