One of the primary nutritional benefits of oranges is their vitamin C, or ascorbic acid, content. Vitamin C keeps your skeleton healthy by helping your body make collagen, a protein that strengthens your bone tissue. It also helps maintain other collagen-rich tissues, including your blood vessels and skin. Each large orange contains 97.9 milligrams of vitamin C -- more than your entire day's required intake of the nutrient, according to the Linus Pauling Institute.