Oranges are highly valued for their vitamin C content. This wonderful fruit has more to offer nutritionally than just this one nutrient, containing sufficient amounts of folacin, calcium, potassium, thiamin, niacin and magnesium. Oranges are good source of vitamin A as well. Eating the whole fruit provides 130% of the recommended dietary allowance for vitamin C, less than the juice, but more fiber, which is not present in the juice. Vitamin C from oranges can prevent scorbutic risks. Vitamin C also builds collagen which is the main material of human tissue, helping wounds and injuries recover faster. All varieties of oranges should be firm, heavy for size, and have fine-textured skin.