The major vitamin found in citrus fruit is Vitamin C. Citrus fruits like oranges, lemons, limes, grapefruit, and tangerines are an excellent source of Vitamin C, which is essential for healthy skin, bones, and connective tissues. Vitamin C is also an antioxidant that helps protect the body from harmful free radicals and plays a role in the absorption of iron from plant-based foods. A deficiency of Vitamin C can lead to scurvy, a disease characterized by weakness, anemia, and gum disease.