As far as citrus fruits go, oranges are the best. They deliver almost every vitamin and mineral out there, and they're easy to eat (or drink). Their biggest selling point is the huge amounts of vitamin C they contain. This nutrient boosts immunity and helps your body absorb iron. But it does even more: Vitamin C prevents cell damage that opens the door for cancer development.
Citrus fruits also deliver a fair amount of fiber, which helps regulate digestion. The pectin fiber in grapefruit lowers LDL (bad) blood cholesterol. When picking grapefruit, darker is better. Red grapefruits have more of the antioxidants beta carotene and lycopene than pink or white grapefruits.
Speaking of antioxidants, citrus is loaded with those and flavonoids, which are phytochemicals in the polyphenol class. Phytochemicals protect cells from the damage of free radicals, block cancer-causing substances, protect against heart disease, and promote healthy eyes and vision.