Oranges is an excellent source of vitamin C. A single medium-sized orange can fulfil about 72% of your daily requirement for vitamin C. Since vitamin C plays a crucial role as an antioxidant by protecting your body against the damage caused by free radicals generated in the body. It therefore reduces inflammation in immune related conditions like rheumatoid arthritis and osteoarthritis. Although debatable, researchers suggest that vitamin C also plays an important role in strengthening immune responses of the body, protecting against recurring cold and cough or any other common infections.