Vitamin C, or Ascorbic Acid, is an essential, water-soluble vitamin that can be found in many fruits and vegetables, including oranges, strawberries, kale, and spinach. One of the core reasons people choose to supplement with Vitamin C is due to its purported benefits on immune functioning, antioxidant support and health. Vitamin C has been shown to promote the production of white blood cells, which help protect the body against infection.