Differential interference contrast (DIC) light micrograph of ascorbic acid (vitamin C) crystals. The main dietary sources of vitamin C, which is also known as ascorbic acid, are citrus fruits and green vegetables. Vitamin C is required to maintain healthy connective tissue and heal wounds. As an antioxidant it protects the health and integrity of cells. Magnification: x25 when printed at 10 centimetres wide.