Vitamin C. Computer graphic depicting a molecule of vitamin C (ascorbic acid). The molecular formula is C6.H8.O6. Atoms are shown as spheres, joined by atomic bonds. Atoms are colour-coded: carbon (green), oxygen (red), hydrogen (white). Vitamin C is a water soluble vitamin which plays an essential role in the activity of many enzymes in the human body. It is necessary for the growth and maintenance of healthy bones, gums, teeth, ligaments, and blood vessels. It is also thought to stimulate the immune system against infection. Dietary sources of vitamin C are citrus fruits and green vegetables. Deficiency of vitamin C leads to scurvy, with swollen bleeding gums and anaemia.