Vitamin C. Computer model of a molecule of the water-soluble vitamin C (ascorbic acid, C6.H8.O6). The atoms (solid tubes) of this organic molecule are colour-coded: carbon (yellow), hydrogen (grey) and oxygen (red). Vitamin C is obtained from fresh fruit, especially the citrus fruits such as lemons and oranges. It must be regularly replenished. It is required to maintain healthy connective tissue and heal wounds. It is also an antioxidant that may protect against viruses and cancer-causing substances. Lack of vitamin C causes scurvy, with symptoms such as bleeding gums, loose teeth and open skin sores. Small amounts of vitamins are an essential part of a healthy diet.