Ascorbic acid is essential for collagen, carnitine and neurotransmitters biosynthesis. Most plants and animals synthesize ascorbic acid for their own requirement, butpes and humans can not synthesize it due to lack of an enzyme gulonolactone oxidase. 

Though ascorbic acid was discovered in 17th century, the exact role of this vitamin in human biology and health is still a mystery in view of many beneficial claims and controversies.

Many health benefits have been attributed to ascorbic acid such as antioxidant, anti-atherogenic, anti-carcinogenic, immunomodulator and prevents cold etc. However, lately the health benefits of ascorbic acid has been the subject of debate and controversies:

• The relation between ascorbic acid and cancer is still a debatable.
• There is compelling evidence for antioxidant protection of lipids by ascorbic acid both with and without iron co-supplementation.
• Current evidences suggest that ascorbic acid protects against atherogenesis by inhibiting LDL oxidation.
• The data on vitamin C and DNA damage are conflicting and inconsistent.