Vitamin C, An Essential Nutrients for Human
Vitamin C or L-ascorbic acid is an essential nutrient for humans, a large number of higher primate species, a small number of other mammalian species (notably guinea pigs and bats), a few species of birds, and some fish.
Ascorbate (an ion of ascorbic acid) is required for a range of essential metabolic reactions in all animals and plants. It is made internally by almost all organisms, humans being a notable exception. Deficiency in this vitamin causes scurvy in humans. It is also widely used as a food additive.
The pharmacophore of vitamin C is the ascorbate ion. In living organisms, ascorbate is an anti-oxidant, since it protects the body against oxidative stress, and is a cofactor in several vital enzymatic reactions.
Scurvy has been known since ancient times. People in many parts of the world assumed it was caused by a lack of fresh plant foods. The British Navy started giving sailors lime juice to prevent scurvy in 1795. Ascorbic acid was finally isolated by 1933 and synthesized in 1934. The uses and recommended daily intake of vitamin C are matters of on-going debate. A recent meta-analysis of 68 reliable antioxidant supplementation experiments involving a total of 232,606 individuals concluded that consuming additional ascorbate from supplements may not be as beneficial as thought. source: wikipedia