To the best of scientific knowledge, all animals and plants synthesize their own vitamin C, except for a small number of animals, including guinea pigs, humans, apes, the red-vented bulbul, a fruit eating bat and a species of trout, that cannot.
Two forms of vitamin C occur in nature: ascorbic acid (the reduced form), and dehydroascorbic acid (the oxidized form). Although most of the vitamin C exists as ascorbic acid, both forms appear to be utilized similarly by the human.
Vitamin C is readily and rapidly absorbed from the upper part of the small intestine into the circulatory system. Thence, it is taken unevenly by the tissues; the adrenal gland and the retina of the eye contain an especially high concentration of vitamin C, but the liver, spleen, intestine, bone marrow, pancreas, thymus, pituitary and kidney also contain appreciable amounts.
Vitamin C is also critical to immune function, the manufacture of certain nerve transmitting substance and hormones and the absorption and utilization of other nutritional factors.
In 1974, Cameron and Pauling suggested that vitamin C might play a role in the supportive care of cancer patients. Vitamin C may protect against carcinogens such as nitrosamine. This chemical is formed in the body from nitrates and nitrites found in processed meat products such as lunch meats and hot dogs.
Vitamin C is an efficient water soluble one electron reducing agent that would be predicted to have efficacy in preventing oxidative DNA damage.
The stability of vitamin C is of main concern because this is the most labile vitamin in foods. Its main loss during processing and storage is from oxidation, which is accelerated by light, oxygen heat, increased pH, high moisture content and the present of copper or ferrous salts.
Vitamin C: Essential micronutrient
