Commonly known as ascorbic acid, this vitamin is water soluble, well known and extremely versatile.
Despite being well known as the vitamin which prevents scurvy, the precise chemical function of vitamin C is, as yet unknown. However, is is a very useful antioxidant. It also plays a part in the uptake of iron, contributes to the formation of bones, teeth, nails, hair and skin, and increases the speed at which wounds heal. The elasticity of the skin is maintained by vitamin C, which also regulates the production of stress hormones and guards against infections. In general, vitamin C helps maintain the everyday health, well being and appearance of a human body. Vitamin C tablets are often taken by people who feel "under the weather", or have a cold.
Humans, like apes, guinea pigs, bats and some fish are among the only creatures which are unable to synthesize vitamin C and therefore require it in their diet. Most animals can synthesize vitamin C from glucose; they have very similar structures. Contrary to popular belief, citrus fruits are not the best source of vitamin C, providing 'only' 50mg/100g. Kiwi fruits, rose hips, broccoli, cauliflower and green mango all contain more than 100mg vitamin C per 100g of fruit flesh. Spanish peppers contain five times as much vitamin C as citrus fruits. Vitamin C can also be found in berries and potatoes. However, it is very easily destroyed by storage or cooking, since it is sensitive to heat, light and other chemicals.
The RDA for adults is 60mg; quite high, but to be expected because of its many functions. Vitamin C can be stored in the body for several months. 10mg per day can cure and prevent scurvy, but does not allow the build up of stores. If the RDA is consumed for 2-3 months, enough vitamin C builds up to protect against scurvy for 3 months upon exclusion from the diet.
The loss of vitamin C from the diet causes scurvy after a sufficient time period to exhaust all store in the body. This disease has been known since the 15th century when it was reported in diaries of wealthy explorers such as the Portuguese, Vasco da Gama. It was mainly a disease which was rife on long sea voyages, and before this time, sailing trips tended to be short, since the technology to build large sea vessels did not yet exist. In late centuries, the British Navy lost more men to scurvy than through enemy action. The first reliable research for treatment was carried out by James Lind in 1746, but it was not until 50 years later that his research was accepted, and citrus fruits were made a compulsory part of a sailor's diet. Nowadays, those most at risk of a vitamin C deficiency are the Scandinavians. Up to 20% of the population suffer from vitamin C deficiency in the spring, since fresh fruit and potatoes cannot be grown or imported easily because of the cold climate. New supplies arrive in spring just in time to prevent scurvy. The risk of vitamin C deficiencies is also higher for smokers, slimmers and the elderly. Higher amounts may be required by people in cold environments, or people taking the contraceptive pill. Smokers tend to have 20-40% less vitamin C in their blood plasma, than non smokers of the same age and background.