Vitamin C is a water-soluble, antioxidant vitamin required for tissue growth and repair. It is not created by the body, and, due to its water-soluble nature, it is not preserved by the human body, meaning the body's supply of this vitamin (40mg a day for adults) must be constantly replenished. Vitamin C is vital to the formation of the neurotransmitter norepinephrine, as well as collagen, a protein that has many uses in the body. As such, it vitamin C is important in healing wounds, repairing and maintaining capillaries, bones, and teeth.
Because vitamin C is an antioxidant, it can block some damaged caused by free radicals created as by-products during the digestion of food. A build up of free radicals can cause or contribute to a larger variety of medical problems, such as arthritis, cancer, and heart disease.
Consuming too much vitamin C is rare, due to the body's inability to store it and build up an excess. A large quantity of vitamin C consumed in a short period of time is the only way to achieve vitamin C toxicity, which can lead to stomach pains and diarrhea, but these symptoms will stop with the decrease in vitamin C consumption. It is difficult to create vitamin C toxicity without the use of vitamin supplements, and, since the body does not store vitamin C, the effects of toxicity are temporary.
More common is the deficiency of vitamin C, which, when severe, can lead to scurvy. This is still a rare condition in developed countries, since one fourth of the suggested daily allotment, 10mg, is typically sufficient in prevention of scurvy.
Most adults receive enough vitamin C through their normal diets.