Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. Humans, unlike most animals, are unable to synthesize vitamin C themselves, so it is an essential dietary component.
Vitamin C is an essential vitamin micronutrient that contributes to the normal function of the immune system and the protection of cells from oxidative stress.* It is also known to contribute to normal nervous system psychological function, and helps reduce tiredness and fatigue through involvement in energy yielding metabolism.*Vitamin C contributes to normal collagen formation, and the normal function of bones, teeth, cartilage, gums and skin.* In regards to aiding the use and absorption of other nutrients, Vitamin C helps utilise vitamin E and increases iron absorption.*
Ongoing research is examining whether vitamin C, by limiting the damaging effects of free radicals through its antioxidant activity, might help prevent or delay the development of certain cancers, cardiovascular disease, and other diseases in which oxidative stress plays a causal role*.
Insufficient vitamin C intake causes the skin disease called scurvy. The timeline for the development of scurvy varies, depending on vitamin C body stores, but signs can appear within 1 month of little or no vitamin C intake (below 10 mg/day). Initial symptoms can include fatigue (probably the result of impaired carnitine biosynthesis), malaise, and inflammation of the gums. As vitamin C deficiency progresses, collagen synthesis becomes impaired and connective tissues become weakened.
Oral intake of vitamin C produces tissue and blood plasma concentrations that the body tightly controls. Approximately 70%–90% of vitamin C is absorbed at moderate intakes of 30–180 mg/day. However, at doses over 400mg /d vitamin C starts to be excreted in the urine. Above 1 g/day, absorption falls to less than 50% and absorbed, unmetabolised ascorbic acid is excreted in the urine. For this reason Altruvita sells a sensible and absorbable 250mg dose of vitamin C, perfectly formed into 1 vegan capsule.
* EU REGISTERS ON NUTRITION AND HEALTH CLAIMS