THE SCIENCE OF VITAMIN C: A DETAILED REVIEW

Vitamin C, known as L-ascorbic acid, is an essential water-soluble vitamin in human health, which cannot be synthesized endogenously like most animals. It is crucial in the biosynthesis of collagen, L-carnitine, and neurotransmitters. Protein metabolism also requires vitamin C. Collagen is essential in connective tissue and healing wounds. It has antioxidant properties, capable of regenerating other antioxidants such as vitamin E. In this way, it is possibly helpful in preventing oxidative stress-related diseases, which includes certain cancers and cardiovascular diseases. Vitamin C supports the immune function and helps the absorption of nonheme iron from plant-based foodstuffs. A deficiency causes scurvy, with signs being fatigue, weakness of the connective tissue, and fragile capillaries.Absorption of vitamin C is very tightly regulated; mechanisms include active transport and glucose transporters. The percentage absorbed at moderate intakes, 30–180 mg/day, is between 70–90%. With increasing intakes, absorption drops and excessive amounts are excreted in the urine. From pharmacokinetic studies, plasma levels increase with high intakes, such as 1.25 g/day. Vitamin C is concentrated in tissues like leukocytes, eyes, adrenal glands, and brain, whereas the concentration is less in extracellular fluids as plasma and saliva.